Polymerization reactions and modifications of polymers by ionizing radiation

International audience; Ionizing radiation has become the most effective way to modify natural and synthetic polymers through crosslinking, degradation, and graft polymerization. This review will include an in-depth analysis of radiation chemistry mechanisms and the kinetics of the radiation-induced C-centered free radical, anion, and cation polymerization, and grafting. It also presents sections on radiation modifications of synthetic and natural polymers. For decades, low linear energy transfer (LLET) ionizing radiation, such as gamma rays, X-rays, and up to 10 MeV electron beams, has been the primary tool to produce many products through polymerization reactions. Photons and electrons in…

Kefiran-based Scaffolds For Biomedical Applications

Kefiran is an exopolysaccharide produced by microorganisms present in kefir grains, with several health promoting properties. A optimized protocol was developed for the separation of kefiran from kefir grains, allowing to reach a yield 4÷5 % without using toxic or expensive chemicals. The capability of kefiran to produce scaffold via Thermally Induced Phase Separation (TIPS) technique was investigated and porous scaffolds structure was obtained. Separated kefiran and scaffolds were analyzed via DSC and different thermal properties between purified kefiran and scaffold were revealed. XRD analysis revealed different structure between kefiran and scaffolds. The porous scaffold structure can be…

Synthesis and characterization of biocompatible stimuli-responsive hydrogels

Smart hydrogels with Spheroids of Adipose stem cells for minimally invasive bone and cartilage regeneration

Nanogel-antimiR-31 conjugates affect colon cancer cells behaviour

Soft and flexible nanogels, produced by electron beam (e-beam) irradiation of poly(N-vinyl pyrrolidone) and acrylic acid, were evaluated as delivery devices of the inhibitor of miR-31, a small RNA molecule with an important role in colorectal cancer (CRC) progression. The nanogel carriers developed possess both carboxyl and primary amino groups; the former were activated to react with the primary amino group present in the purposely-functionalised AntimiR-31. Very high conjugation reaction yields were attained, as well as a remarkable colloidal and storage stability of the conjugates. The ability of these nanoconstructs to be internalized by cells and the specific interaction of conjugated …

Radiation curing of 1,2 epoxy – phenoxy propane in the presence of an iodonium salt

Water diffusion and swelling stresses in ionizing radiation cured epoxy matrices

Abstract In this work a DGEBF epoxy monomer was cured by electron beam radiation in the presence of an iodonium salt and the obtained system was hydrothermally aged as such and also after a thermal treatment, in order to obtain two systems having different uniformity in the cross-linking degree. On both systems, the transient stress field arising from swelling was measured and monitored by an optical Photoelastic technique and the results were commented with reference to a thermally cured epoxy system containing the same monomer and already discussed in a previous work. Beam samples with identical dimensions, obtained from the irradiated systems, have been aged at 80 °C in water, and charac…

Properties of Epoxy-Pes systems as polymer matrices for carbon fiber composites produced by e-beam curing

Epoxy based matrices for structural composites prepared by ionizing radiation. Morphological and thermal behaviour

Radiation curing of epoxy resins in the presence of engineering thermoplastic: a way to produce nanostructured matrices for aerospace composites

Multi-Functional Nanogels for Tumor Targeting and Redox-Sensitive Drug and siRNA Delivery

(1) Background: A new family of nanosystems able to discern between normal and tumor cells and to release a therapeutic agent in controlled way were synthetized by e-beam irradiation. This technique permits to obtain biocompatible, sterile, carboxyl-functionalized polyvinylpyrrolidone (PVP-co-acrylic acid) nanogels (NGs); (2) Methods: Here, we performed a targeting strategy based on the recognition of over-expressed proteins on tumor cells, like the folate receptor. The selective targeting was demonstrated by co-culture studies and flow cytometry analysis, using folate conjugated NGs. Moreover, nanoparticles were conjugated to a chemotherapeutic drug or to a pro-apoptotic siRNA through a gl…

Nose-to-brain delivery of insulin enhanced by radiation-engineered nanogels

Recent evidences suggest thet insulin delivery to the brain can be an important pharmacological therapy for some neurodegenerative pathologies, including Alzheimer disease (AD)

Electrically conductive polyaniline-hydrogel nanocompsites

On the mechanism of radiation synthesis of nanogels

Radiation-engineered poly(N-vinyl pyrrolidone) nanogels are very interesting biocompatible nanocarriers for i.v. administration of therapeutics and contrast agents for bioimaging among other applications. Nanogels are usually produced upon irradiation of dilute aqueous polymer solutions. Under these conditions, the polymer radicals formed primarily react via intramolecular radical-radical combination forming intramolecular crosslinks. The manufacturing process is fast and effective and grants excellent control of particle size and simultaneous sterilization of the formed nanogels. Interestingly, primary amino groups and carboxyl groups, useful for (bio)conjugation, are also formed in a dose…

Radiation synthesis of nanogels as therapeutic agent vectors

Nanogels (NGs) are physically or chemically crosslinked polymer networks and are promising candidates in the development of therapeutic agent vectors. In fact, thanks to their tunable size and properties, they offer unique advantages, including a large and flexible surface for multivalent bio-conjugation, an internal 3D aqueous environment for incorporation and protection of (bio)molecular drugs, stimuliresponsiveness to achieve temporal and/or site control of the release function and biocompatibility. In order to develop effective NGs-based biomedical devices an inexpensive, robust and versatile synthetic methodology is required. In this perspective, we have produced NGs with high yields a…

Sub-micron structured Polymethyl Methacrylate/Acrylonitrile-Butadiene rubber blends obtained via gamma radiation induced “in situ” polymerisation

The morphology and properties of PMMA/rubber blends, obtained through gamma radiation induced “in situ” polymerization of methyl methacrylate (MMA) in the presence of small quantities of an acrylonitrile–butadiene based rubber (ABN), are presented. Different systems have been obtained by irradiating at a fixed irradiation dose rate and temperature, varying the integrated dose. All the blends obtained were characterized with respect to their melt state and solid state dynamic-mechanical response and mechanical tensile properties. In particular, the effect on the blend properties of prolonging the irradiation time was investigated. Furthermore, a morphological characterization through atomic …

Electrically conductive polyaniline-hydrogel composites, produced via “in situ” dispersion polymerization

Submicron structured polymethyl methacrylate/acrylonitrile-butadiene rubber blends obtained via gamma radiation induced ?in situ? polymerization

The morphology and properties of PMMA/rubber blends, obtained through gamma radiation induced “in situ” polymerization of methyl methacrylate (MMA) in the presence of small quantities of an acrylonitrile–butadiene based rubber (ABN), are presented. Different systems have been obtained by irradiating at a fixed irradiation dose rate and temperature, varying the integrated dose. All the blends obtained were characterized with respect to their melt state and solid state dynamic-mechanical response and mechanical tensile properties. In particular, the effect on the blend properties of prolonging the irradiation time was investigated. Furthermore, a morphological characterization through atomic …

Numerical simulations of the kinetics of pulsed electron beam induced synthesis of nanogels in dilute aqueous polymer solutions

Nanogel can be produced by irradiation of dilute aqueous polymer solutions. The nanogels are formed primarily through intramolecular radical-radical crosslinking reactions between two polymer radical sites.

Design, synthesis and characterization of a theranostic nanoplatform for tumor site-specific delivery of doxorubicin

HYDROGELS WITH ORDER POROSITY AT THE MESO-SCALE FOR SENSING

Ionizing radiation induced synthesis of polymers and blends with different structures

Laser surface treatments for adhesion improvements of aluminium alloys structural joints

Abstract Laser technology is proposed as a friendly alternative treatment to chemicals involved in conventional prebonding adherend treatments. Aluminium alloy 2024 substrates were laser treated with different beam diameters and energy densities, and bonded using a structural epoxy adhesive. The influence of irradiation conditions on adherends morphology and adhesive joints’ fracture energy was investigated. On the basis of different morphologies observed, an explanation of the effect of the surface treatment upon joint mechanical behaviour is attempted.

Data concerning the protein absorption and retention properties of xyloglucan-based hydrogel film

In wound dressing applications, exudate absorption and retention are important properties. The data presented here assess the ability of the crosslinked xyloglucan-poly(vinyl alcohol) hydrogel films (XG-PVA), described in "Xyloglucan-based hydrogel films for wound dressing: Structure-property relationships" (Ajovalasit et al., 2018) [1] and "Biocompatibility, hemocompatibility and antimicrobial properties of xyloglucan-based hydrogel film for wound healing application" (Picone et al., 2019), to absorb and retain proteins. These properties were investigated by Comassie blue staining and electrophoresis of Fetal Serum Proteins. (C) 2018 The Authors. Published by Elsevier Inc. This is an open …

Biocompatible nanostructured hydrogels incorporating polyaniline nanoparticles

Radiation curing of diacrylate glycerolate of bisphenol-A in the presence of an organically modified montmorillonite for the production of flame-resistant polymer–clay composites

Polymerization of an acrylate derivative of bisphenol-A by ionizing radiation in the presence of an organically modified montmorillonite was carried out in order to produce a flame-retardant composite. The measurement of the thermal effect during irradiation indicates that radiation curing of pure resin and resin-clay mixtures occurred in both cases. Moreover, differential scanning calorimetry and dynamic mechanical thermal analysis showed that a curing completion can be obtained by thermal curing after irradiation with a significant increase of the glass transition temperature. The morphology was investigated by X-ray diffraction and transmission electron microscopy. These have indicated t…

Agarose/κ-carrageenan-based hydrogel film enriched with natural plant extracts for the treatment of cutaneous wounds.

Abstract Hydrogels for complex and chronic wound dressings must be conformable, absorb and retain wound exudates and maintain hydration. They can incorporate and release bioactive molecules that can accelerate the healing process. Wound dressings have to be in contact with the wound and epidermis, even for long periods, without causing adverse effects. Hydrogel dressing formulations based on biopolymers derived from terrestrial or marine flora can be relatively inexpensive and well tolerated. In the present article hydrogel films composed by agarose (1.0 wt%), κ-carrageenan at three different concentrations (0.5, 1.0 and 1.5 wt%) and glycerol (3.0 wt%) were prepared without recourse to cros…

Devices for the capture of rare cells from biological samples for diagnostic purposes

The chance of surviving to a disease often depends on early diagnosis and effective therapy. In the field of early prenatal diagnosis, micromanipulation is a reliable technique for manual selection and isolation of rare fetal cells in maternal biological fluids for molecular or cytogenetic analysis. This technique allows obtaining pure cell populations for analysis, but it is expensive and time consuming, as it requires qualified and experienced staff and specific equipment [1]. This research aims at making the prenatal diagnosis more economical and reproducible in the hospital environment, by creating a device that allows selecting rare cells from biological samples in a semi-automated way…

Radiation processing for synthesis of structural materials

Thermal properties of e-beam cured epoxy/thermoplastic matrices for advanced composite materials

The aim of this work is to investigate the possibility to improve the thermal behaviour of epoxy based systems, cured by ionizing radiation, in order to produce matrices for advanced carbon fibres composites. Blends of two epoxy monomers, difunctional and trifunctional, have been polymerized by e-beam irradiation and the dynamic mechanical thermal properties have been investigated. The increase of the concentration of the trifunctional epoxy monomer in the blend causes a marked increase of the Tg, but strongly decreases the reactivity. Subsequently, blends of the same epoxy monomers with a high Tg thermoplastic toughening agent have been considered and their reactivity and the thermal prope…

On the origin of functionalization in one-pot radiation synthesis of nanogels from aqueous polymer solutions

Radiation-engineered poly(N-vinyl pyrrolidone) nanogels are very interesting biocompatible nanocarriers for i.v. administration of therapeutics and contrast agents for bioimaging. The manufacturing process is fast and effective, it grants excellent control of particle size and simultaneous sterilization of the formed nanogels. Interestingly, primary amino groups and carboxyl groups, useful for (bio)conjugation, are also formed in a dose-dependent fashion. In this paper, by means of both numerical simulations and experiments, the origin of nanogel size control and functionalization is investigated. This understanding offers a new dimension for the design and production of radiation-sculpture…

Recovery from Food Waste-Biscuit Doughs Enriched with Pomegranate Peel Powder as a Model of Fortified Aliment

This research was funded by the "IEV Programme de Cooperation Italie-Tunisie 2014-2020, Re-lancer une nouvelle economie (Re-Ne)". EU project code C-5-3.1-39.

Conductive polymer growth onto radiation grafted polyolefines

Conjugation strategies of insulin to nanogels: new hope for nanogels Alzheimer's disease therapy?

Large-scale manufacturing of radiation sculptured therapeutic nanogels

Nanogels (NGs), or small particles formed by physically or chemically crosslinked polymer networks, represent a niche in the development of “smart” nanoparticles for drug delivery and diagnostics. Yet, they offerunique advantages over other systems, including a large and flexible surface for multivalent bio-conjugation; an internal 3D aqueous environment for incorporation and protection of (bio)molecular drugs; the possibility to entrap light-activemolecules, metal or mineral nanoparticles for imaging or phototherapeutic purposes; stimuli-responsiveness to achieve temporal and/or site control of the release function and biocompatibility. The availability of inexpensive, robust and versatile…

Experimental and numerical procedures for the mechanical characterisation of GFR profiles

Xyloglucan-based hydrogel film for wound dressing: Structure and biological properties relationships

Crosslinked xyloglucan-poly(vinyl alcohol) based hydrogel films have been synthetized and characterized for wound healing applications. Polyvinyl alcohol (PVA) and glycerol (Gro) were added to have an optimal combination of softness, conformability and resilience. Physical hydrogel have been transformed into permanent covalent hydrogels by reaction with glutaraldehyde (GA). Chemical and physical properties of the films have been analyzed by different technique. Moreover, biocompatibility of a selected formulation was assessed in vitro by investigating different aspects, such as cell viability, oxidative stress, mitochondrial dysfunction and specific stress biomarkers. Partial adhesiveness w…

Development and characterization of xyloglucan-poly(vinyl alcohol) hydrogel membrane for Wireless Smart wound dressings

Abstract Hydrogel-based smart wound dressings that combine the traditional favourable properties of hydrogels as skin care materials with sensing functions of relevant biological parameters for the remote monitoring of wound healing are under development. In particular, lightweight, ultra-high frequency radiofrequency identification (UHF RFID) sensor are adjoined to xyloglucan-poly(vinyl alcohol) hydrogel films to battery-less monitor moisture level of the bandage in contact with the skin, as well as wireless transmit the measured data to an off-body reader. This study investigates the swelling behavior of the hydrogels in contact with simulated biological fluids, and the modification of th…

Compositi elettroattivi costituiti da nanoparticelle di polianilina disperse in polivinilpirrolidone

Alternative aluminum pre-bonding surface treatments for the replacement of chromic acid anodizing

“Ionizing radiation induced polymerization of epoxy resin in order to produce carbon fibre composites”

Idrothermal ageing of ionizing radiation cured epoxy matrices for carbon fibre composites

Physico-chemical and mechanical characterization of in-situ forming xyloglucan gels incorporating a growth factor to promote cartilage reconstruction

Abstract The development of growth factors is very promising in the field of tissue regeneration but specifically designed formulations have to be developed in order to enable such new biological entities (NBEs). In particular, the range of therapeutic concentrations is usually very low compared to other active proteins and the confinement in the target site can be of crucial importance. In-situ forming scaffolds are very promising solutions for minimally invasive intervention in cartilage reconstruction and targeting of NBEs. In this work injectable, in-situ forming gels of a temperature responsive partially degalactosylated xyloglucan (Deg-XG) incorporating the growth factor FGF-18 are fo…

Radiation processing per la sintesi di nuovi materiali

RADIATION-ENGINEERED NANOGELS AS GADOLINIUM VECTORS IN BIO-IMAGING

A NEW ROUTE TO OBTAIN PANI-EAA FLEXIBLE FILMS

Smart hydrogels for novel optical functions

Nanocomposites of inherently conductive polyaniline (PANT) within a highly hydrophilic polyvinyl alcohol (PVA) based hydrogel have been produced by coupling a conventional dispersion chemical oxidative polymerization to a subsequent high energy irradiation step, in order to convert the polymer stabilizing the aqueous dispersion, namely the PVA, into a highly water swollen hydrogel incorporating the PANT particles. The incorporation of the electroactive and "pH-sensitive" polymer into a transparent and highly permeable hydrogel matrix has been pursued as a route to the development of a novel class of potentially biocompatible, smart hydrogels that can respond to changes of the surrounding en…

Mechanical testing and numerical modelling of pull-wound carbon-epoxy spinnaker poles

The paper deals with experimental testing and numerical simulation of the mechanical behaviour of multi-layer cylindrical coupons, of two different diameters, made in carbon-epoxy composite. The aim of the study is to provide a simple and effective numerical model that can be used as a design tool for structural elements having analogous geometrical and manufacturing characteristics. The numerical analysis, performed in the elastic regime with a standard finite element (FE) code, was strongly correlated with the laboratory determination of fibre-volume fractions and of some elastic parameters of the material system. Other parameters, like the shear modulus values G, were in fact appropriate…

Poly(vinyl alcohol)/κ-Carrageenan-based hydrogels enriched with the adhesive mussel protein Pvfp5β as 3D cell culture scaffold for tissue engineering applications

Many marine organisms such as sandcastle worms, barnacles and mussels, produce natural adhesives to attach to wet surfaces in aqueous tidal environments. In mussels, the adhesion is possible through the secretion of a protein-based water-resistant glue, composed of a mixture of proteins called mussel adhesive proteins (MAPs) or mussel foot proteins (mfps), that allow anchoring to almost any kind of surface in wet conditions [1]. The proteins confined to adhesive plaques are mfp-2, -3, -4, -5, and -6. All these proteins contain an atypically high concentration of the catecholic amino acid 3,4- dihydroxy-l-phenylalanine (DOPA), obtained by the post-translational enzymatic hydroxylation of tyr…

Xyloglucan-based hydrogel films for the design of "smart" bandages

A chronic wound is a wound that does not heal in an orderly set of stages and in a predictable amount of time the way most wounds do. Chronic wounds mostly affect people over the age of 60, but a significant proportion is becoming radiation induced chronic wounds caused by cancer radiotherapy. Hydrogels are often used as dressings in the management of a variety of wounds. These materials can help to maintain a moist wound environment, promote natural debridement, hydrate necrotic tissue, absorb slough and exudates.We are developing hydrogel dressings that can enable constant monitoring of selected key parameters through embedded radio-sensors, providing information on the progress of the re…

Realizzazione di Giunti Strutturali Mediante Polimerizzazione di Sistemi Adesivi Indotta da Fasci di Elettroni

Radiation engineered functionalized nanogels as platform for biomedical nanocarriers

Optical properties of biocompatible polyaniline nano-composites

Abstract Polyaniline (PANI) is an electro-active polymer of great interest thanks to its outstanding physical and chemical properties which make it suitable for various applications in optics, bioelectronics, biosensors, diagnostics and therapeutic devices. Unfortunately, PANI is infusible and insoluble in most common solvents and, thus, very difficult to process. In the attempt of improving processability, yet preserving its interesting properties, PANI has been synthesized in the form of particles and dispersed into a hydrogel matrix. The synthesis of PANI–hydrogel composites proceeds via γ-irradiation of PANI dispersions as obtained by ‘in situ’ polymerization of aniline in the presence …

Insulin Nanogels: a New Strategy for the Treatment of Alzheimer’s Disease

A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signaling are involved in brain cognitive functions and their dysfunction is implicated in Alzheimer’s disease (AD) degeneration. Thus, administration of insulin could be a strategy for AD treatment. For this aim we have designed, synthesized and characterized a nanogel system (NG) to deliver insulin to the brain, as a tool for the development of a new therapy for AD. A carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system produced by ionizing radiation was chosen as substrate for the covalent attachment of insulin or fluorescent molecules relevant for its characterization. Biocompatibility of the naked c…

Toughened epoxy matrices produced by e-beam irradiation

Radiation-tailored xyloglucan-doxorubicin nanoparticles for cancer therapy

Polysaccharides are long chains of monosaccharides linked by glycosidic bonds. They are widely utilized in biomedical applications, for tissue engineering and wound management, and as excipients of pharmaceutical formulations. In cancer therapy, the development of nanoscale drug delivery systems aims at addressing issues related to the low efficacy of chemotherapeutics and protein drugs due to poor solubility and stability, and to off-target effects that severely affect patients’ body conditions. Biocompatibility, availability of functional groups, amenability of chemical derivatisation and multifunctional conjugation with drugs and targeting ligands make polysaccharide nanoparticles intere…

Inherently fluorescent polyaniline nanoparticles in a dynamic landscape

Abstract In this paper we report for the first time on the emissive behavior of two polyaniline (PANI) nanoparticle systems produced via oxidative chemical polymerization in the presence of either poly(vinyl alcohol) (PVA) or chitosan as polymeric stabilizers in water. The emission from PANI nanoparticles is irreversibly quenched by an increase of pH of the suspending medium from acid to neutral (chitosan–PANI) or alkaline (PVA–PANI). Conversely, PANI nanorods synthesized in the same conditions of the above, but in presence of poly(N-vinyl pyrrolidone), is not emissive at any pH. The role of the polymeric surfactant as a soft template is key in controlling the morphology and the properties …

Numerical Simulation of the Kinetics of Radical Decay in Single-Pulse High-Energy Electron-Irradiated Polymer Aqueous Solutions

A new method for the numerical simulation of the radiation chemistry of aqueous polymer solutions is introduced. The method makes use of a deterministic approach combining the conventional homogeneous radiation chemistry of water with the chemistry of polymer radicals and other macromolecular species. The method is applied on single-pulse irradiations of aqueous polymer solutions. The speciation of macromolecular species accounts for the variations in the number of alkyl radicals per chain, molecular weight, and number of internal loops (as a consequence of an intramolecular radical-radical combination). In the simulations, the initial polymer molecular weight, polymer concentration, and do…

Radiation processing: an alternative and environmentally friendly way to produce advanced Materials. Synthesis of PANI/hydrogels composites

Processi di cura di resine epossidiche mediante radiazioni ionizzanti per la realizzazione si materiali compositi per il settore aerospaziale. Influenza delle condizioni operative sulle proprietà finali

Influence of Nylon 6,6 nanofiber mats on cure behavior and properties of CFR epoxy resin

In this work Nylon 6,6 nanofibrous mats produced by electrospinning were used as interlayers in carbon fiber reinforced laminates. A high crossilinked epoxy resin was chosen as matrix. The effects of polymeric mats on cure behavior, thermal and delamination properties of the composite laminates were investigated.

Radiation engineered nanogels as platform for next-generation of medical diagnostics and therapeutics

Gamma radiation of EVA-AA/MMA swollen systems to obtain mechanically improved blends

In this work a "new" way to obtain "compatibilised" blends of rubber-glassy thermoplastic components is presented. Polyethylen-vinyl acetate acrylic acid terpolymer is swollen by methylmetacrylate and the system is irradiated through gamma rays in order to induce polymerisation of the monomer. Solubility and dynamic mechanical tests indicate the formation of a two phase system, even though in presence of strong interactions between the two components. Mechanical tensile behaviour is that of a ductile material with appreciable modulus values.

Electric properties of gamma-crosslinked hydrogels incorporating organic conducting polymers

Minimalism in radiation synthesis of biomedical functional nanogels.

A scalable, single-step, synthetic approach for the manufacture of biocompatible, functionalized micro- and nanogels is presented. In particular, poly(N-vinyl pyrrolidone)-grafted-(aminopropyl)methacrylamide microgels and nanogels were generated through e-beam irradiation of PVP aqueous solutions in the presence of a primary amino-group-carrying monomer. Particles with different hydrodynamic diameters and surface charge densities were obtained at the variance of the irradiation conditions. Chemical structure was investigated by different spectroscopic techniques. Fluorescent variants were generated through fluorescein isothiocyanate attachment to the primary amino groups grafted to PVP, to …

Electrically conductive hydrogel composites made of polyaniline nanoparticles and poly(N-vinyl-2 pyrrolidone)

Electrically conductive polyaniline-hydrogel nanocomposites

ENGINEERED NANOGELS FOR BIOLOGICAL DRUGS TRANSPORT

Nowadays the nanocarrier strategy, aimed to rebuild the tumor therapy approach in a winning way, is growing very fast. This is in the direction to engender nanocarriers having synergistic action by the “biological drugs” transported, the capability to recognize specific targets and the molecular architecture that allows them to perform at the best their therapeutic functions. We are building engineered nanocarriers having different functions (control cell cycle, induce apoptosis, etc.) as well as the capability to recognize specific targets (tumor cells, angiogenic and/or sprouting endothelial cells); moreover, they must have also the ability to escape the host immunosystem, such that not t…

Ethanol vapor optical sensors based on polystyrene opals infiltrated with hydrogel

Recombinant mussel protein Pvfp5β enhances cell adhesion of poly(vinyl alcohol)/k-carrageenan hydrogel scaffolds

Polymeric hydrogels are increasingly being considered as a scaffold for tissue engineering because they show similarity to the extracellular matrix (ECM) of many tissues. To control various cellular processes, hydrogels are often functionalized or loaded with various bioactive molecules such as: specific ligands for adhesion receptors, growth factors, hormones, enzymes, and other natural or synthetic regulators of cellular behavior [1]. Cell adhesion is essential for cell communication and regulation of the cell cycle and is therefore of vital importance in tissue engineering. Biomimetic approaches have been investigated to facilitate cell-scaffold adhesion interactions. In particular, the …

Rare cell capture platforms based on antibody-conjugated electrospun nanofiber mats for noninvasive prenatal diagnostics

The chance of surviving to a disease often depends on early diagnosis and effective therapy. In the field of early prenatal diagnosis, micromanipulation is a reliable technique for manual selection and isolation of rare fetal cells in maternal biological fluids for molecular or cytogenetic analysis. This technique allows obtaining pure cell populations for analysis, but it is expensive and time consuming, as it requires qualified and experienced staff and specific equipment [1]. The aim of this study is to make the prenatal diagnosis more economical and reproducible in the hospital environment, by creating a device that allows selecting rare cells from biological samples in a semi-automated…

Physical and structural characterization of blends made with polyamide 6 and gamma-irradiated polyethylenes

Abstract Morphological, calorimetric and rheological results of blends made with polyamide 6 and polyethylene gamma irradiated in air are presented. The polar oxidized groups grafted in the poliolefin chains through gamma-radiation induce “compatibilization” effects in the blends with a more uniform and finer distribution of the polyethylene “phase” in the polyamide matrix, with respect to blends made with the unirradiated polymer. This effect, observed with polyethylenes of different molecular structure, i.e. low density, linear low density and high density, was attributed to the presence of interactions among the functional oxidized groups of the polyethylene chains and the polyamide. Tes…

Radiation-Engineered Multi-Functional Nanogels As Nanoscale Building Blocks Of Useful Biomedical Devices

Nose-to-brain delivery of insulin enhanced by a nanogel carrier.

Recent evidences suggest that insulin delivery to the brain can be an important pharmacological therapy for some neurodegenerative pathologies, including Alzheimer disease (AD). Due to the presence of the Blood Brain Barrier, a suitable carrier and an appropriate route of administration are required to increase the efficacy and safety of the treatment. Here, poly(N-vinyl pyrrolidone)-based nanogels (NG), synthetized by e-beam irradiation, alone and with covalently attached insulin (NG-In) were characterized for biocompatibility and brain delivery features in a mouse model. Preliminarily, the biodistribution of the "empty" nanocarrier after intraperitoneal (i.p.) injection was investigated b…

SELF-ASSEMBLY OF DEGALACTOSYLATED XYLOGLUCAN FROM TAMARIND SEEDS

Nanostructured surfaces of aluminium alloys for fabricating adhesive bonded joints

The influence of the processing temperature on gamma curing of epoxy resins for advanced composites

The role of molecular oxygen in the formation of radiation-engineered multifunctional nanogels

Abstract Nanogels are very promising biomedical nanodevices. The classic “radiation chemistry-based” approach to synthetize nanogels consists in the irradiation with pulsed electron beams of dilute, N2O-saturated, aqueous solutions of water-soluble polymers of the “crosslinking type”. Nanogels with controlled size and properties are produced in a single irradiation step with no recourse to initiators, organic solvents and surfactants. This paper combines experimental syntheses, performed with two e-beam irradiation setups and dose-ranges, starting from poly(N-vinyl pyrrolidone) solutions of various concentrations, both in N2O-saturated and air-saturated initial conditions, with the numerica…

Pharmaceutical compositions in the form of gel containing xyloglucan and alcohols for the controlled release of active ingredients

The invention relates to gel compositions comprising pharmaceutical active ingredients. The composition comprises xyloglucan at concentration between 0.1% and 10.0% by total weight of the composition, together with a primary alcohol at a concentration between 20.0 and 50.0% by total weight of the composition. The invention also describes a process for the preparation of the composition and its use in the treatment of pathologies wherein a controlled release of the active principle is useful.

Synthesis and characterization of biocompatible responsive hydrogels

Radiation curing of an epoxy resin based system under controlled temperature conditions

Hydrogel Nanocomposites Containing Polyaniline With Different Morphologies for Possible Bioengineering Applications

RADIATION CROSSLINKED ADVANCED WOUND DRESSING CONTAINING EGG WHITE PROTEINS

During the past decades, the use of antibiotics has grown worldwide in different fields, from medicine to agriculture, leading to antibiotic resistance of microbes, which is the cause of thousands of deaths every year worldwide. [1, 2] Finding new antibiotics is becoming more and more difficult because their development is no longer convenient in term of the cost–benefit ratio for the pharmaceutical industry. The interest in egg white proteins, such as ovoalbumin, ovotransferrin and lysozyme, has risen especially because of their demonstrated antimicrobial activities. [3] These antimicrobial proteins can then be used to enrich wound dressing films that requires a high level of control of mi…

Multifunctional nanogels from e-beam irradiation of PVP aqueous solutions, only

Nanogels (NGs) are 3D networks of crosslinked hydrophilic polymers with nanoscalar dimensions. Due to their structure and physico-chemical properties, they are a promising nanomaterial platform for site-specific drug delivery and diagnostic nanodevices.

Development and Characterization of an Amorphous Solid Dispersion of Furosemide in the Form of a Sublingual Bioadhesive Film to Enhance Bioavailability.

Administered by an oral route, Furosemide (FUR), a diuretic used in several edematous states and hypertension, presents bioavailability problems, reported as a consequence of an erratic gastrointestinal absorption due to various existing polymorphic forms and low and pH-dependent solubility. A mucoadhesive sublingual fast-dissolving FUR based film has been developed and evaluated in order to optimize the bioavailability of FUR by increasing solubility and guaranteeing a good dissolution reproducibility. The Differential Scanning Calorimetry (DSC) analyses confirmed that the film prepared using the solvent casting method entrapped FUR in the amorphous state. As a solid dispersion, FUR increa…

Radiation curing of carbon fibre composites

Epoxy/carbon fibre reinforced composites were produced by means of e-beam irradiation through a pulsed 10 MeV electron beam accelerator. The matrix consisted of a difunctional epoxy monomer (DGEBA) and an initiator of cationic polymerisation, while the reinforcement was a unidirectional high modulus carbon fibre fabric. Dynamic mechanical thermal analysis was carried out in order to determine the cross-linking degree. The analysis pointed out a nonuniformity in the cross-linking degree of the e-beam cured panels, with the formation of clusters at low Tg (glass transition temperature) and clusters at high Tg. An out-of-mould post irradiation thermal treatment on e-beam cured samples provides…

IAEA Contribution to Nanosized Targeted Radiopharmaceuticals for Drug Delivery.

The rapidly growing interest in the application of nanoscience in the future design of radiopharmaceuticals and the development of nanosized radiopharmaceuticals in the late 2000′s, resulted in the creation of a Coordinated Research Project (CRP) by the International Atomic Energy Agency (IAEA) in 2014. This CRP entitled ‘Nanosized delivery systems for radiopharmaceuticals’ involved a team of expert scientist from various member states. This team of scientists worked on a number of cutting-edge areas of nanoscience with a focus on developing well-defined, highly effective and site-specific delivery systems of radiopharmaceuticals. Specifically, focus areas of various teams of scientists com…

E-beam crosslinked, biocompatible functional hydrogels incorporating polyaniline nanoparticles

Abstract PANI aqueous nanocolloids in their acid-doped, inherently conductive form were synthesised by means of suitable water soluble polymers used as stabilisers. In particular, poly(vinyl alcohol) (PVA) or chitosan (CT) was used to stabilise PANI nanoparticles, thus preventing PANI precipitation during synthesis and upon storage. Subsequently, e-beam irradiation of the PANI dispersions has been performed with a 12 MeV Linac accelerator. PVA-PANI nanocolloid has been transformed into a PVA-PANI hydrogel nanocomposite by radiation induced crosslinking of PVA. CT-PANI nanoparticles dispersion, in turn, was added to PVA to obtain wall-to-wall gels, as chitosan mainly undergoes chain scission…

Radiation Curing of Thermosetting- Thermoplastic Blends as Matrices for Structural Carbon Fibre Composites

Gadolinium-chelating nanogels as MR contrast agesnts specifically targeting tumor cells

Development of multifunctional nanogels coordinating paramagnetic ions and displacing targeting ligands for preferential accumulation into tumors. Low molecular-weight Gd-chelates are widely used in clinical MRI for various purposes. However, these contrast agents (CAs) have several shortcomings: they rapidly extravasate from blood vessels to the interstitial space, have a short circulation times and show poor contrast at high magnetic fields. Incorporating gadolinium into flexible nanogels has the potential of increasing intravascular half-life, accumulation and retention in specific body compartments of the CA as well as increasing the MR signal, since many metal ions can be coordinated t…

Synthesis od epoxy/carbon fiber composites induced by e-beam. Study of the effect of hydrothermal ageing on thermal and mechanical properties

NANOGELS AS USEFUL TOOL FOR ALZHEIMER’S DISEASE THERAPY

Maltose-conjugated chitosans induce macroscopic gelation of pectin solutions at neutral pH

Injectable polymer scaffolds are particularly attractive for guided tissue growth and drug/cell delivery with minimally invasive intervention. In the present work, "all-polymeric" gelling systems based on pectins and water-soluble maltose-conjugated chitosans (CM) have been developed. Maltose-conjugated chitosan has been synthesized at three different molar ratios, as evaluated by FITR analysis and fluorimetric titration. A thorough rheological characterization of the blends and their parent solutions has been performed. Macroscopic gelation has been achieved by mixing the high esterification degree pectins with CM at higher maltose grafted to chitosan contents. Gels form in a few minutes a…

Structure and biological evaluation of amino-functionalized PVP nanogels for fast cellular internalization

Abstract Aminopropyl methacrylamide chloride-graft-poly(N-vinyl pyrrolidone) nanogels (NGs) were designed to exploit the favorable properties of poly(N-vinyl pyrrolidone) (PVP), such as its high affinity to water and complexation ability of ions, molecules and macromolecules, with the availability of primary amino groups for bioconjugation reactions. A thorough structural characterization of the nanoscalar networks was performed via 1 H NMR and solid state 13 C NMR spectroscopies, while solid state NMR relaxation time measurements completed the NGs description in terms of polymer network density. Information on the hydrodynamic size and surface charge densities were sought via dynamic light…

Radiation sculpured nanogels as platform for novel therapeutic systems

Multifunctional and Bio-hybrid Hydrogel As bioartificial Matrices and Drug Delivery Devices

CONJUGATION STRATEGIES OF INSULIN TO NANOGELS AND BIOLOGICAL ACTIVITY TESTS

Influence of gamma-irradiation on thermally-induced mesoscopic gelation of degalactosylated xyloglucans

Thermoresponsive degalactosylated xyloglucans have been already proposed as in situ gelling scaffolds for tissue engineering, due to their reversible macroscopic thermal gelation at body temperature and biodegradability. The highly branched, hydroxyl group-rich molecular structure renders xyloglucans interesting raw materials also in the form of micro/nanoparticles for application as nanoscalar drug delivery devices in cosmetic and pharmaceutical formulations. Owing to their natural source, xyloglucans show high average molecular weight, broad molecular weight distribution and poor water solubility, as large and compact aggregates usually form via inter-molecular hydrogen bonding. Co-60 gam…

Accelerated ageing due to moisture absorption of thermally cured epoxy resin/polyethersulphone blends. Thermal, mechanical and morphological behaviour

Abstract A model epoxy resin/anhydride system, modified with a polyethersulfone (PES) engineering thermoplastic toughening agent, has been studied under hydrothermal ageing in order to investigate the modification of the thermal, morphological and mechanical behaviour through dynamical mechanical thermal analysis, SEM microscopy and fracture toughness test respectively. Two different concentrations of the toughening agent were used in the blends and two ageing conditions have been considered, consisting of the immersion of the samples in distilled water at constant temperature of 70 °C for 1 week and for 1 month. Dynamical mechanical thermal analysis results on hydrothermally aged materials…

Advances in Conductive Polymers/Hydrogel Nanocomposites

Water-borne polymeric nanoparticles for glutathione-mediated intracellular delivery of anticancer drugs

A new family of water-borne, biocompatible and carboxyl- functionalized nanogels was developed for glutathione- mediated delivery of anticancer drugs. Poly(N-vinyl- pyrrolidone)-co-acrylic acid nanogels were generated by e- beam irradiation of aqueous solutions of a crosslinkable polymer, using industrial-type linear accelerators and set- ups. Nanogels physico-chemical properties and colloidal stability, in a wide pH range, were investigated. In vitro cell studies proved that the nanogels are fully biocompatible and able to quantitatively bypass cellular membrane. An anticancer drug, doxorubicin (DOX), was linked to the carboxyl groups of NGs through a spacer containing a disulphide cleavab…

Water-borne e-beam crosslinked nanogels as nanomaterials platform for drug delivery

RADIATION CURING OF CARBON FIBRE COMPOSITES

Degalatosylated xyloglucan hydrogels: influence of irradiation conditions on physico-chemical properties and structure

Laser surface treatments for adhesion improvements of alluminium alloys structural joints

Ionizing radiation-engineered nanogels as insulin nanocarriers for the development of a new strategy for the treatment of Alzheimer's disease

A growing body of evidence shows the protective role of insulin in Alzheimer's disease (AD). A nanogel system (NG) to deliver insulin to the brain, as a tool for the development of a new therapy for Alzheimer's Disease (AD), is designed and synthetized. A carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system produced by ionizing radiation is chosen as substrate for the covalent attachment of insulin or fluorescent molecules relevant for its characterization. Biocompatibility and hemocompatibility of the naked carrier is demonstrated. The insulin conjugated to the NG (NG-In) is protected by protease degradation and able to bind to insulin receptor (IR), as demonstrated by immunofl…

Nano structured systems synthesised by ionizing radiation

Nanostructured soft composites for an interactive interface between Human and the environment

Dielectric characterization of biocompatible hydrogels for application to Epidermal RFID devices

Functionalized skin-like membranes are currently under investigation for the design of a new class of Epidermal Electronics devices for sensing and healing applications. The dynamic response of epidermal antennas in presence of absorption and release of fluids is a key-point to design RFID radio-sensors and actuators. This paper addresses the characterization of the dielectric property of PVA-based biocompatible hydrogel membranes in the UHF RFID band by means of a modified ring resonator. Samples having different compositions are measured in the dry state as well as when exposed to a progressive release of body fluids emulating perspirations or wound exudates. It was found that the permitt…

Opals infiltrated with a stimuli-responsive hydrogel for ethanol vapor sensing

We report on a novel class of optical materials for ethanol vapor sensing, based on polystyrene opals infiltrated with an innovative stimuli responsive hydrogel. We describe the fabrication process of the bare polystyrene opals and their subsequent infiltration. The optical characterization of the photonic crystal templates was performed to prove the good quality of the samples. Measurements on the infiltrated opals showed that the transmission spectra in the visible range strongly change at varying concentrations of ethanol vapor. The fabricated structures show a linear optical response in the visible range, for high values of ethanol concentration.

Properties-morpholohy-processing relationships in the e-beam curing of epoxy resin-thermoplastic blends for advanced composite matrices

FOLATE-DECORATED E-BEAM CROSSLINKED NANOGELS TO ENHANCE UPTAKE BY TUMOR CELLS

Synthesis and characterization of water-swellable?,?-polyasparthydrazide derivatives

α, β-polyasparthydrazide (PAHy) was crosslinked by glutaraldehyde to form water-swellable materials possessing a three-dimensional molecular network. Different crosslinking degrees were prepared varying glutaraldehyde/PAHy ratio and samples containing 5-fluorouracil were obtained by incorporating the drug into the polymer networks during the crosslinking reaction. All samples were characterized by swelling tests, thermal, x-ray and SEM analysis. Their microstructure was observed through scanning electron microscopy. Furthermore, for samples containing the anticancer drug,in vitro release studies were performed in pH 7.4 buffer solution.

Probing the internal environment of PVP networks generated by irradiation with different sources

Poly(N-vinyl-2-pyrrolidone) (PVP) hydrogels have been synthesised from the aqueous solutions of the same linear polymer by two different radiation sources: electron beams and UV rays. The present investigation couples conventional hydrogel characterisation techniques with the study of the partition equilibria, fluorescence behaviour and release of two different molecular probes, 1-anilino-8-naphthalene sulphonate (ANS) and Thioflavin T (ThT). The two probes have comparable molecular weight and different structural and optical properties. The ‘chemical’ networks produced upon irradiation in different experimental conditions presented quite distinctive mechanical spectra, yielded to different…

E-Beam Crosslinked Polymeric and Bio-Hybrid Nanocarriers for Drug Delivery and Bioimaging

Irradiation of low density and high density polyethylenes in presence of carbon dioxide in subcritical and supercritical conditions

Abstract The grafting of carboxylated and oxygenated functions on low density and high density polyethylenes is carried out by gamma irradiation in the presence of carbon dioxide. Both crosslinking and grafting of oxidised groups occur. The extent of these molecular modifications depends on the physical conditions of the gas phase and on the nature of the polymer matrix.

Thermal and mechanical properties of polymer matrices for carbon fibre composites produced by radiation curing of Epoxy-Pes blends

Control of end-of-life oxygen-containing groups accumulation in biopolyesters through introduction of crosslinked polysaccharide particles

The formulation of bio-based materials with good performance in service and controlled end-of-life is imperative for an effective circular economy. In this work, an innovative approach to induce and control the end-of-life of biodegradable polyesters through introduction of crosslinked polysaccharide particles is proposed. Chitosan (Ch) has been subjected to ionotropically crosslinking and then added to polylactic acid (PLA) at different amounts (1.0–4.0%w) by melt mixing. All obtained results suggest that the addition of crosslinked Ch (cCh) particles does not modify significantly the investigated biopolyester properties. Specifically, the thermal analysis of the composites reveals that th…

Synthesis, characterisation and properties of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide-graft-maleic anhydride precursors and their stimuli-responsive hydrogels

Abstract A family of poly(amino acid)-maleic anhydride hydrogels were designed and synthesized. Water soluble polymeric precursors were prepared by partially substituting the hydroxyl groups of the α,β-poly( N -2-hydroxyethyl)- dl -aspartamide backbone with maleic anhydride, so as to provide double bonds for crosslinking and carboxylic acid groups for pH and electric field responsiveness. Reaction conditions (reactive mixture composition and catalysis) were systematically varied in order to obtain PHEA–MA precursors with different and reliable graft-maleic anhydride levels. PHEA–MA precursors were characterised by titration, Nuclear Magnetic Resonance ( 1 H NMR), Fourier-Transformed Infrare…

Polymer matrices for composites obtained through radiation curing of epoxy resins

Macromolecular engineering of hydrogels: from macro to nano scalar materials for different levels of biointeraction

Hydrogel films engineered in a mesoscopically ordered structure and responsive to ethanol vapors

Abstract Responsive hydrogels filling the interstitial spaces of photonic crystals can form mesoscopically structured materials, which exhibit reversible shifts in the Bragg diffracted light as a response of environmental changes. These materials can be used to generate chemical or biochemical sensors. The present work reports on the synthesis and characterization of ethanol responsive hydrogels that can be used in the design of novel breathalyzers. The dynamic mechanical behavior of the macroscopic hydrogels and their swelling features in the presence of different liquids or vapors have been investigated to orientate the choice of the best responsive material and curing process. The swelli…

Matrici polimeriche nanostrutturate per materiali compositi ottenute mediante radiazioni ionizzanti

Recombinant mussel protein Pvfp5β enhances cell adhesion of poly(vinyl alcohol)/k-carrageenan hydrogel scaffolds

Polymeric hydrogels are increasingly considered as scaffolds for tissue engineering due to their extraordinary resemblance with the extracellular matrix (ECM) of many tissues. As cell adhesion is a key factor in regulating important cell functions, hydrogel scaffolds are often functionalized or loaded with a variety of bioactive molecules that can promote adhesion. Interesting biomimetic approaches exploit the properties of mussel-inspired recombinant adhesive proteins. In this work, we prepared hydrogel scaffolds with a 50%w mixture of k-carrageenan (kC) and polyvinyl alcohol (PVA), by a two-step physical gelation process, and we coated them with Perna viridis foot protein-5 beta (Pvfp5 be…

Advances in Conducting Polymers/hydrogel Nanocomposites

Effects of Nylon 6,6 Nanofibrous Mats on Thermal Properties and Delamination Behavior of High Performance CFRP Laminates

none 8 no Nylon 6,6 electrospun nanofibrous membranes interleaved in Carbon Fibre Reinforced Plastic (CFRP) laminates have been proposed as a means to provide a higher threshold value to delamination on structural sites where composites are more prone to develop such failure. A model, highly crosslinked thus inherently brittle, epoxy matrix was selected for its high Young’s modulus and glass transition temperature exceeding 250 °C. The influence of the Nylon 6,6 nanofibres on the curing behaviour of the matrix and on the thermal and dynamic mechanical properties of the cured resin was investigated. These properties were related to the features of the epoxy resin and of the resin impregnated…

Radiation-engineered polymer nano-platforms for targeted drug delivery

In the last twenty years, several nanobiomaterial-based nanocarriers, so-called nanoplatforms, have been proposed for the treatment of life- threating or quality-of-life-impairing diseases. The role of the nanocarrier is to increase drug localisation via passive and active targeting, to protect the drug from degradation and premature clearance, to facilitate its bypass through biological barriers and increase uptake by cells. For a successful translational research, the system composition should be as simple as possible, and the manufacturing processes should be fast, flexible and should enable a rapid product development from lab-scale to low cost, large-scale production. With this focus, …

The influence of the nature of the surface oxide on the adhesive fracture energy of aluminium-bonded joints as measured by T-peel tests

Abstract Modification of aluminium alloy substrates microstructure and morphology by depositing new oxide layers on top of the metal surface has been investigated, with the aim of improving adhesion. The effect of treating the metal with boiling water or immersing it in a cerate bath has been studied by means of electron microscopy, contact angle measurements and peeling tests. The formation of pseudoboehmite layers or cerium conversion coatings both led to an increase in joint's adhesive fracture energy and more durable adhesive bonds with respect to joints obtained with “mechanically grinded only” substrates. Differences in the performance of the bonded joints has been discussed in terms …

Electrospun rubber/thermoplastic hybrid nanofibers for localized toughening effects in epoxy resins

Synthetic rubber/thermoplastic blends were electrospun from their solutions. The rubber was a solid acrylonitrile/butadiene/acrylic acid copolymer and the thermoplastic was polyacrylonitrile. The aims of this study were to identify suitable systems and processing conditions for obtaining rubber-based electrospun nanofibers, to investigate the ability of an epoxy resin system to impregnate and swell selected hybrid rubber/thermoplastic mats, and to assess the impact of the nanofibers on the resin morphology and curing behavior. In particular, electrospinning trials were carried out varying the composition of the feed solution and process parameters, such as the applied voltage, the flow rate…

Radiation engineered polymer nanocarriers for a new generation of nanoparticles based tumor specific radiopharmaceuticals

High energy radiation processing for the synthesis of insulin nanocarriers for the development of a new strategy for the treatment of Alzheimer's Disease

Nanogels are nanoscalar polymeric networks, characterized by a dynamic internal structure and a flexible adaptive shape. When they are used as drug carriers, their flexibility and shape changing ability can facilitate the bypass of biological barriers, ensure protection of the payload and enable interaction of any attached ligand with its receptors. Poly(N-vinyl pyrrolidone)-co-acrylic acid nanogels (NGs) have been produced by ebeam irradiation of diluted aqueous solutions of a water-soluble polymer in the presence of a small amount of acrylic acid. In particular, industrial accelerators and the typical set-ups and doses applied for sterilization have been used. [1, 2] Particle size, molecu…

Ionizing radiation induced curing of epoxy resin based systems for advanced composites matrices

Temperature-responsive cellulose-based hydrogels as draw agents in Forward Osmosis

Forward Osmosis is a powerful tool to produce clean water at a low cost if appropriate draw agents and regeneration methods are employed (1). In this frame, stimuli-responsive hydrogels are interesting candidates due to their ability to uptake water and release it under physical stimuli, such as hydrostatic pressure and temperature variations. In particular, temperature-responsive hydrogels that are able to absorb large amount of water at room temperature and release it upon a slight temperature increase are very appealing candidates because they can be regenerated easily and with very low energy consumption (2). Chemical stability and biocompatibility are two further requirements that hydr…

High-energy radiation processing, a smart approach to obtain PVP-graft-AA nanogels

Abstract Poly(N-vinylpyrrolidone)-grafted-acrylic acid biocompatible nanogels (NGs) were prepared using an exiting industrial-type electron accelerator and setups, starting from semi-dilute aqueous solutions of a commercial PVP and the acrylic acid monomer. As a result, NGs with tunable size and structure can be obtained quantitatively. Sterility was also imparted at the integrated dose absorbed. The chemical structure of the NGs produced was confirmed through Fourier Transformer Infrared Spectroscopy (FT-IR). The molecular and physico-chemical properties of NGs, such as the hydrodynamic dimensions and surface charge densities, for various polymer and monomer concentrations in the irradiate…

The influence of the processing temperature on gamma curing of epoxy resins for the production of advanced composites

Abstract Gamma radiation curing of an epoxy monomer, in the presence of an iodonium salt, as initiator, is studied. Systems have been polymerized at the same irradiation dose and dose rate and at different processing temperatures. The experimental results show that all the irradiated materials exhibit a latent reactivity, undergoing toward an increase of crosslinking density if they are thermally cured after irradiation. The results indicate that the processing temperature affects both the crosslinking density after irradiation and the sensibility to the post-irradiation thermal treatment.

Gelation of degalactosylated xyloglucan from nano to macroscopic scale

Partially degalactosylated xyloglucans are able to form thermo-reversible gels in aqueous solution at physiological temperature. This property makes them very promising materials for tissue engineering. Moreover, due to a highly branched, hydroxyl group-rich molecular structure, xyloglucans are particularly interesting for manufacturing of micro/nanoparticles to be used as nano-scalar delivery devices of active ingredients in cosmetic and pharmaceutical formulations. Here we present results on the temperature-induced self-assembly of degalactosylated xyloglucan at varying polymer concentration from dilute to semi-dilute regime. Our aim is to investigate the gelation mechanism for gaining in…

Large-scale radiation manufacturing of hierarchically assembled nanogels

Nanogels (NGs), or small particles formed by physically or chemically crosslinked polymer networks, represent a niche in the development of "smart" nanoparticles for drug delivery and diagnostics. They offer unique advantages over other systems, including a large and flexible surface for multivalent bio-conjugation; an internal 3D aqueous environment for incorporation and protection of (bio)molecular drugs; the possibility to entrap active metal or mineral cores for imaging or phototherapeutic purposes; stimuli-responsiveness to achieve temporal and/or site control of the release function and biocompatibility. The availability of inexpensive and robust preparation methodologies is at the ba…

Influence of Polymer Electrospun Nanofibers on Thermal Properties of Epoxy Resins

Electrospinning of polymers has gained surging interest in the last decades due to its wide range of applications in different fields, such as sensors, electronic devices, separation systems, biomedical materials. Still there are only few reports on the use of these nanofibers as reinforcement in polymer composites. In this paper, solution electrospinning was employed to produce nanofibrous mats impregnating two epoxy resins to form “monolayer“ systems, with the aim to study the influence of the nanofibers on both the curing behaviour and the morphology of the resin systems. Three polymers were chosen for producing electrospun mats, a polysulfone (PSF), a polyamide Nylon 6,6 (Ny66) and a po…

Optical sensors for ethanol vapor based on polystyrene opals infiltrated with hydrogel

This paper deals with a novel class of optical sensors for ethanol vapor, based on polystyrene opals infiltrated with a hydrogel sensitive to ethanol. Optical characterization of such opals has been performed, proving their effectiveness as sensors

POLYSACCHARIDE-BASED HYDROGELS FOR MYOCARDIUM REMODELING

Idrogeli a base di xyloglucano per la produzione di medicazioni avanzate nel trattamento delle ferite

In questo lavoro sono stati preparati film sottili di idrogelo (reticolati fisicamente o chimicamente) a base di xyloglucano (XG) e XG/polivinilalcol (PVA), a cui si è aggiunto glicerolo come plasticizzante. Lo xyloglucano è un polisaccaride di origine vegetale, caratterizzato da una catena principale di (1,4)--Dglucosio con ramificazioni laterali di (1-6)-α-xilosio, parzialmente sostituite con (1-2)–β galattosio. E’ stata indagata la possibilità di modulare la densità di reticolazione dell’idrogelo per ottenere il miglior compromesso tra resistenza meccanica e flessibilità, l’integrità strutturale nel tempo e la capacità di assorbire fluidi biologici o trattenere l’umidità. Inoltre, ne è …

Neuroprotective effect of a new Insulin-Nanogel system

Nanogels (NGs) have a great potential in the development of “smart” nanocarriers for (bio)molecular drugs and contrast agent for bioimaging. They are formed by physically or chemically crosslinked polymer networks, characterized by a large and flexible surface available for multivalent bioconjugations. NGs can be produced with high yields and through-puts by pulsed electron-beam irradiation of dilute aqueous solutions of water-soluble biocompatible polymers. In this work, a carboxyl functionalized nanogel system (NG), generated by pulsed e-beam irradiation of a semi-dilute poly(N-vinyl pyrrolidone) (PVP) aqueous solution in the presence of acrylic acid, with an average diameter in the 60-70…

Oligonucleotide-decorated carboxyl-modified PVP nanogels: a new platform for diagnosis and gene-therapy.

Nanogels, or nanoscalar chemically crosslinked polymer networks, were generated by simultaneous crosslinking of Poly(N-vinyl pyrrolidone) (PVP) and grafting of acrylic acid (AA) monomer through e-beam irradiation of their aqueous solutions. The yield of the process is very high and no separation or complex purification procedures are required since no recourse to surfactants or organic solvents is made. The administered irradiation dose (40 kGy) imparts also sterility to the obtained nanogels in the form of aqueous dispersions. Control of particle size and size-distribution can be achieved by proper selection of the irradiation conditions. In particular, we obtained nanogel variants with av…

Pulsatile protein release and protection using radiation-crosslinked polypeptide hydrogel delivery devices

Abstract In the recent years recombinant technology has identified numerous protein based therapeutics. Their effective delivery, though, can be challenging due to the poor stability of most proteins along their pathway to the target site in the body. Hydrogels have been identified as good candidates for protein encapsulation and delivery thanks to both material and manufacturing process advantages. In this work we propose high energy irradiation as a synthetic methodology of choice to engineer hydrogel-based delivery devices for encapsulation and pulsatile release of proteins, triggered by pH, and for prevention of their denaturation when encapsulated. In particular, maleic anhydride funct…

New insights on the mechanism of PVP nanogels radiation synthesis

In this work, the H2O2 build-up for several system compositions and irradiation conditions was investigated, by using the Ghormley triiodide method. Interestingly, the application of the method has revealed the occurrence of two concurrent reactions, the expected one responsible for the I3 - production (by reaction with the H2O2 formed upon irradiation) and one that is responsible for I3 - consumption. Both the concentrations of I3 - -forming and I3 - -consuming species are dose-dependent and polymer concentration-dependent. The kinetic study of the two reactions and some further experiments carried out with model molecules will be described. We believe that the results of this study can of…

Electrically conductive hydrogel composites made of polyaniline nanoparticles and poly(N-vinyl-2-pyrrolidone)

Abstract A novel electrically conductive composite material, consisting of polyaniline (PANI) nanoparticles dispersed in a polyvinyl pyrrolidone (PVP) hydrogel, was prepared ‘in situ’ by water dispersion polymerisation (DP) of aniline using PVP as steric stabiliser, followed by γ-irradiation induced crosslinking of the PVP component. Conversion yield of aniline into PANI particles was determined via HPLC and gas chromatography, while structural confirmation of the synthesised polymer was sought by FTIR. Morphology and dimensions of PANI particles into the coloured, optically transparent hydrogel was determined by electronic microscopy; moreover, swelling behaviour of composite hydrogels in …

From Small Peptides to Large Proteins against Alzheimer'sDisease.

Alzheimer’s disease (AD) is the most common neurodegenerative disorder in the elderly. The two cardinal neuropathological hallmarks of AD are the senile plaques, which are extracellular deposits mainly constituted by beta-amyloids, and neurofibrillary tangles formed by abnormally phosphorylated Tau (p-Tau) located in the cytoplasm of neurons. Although the research has made relevant progress in the management of the disease, the treatment is still lacking. Only symptomatic medications exist for the disease, and, in the meantime, laboratories worldwide are investigating disease-modifying treatments for AD. In the present review, results centered on the use of peptides of different sizes invol…

Radiation-engineered multifunctional nanogels: a versatile platform with theranostic capabilities for cancer

Under a rational desing, combining biologically active molecules, ligand to specific cell receptors and fluorescent, radioactive or paramagnetic labels into a single nano-object can bride the unique properties of the individual components and impruve conventional sensing, imaging and therapeutic efficaces.

POLYMER ELECTROSPUN NANOFIBERS AS INTERLEAVES FOR ENANCHEMENT OF CFRP LAMINATES DELAMINATION RESISTANCE

Electrospinning process is a technique to produce nanoscale fibers that has evinced more interest in recent years due to its versatility and potential for applications in several applications. The mall size and the concomitant ultra-high specific surface area of electrospun nanofibers make them suitable for several applications, such as tissue engineering, biosensors, filtration and advanced polymer composites (1). In particular for carbon fiber reinforced polymers (CFRPs) the huge specific surface area of electrospun nanofibers results in very large interfacial area between nanofibers and polymer matrix and therefore leads to substantial improvement of fiber-matrix interfacial interactions…

Temperature-induced self-assembly of degalactosylated xyloglucan at low concentration

Xyloglucan is a natural polysaccharide having a cellulose-like backbone and hydroxyl groups-rich side-chains. In its native form the polymer is water-soluble and forms gel only in presence of selected co-solutes. When a given fraction of galactosyl residues are removed by enzymatic reaction, the polymer acquires the ability to form a gel in aqueous solution at physiological temperatures, a property of great interest for biomedical/pharmaceutical applications. This work presents data on the effect of a temperature increase on degalactosylated xyloglucan dispersed in water at concentration low enough not to run into macroscopic gelation. Results obtained over a wide interval of length scales …

Radiation-induced synthesis of nanogels: advances in research and applications

From their first appearance in 1969, when Schnagel and Borwardt reported the radiochemical synthesis of poly(ethylene oxide) microgels by gamma-irradiation, the possibility of generating crosslinked micro- and nanoparticles from ”pure” aqueous solutions of macromolecules, have triggered the imagination of material scientists on the search for ”clean” processes and products for biomedical applications. Thanks to the seminal studies of Rosiak and co-workers, who have clarified, both experimentally and mechanistically, the key role of intra-molecular crosslinking in controlling the particle size, the scientific community has now a powerful tool to design and manufacture radiation-synthetized n…

Hydrothermal ageing of radiation cured epoxy resin-polyether sulfone blends as matrices for structural composites

Abstract The hydrothermal ageing of epoxy–thermoplastic blends, used as matrices for carbon fibre composites, cured by electron beam, has been studied. Two different thermoplastic percentages have been adopted. A suitable choice of both curing process and formulation parameters allows to carry out irradiation at mild temperature with several advantages, coming from a “non thermal” process, for both the final properties of the materials and the environment. Nevertheless the occurring of vitrification phenomena needs the use of a short thermal treatment after irradiation on the already solid materials, in order to complete the cure reactions. Radiation cured epoxy based matrices have been sub…

Radiation Engineering of Xyloglucan Hydrogels

Xyloglucans (XGs) are interesting substrates for the production of scaffolds for tissue engineering, drug delivery depots and hydrogel dressings, thanks to their ability to gel in appropriate conditions, such as in the presence of hydro-alcoholic solvents or by addition of sugar molecules. Due to their natural source, they are characterized by high average molecular weights and broad molecular weight distributions. High energy irradiation is a suitable tool to reduce polysaccharides molecular weight without a dramatic alteration of the polymer chemical structure and gelation ability. In this work, the effect of the radiation dose on the molecular weight of a XG derived from Tamarind seeds i…

Water diffusion and swelling stresses in ionizing radiation cured epoxies as matrices for carbon fiber composites

Cross-linking polymerization initiated by high energy radiation is a very attractive technique for the production of high performance composite materials. This method in fact offers many advantages compared to conventional thermal curing processes, due to the possibility to operate at mild temperature and in short time, limiting both energy and time consuming [1-2]. High performance composite materials mainly consist of epoxy resins as matrix and carbon fibers as reinforce, due to their excellent properties in terms of thermal and mechanical resistance. An important requirement of such systems for structural applications is their ability to maintain the properties within a fixed range durin…

Insulin Nanogel as New Strategy for the Treatment of Alzheimer’s Disease

A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signaling are involved in brain cognitive functions and their dysfunction is implicated in neuronal degeneration associated with Alzheimer's disease (AD). Thus, the administration of insulin to the brain could be a strategy for the prevention and treatment of AD disease. With this aim, we have designed, synthesized and characterized a nanogel system (NG) that can be used as substrate for the conjugation of insulin and/or fluorescent molecules relevant for their characterization. In particular, a carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system, has been produced by ionizing radiation starting from th…

Functional hydrogels containing polyaniline nanoparticles through e-beam irradiation

Periodically nanostructured hydrogels for ethanol vapors sensing

Chemical sensing using optics has been under extensive research all over the world during last decades and many optical chemical sensors are nowadays finding increasing applications in industry, environmental monitoring, medicine, biomedicine and chemical analysis. These optical sensors can be based on various optical principles, such as absorbance, reflectance or transmittance, luminescence and fluorescence, covering different regions of the spectrum (UV, visible, IR, NIR). Optical chemical sensors have several advantages over conventional electricity-based sensors, in terms of selectivity, immunity to electromagnetic interference, higher sensitivity, and they are also relatively inexpensi…

Biocompatibility, hemocompatibility and antimicrobial properties of xyloglucan-based hydrogel film for wound healing application.

Crosslinked xyloglucan-poly(vinyl alcohol) based hydrogel films are interesting materials for wound healing applications. This work focuses on the hydrolytic degradation and consequent morphological modification of a XG-PVA film and on its interaction with cells, blood, bacteria. Biocompatibility of the film was assessed in vitro by investigating different aspects, such as cell viability, oxidative stress level, mitochondrial dysfunction and specific stress biomarkers. Partial adhesiveness was demonstrated by performing different attaching assays and phalloidin staining. Hemocompatibility of XG-PVA film after interaction with blood was evaluated by using a multi-parametric approach, includi…

κ-Carrageenan and PVA blends as bioinks to 3D print scaffolds for cartilage reconstruction.

3D printing of polymeric scaffolds and autologous stem cells is a promising tool for damaged facial cartilage reconstruction surgeries. To this end, suitable bioinks are needed to generate scaffolds with the required morphological and functional features. We formulated hydrogel bioinks using k-Carrageen (kC) and poly(vinyl alcohol) (PVA) in three different weight ratios. The kC gives the systems the ability to undergo rapid sol-to-gel transitions upon cooling from 60 °C and above to body temperature, while the PVA is used as rheology modifier and porogen. The latter is crosslinked after molding or printing by freeze-thaw cycling for 1 day (FT1) or 5 days (FT5). To select the most suitable f…

Large-scale Radiation Manufacturing of Hierarchically Assembled Nanogels

Nanogels (NGs), or small particles formed by physically or chemically crosslinked polymer networks, represent a niche in the development of “smart” nanoparticles for drug delivery and diagnostics. They offer unique advantages over other systems, including a large and flexible surface for multivalent bio-conjugation; an internal 3D aqueous environment for incorporation and protection of (bio)molecular drugs; the possibility to entrap active metal or mineral cores for imaging or phototherapeutic purposes; stimuli-responsiveness to achieve temporal and/or site control of the release function and biocompatibility. The availability of inexpensive and robust preparation methodologies is at the ba…

Macromolecular design and preparation of nanogels as pharmaceutical carriers

Internal properties of "ultra clean" hydrogels synthesized via e-beam irradiation through absorption and luminescence spectroscopy

Synthesis of polymer nanogels by electro-Fenton process: investigation of the effect of main operation parameters

Recently, electro-Fenton (EF) process has been shown as a promising, facile, effective, low cost and environmentally-friendly alternative for synthesizing polymer nanogels suitable as biocompatible nanocarriers for emerging biomedical applications. Here, the electrochemically-assisted modification of poly(vinylpyrrolidone) (PVP) by EF process was studied to assess the role of key operation parameters for a precise modulation of polymer crosslinking and its functionalization with [sbnd]COOH and succinimide groups. The dimensions of the nanogels, in terms of hydrodynamic radius (Rh) and weight-average molecular weight (Mw), can be tuned up by controlling the electrolysis time, current density…

Moringa oleifera Leaf Powder as Functional Additive in Cookies to Protect SH-SY5Y Cells

The aim of this work is the evaluation of the addition of Moringa leaf powder (MLP) in cookies in terms of antioxidant properties, dough processability and sensorial properties of the cookies. The total content of biophenols and flavonoids in MLP was detected and the identification of the bioactive molecules was performed by HPLC-ESI-TOF-MS measurements, before and after oven treatment at 180 ◦C for 20 min. After a preliminary evaluation of the MLP water soluble fraction (MLPsf) cytotoxicity, its protective effect against an oxidative injury induced in the SH-SY5Y cells was assessed. Data evidence that the bioactive molecules present in MLPsf are effective in preventing ROS production and i…

UN NUOVO METODO PER OTTENERE FILM FLESSIBILI EAA-PANI

Numerical simulations of the mechanical characteristics of glass fibre reinforced C-profiles

A mechanical characterisation analysis on pultruded glass fibre reinforced C-shaped profiles, developed as modular construction elements to assemble fastening systems, such as doors, window frames and shutters is presented. The key idea is to perform the analysis, and all the related identification procedures of the material parameters, via a coupled approach, based on a limited number of standard laboratory tests and on the numerical finite element simulations of the same tests. The proposed approach allows one to identify all those material parameters which are difficult to detect, by means of simple laboratory experiments on specimens that are extracted from commercial products. It also …

TEMPERATURE-TRIGGERED MACROSCOPIC GELATION OF IRRADIATED XYLOGLUCANS FOR BIOMEDICAL APPLICATIONS

Optical characterization of polystyrene direct opals and of inverse-opal hydrogels

Structural adhesive joints for transport applications

Influence of nanoporous structure on mechanical strength of aluminium and aluminium alloy adhesive structural joints

The influence of surface treatments on the mechanical strength of adhesive joints was investigated. The attention was focused on AA2024 alloy because it is extensively used in both the automotive and aerospace industries. Adhesive joints fabricated with pure aluminium were also investigated in order to evidence possible differences in the surface features after identical treatments. Before joining with a commercial epoxy adhesive, metal substrates were subjected to different kinds of treatment and the surfaces were characterized by SEM analysis. The formation of a microporous surface in the AA2024 alloy, upon etching and anodizing, is discussed on the basis of the role of the intermetallic …

Laser surface treatments for adhesion improvements of aluminium alloys structural joints

Sintesi di materiali avanzati mediante radiazioni ionizzanti

Micro- and Nano- polymer based composites for novel generation bio-medical materials

Gadolinium-chelating nanogels as MR contrast agents specifically targeting tumor cells

Aims and objectives Methods and materials Results Conclusion Personal information References

In-situ gelling xyloglucan formulations as 3D artificial niche for adipose stem cell spheroids.

Abstract Three-dimensional spheroidal cell aggregates of adipose stem cells (SASCs) are a distinct upstream population of stem cells present in adipose tissue, with enhanced regeneration properties in vivo. The preservation of the 3D structure of the cells, from extraction to administration, can be a promising strategy to ensure optimal conditions for cell viability and maintenance of stemness potential. With this aim, an artificial niche was created by incorporating the spheroids into an injectable, in-situ gelling solution of partially degalactosylated xyloglucan (dXG) and an ad hoc formulated culture medium for the preservation of stem cell spheroid features. The evolution of the mechani…

Facile crosslinking of poly(vinylpyrrolidone) by electro-oxidation with IrO2-based anode under potentiostatic conditions

Abstract: The modification of polymer architectures by reaction with chemically adsorbed hydroxyl radicals has been thoroughly investigated by electrolyzing dilute aqueous solutions of the biocompatible polymer poly(vinylpyrrolidone) (PVP), using an undivided electrolytic cell with a Ti/IrO2–Ta2O5(DSA®) anode. Several electrolyses were performed to assess the influence of the applied potential, the circulated charge and the PVP concentration, which was always kept low to avoid chain overlapping. From the results obtained, it can be concluded that the electro-oxidation of PVP solutions using a cheap anode is an effective method to crosslink initially isolated polymer chains, eventually incre…

Carbon Fiber Composites Cured by γ-Radiation-Induced Polymerization of an Epoxy Resin Matrix

The use of ionizing radiation in order to initiate polymerization of suitable monomers has found increased interest in the last two decades due to its several advantages. In this work, carbon fiber composites through gamma radiation polymerization of epoxy matrices have been produced for aerospace and advanced automotive applications. Composite samples were produced by irradiation at room temperature using different radiation doses and, as reference, thermal curing of the same epoxy resin formulations was also carried out. Furthermore, some irradiated samples were subjected to postirradiation thermal curing to complete the polymerization reactions. The properties of the cured materials were…

Neurological Consequences, Mental Health, Physical Care, and Appropriate Nutrition in Long-COVID-19.

SARS-CoV-2 pandemic has caused a collapse of the world health systems. Now, vaccines and more effective therapies have reversed this crisis but the scenario is further aggravated by the appearance of a new pathology, occurring as SARS-CoV-2 infection consequence: the long-COVID-19. This term is commonly used to describe signs and symptoms that continue or develop after acute infection of COVID-19 up to several months. In this review, the consequences of the disease on mental health and the neurological implications due to the long-COVID are described. Furthermore, the appropriate nutritional approach and some recommendations to relieve the symptoms of the pathology are presented. Data colle…

Ionizing radiation induced curing of epoxy resin for advanced composites matrices

Abstract The radiation curing of an epoxy monomer in the presence of an iodonium salt, as photo initiator, is studied. Systems with different concentrations of photo initiators have been polymerized via both gamma rays and e-beam, at various dose rates. The aim of this work is to investigate how the photo initiator concentration and the irradiation dose rate affect the temperature of the systems during curing and how the different thermal histories influence the dynamic mechanical thermal properties of the obtained materials.

Novel epoxy formulations for high energy radiation curable composites

Abstract It has been widely recognised that high energy radiation can be effectively applied to the cure of epoxy resins in applications as composite matrices or structural adhesives with improvements in product quality and/or reduction in production costs. In the presence of suitable initiators, polymerisation of epoxies occurs via cationic mechanism, thus restricting the choice of the resin system components to species which do not contain electron donor groups. The present investigation is aimed to identify suitable co-monomers to be formulated with an epoxy resin, resulting in different cure reaction kinetics and application properties of the cured resin. In particular, four different a…

Novel Gamma-crosslinked Hydrogels for Intelligent Release of Actives

Electrochemical treatments of aluminium alloys surfaces: a way to improve the performance of structural adhesives

Synthetic and natural polymer nanoparticles as bio-imaging and therapeutic agent vectors

Dual Stimuli-Responsive Polysaccharide Hydrogels Manufactured by Radiation Technique

Featured Application Stimuli-responsive hydrogels encompassing biobased polymers are anticipated for utilization in various fields, starting from drug delivery systems through temporal actuators and water reservoirs to biodegradable microelements and nutrient delivery depots. This paper describes the results of the radiation-induced crosslinking of polysaccharides modified with hydroxypropyl and carboxymethyl functional groups, hydroxypropylcellulose (HPC) and carboxymethylcellulose (CMC), respectively, without and with poly(ethylene glycol) diacrylate (PEGDA) as a crosslinking agent, to obtain dual stimuli-responsive hydrogels. The gels were characterized in terms of water uptake and gel f…

Radiation engineering of functional biomaterials: from smart hydrogels to theragnostic nanodevices

Durability behaviour of aluminium alloy joints bonded with epoxy adhesives

High-energy radiation process, a "facile" and "versatile" approach to obtain PVP-graft- AA nanogels

Poly(N-vinylpyrrolidone)-grafted-acrylic acid biocompatible nanogels (NGs) were prepared using an exiting industrial-type electron accelerator and setups, starting from semi-dilute aqueous solutions of a commercial PVP and the acrylic acid monomer. As a result, NGs with tunable size and structure can be obtained quantitatively. Sterility was also imparted at the integrated dose absorbed. The chemical structure of the NGs produced was confirmed through Fourier Transformer Infrared Spectroscopy (FT-IR). The molecular and physico-chemical properties of NGs, such as the hydrodynamic dimensions and surface charge densities, for various polymer and monomer concentrations in the irradiated solutio…

Electrical properties of γ-crosslinked hydrogels incorporating organic conducting polymers

Abstract Hydrogel composites containing nanoparticles of the protonated emeraldine form of polyaniline (PANI-PE) have been synthesised by γ-irradiation, using either polyvinyl pyrrolidone (PVP) or polyvinyl alcohol (PVA) as steric stabilisers. Swelling behaviour of both hydrogels is reported, together with an electrical characterisation of composites, before and after gel network formation, performed by cyclic voltammetry and impedance spectroscopy. Similarities and differences between the two composite systems are discussed.

Sintesi e caratterizzazione di idrogeli biocompatibili stimolo-sensibili

The influence of the rubber carboxyl functionality on the processability and properties of solid rubber modified epoxy mixtures

A high molecular weight, carboxyl functionalised solid rubber was added to an epoxy resin-aromatic amino system developed for autoclave curing of honeycomb core composite structures. The achievement of an optimal balance of viscous flow and viscoelasticity of the resin, by controlling the nature and extent of cross-linking of the functionalised rubber, was proposed as a route to void-free honeycomb skins. The aim of the present investigation is to understand how the concentration of carboxylic groups of the rubber, prereacted with one of the epoxy monomers, affects the matrix resin flow properties. The concentration of carboxyl groups was changed by reacting them with a monofunctional epoxy…

Polymeric Nanogels: Nanocarriers For Drug Delivery Application.

The application of nanotechnology to medicine has enabled the development of functionalised nanoparticles that, acting as carriers, can be loaded with drugs or genetic material to be released with a controlled mechanism in specific districts of the organism. Even though nanomedicine is a relative new branch of science, many type of nanocarriers for drug delivery have been developed over the past 30 years, such as liposomes, dendrimers, quantum dots, solid lipid nanoparticles, viruses and virus-like nanoparticles as well as a wide var iety of polymeric nanoparticles. Among these last, in our opinion, nanogels deserve a special attention. Nanogels are nanoscalar polymer networks, with a tende…

Synthesis and characterization of a new insulin conjugated nanogel for biomedical application

Insulin, a metabolic hormone involved in glucose metabolism, plays also a neuroprotective role in the central nervous system being able to revert the cytotoxic processes induced by Aβ42,a peptide involved in Alzheimer's disease. To reach the brain insulin have to across the BBB therefore an additional delivery strategy results to be necessary. For these aim we performed an insulin conjugated nanogels (NGs-In). Nanogels (NGs) have a great potential in the development of “smart” nanocarriers for (bio)molecular drugs and contrast agent for bioimaging. They are formed by physically or chemically crosslinked polymer networks, characterized by a large and flexible surface available for multivalen…

Toughened matrices for advanced carbon fibre composites obtained through e-beam curing of two different epoxy-thermoplastic blends

Preparazione di nanoparticelle di xiloglucano degalattosilato per applicazioni biomediche

Cure behaviour of epoxy resin matrices for carbon fibre composites

The cure behaviour of two resin formulations (with high and low curing agent content respectively) of an epoxy resin system, used as matrix for carbon fibre composites, was studied through calorimetric analysis. The aim of this work is to investigate the kinetics of this specific epoxy system in order to be able to choose a proper set of processing parameters which will give good composite material properties. The shape of the conversion curves gives evidence of the differences in the cure kinetics of the two systems. Furthermore, the values of the activation energies were determined both for formulation in the conversion range where vitrification occurs, following a phenomenological approa…

Crosslinking of poly(vinylpyrrolidone) activated by electrogenerated hydroxyl radicals: a first step towards a simple and cheap synthetic route of nanogel vectors

A facile electrosynthesis route for the preparation of polymer nanogels based on the in situ production of hydroxyl radicals is reported for the first time. Electro-Fenton process with continuous H2O2 electrogeneration and Fe2+ regeneration performs better than electro-oxidation with a boron-doped diamond or dimensionally stable anode for promoting crosslinking of poly(vinylpyrrolidone). Keywords: Electrogenerated hydroxyl radicals, BDD, DSA, Electro-Fenton, Polymer modification, Nanogel

Ionizing radiation curing of epoxy based blends in order to produce high performance composites

Temperature-responsive degalactosylated xyloglucans as nanocarriers for the sustained release of hydrophobic drugs

Inorganic/organic hybrid nanoparticles synthesized in a two-step radiation-driven process

In this work, we have synthesized inorganic-organic hybrid nanoparticles via radiation synthesis of inorganic nanoparticles (Ag and CeO2) in aqueous dispersions containing radiation-synthesized poly(N-vinyl pyrrolidone) (PVP) nanogels (NG). The experiments show that there are strong interactions between the inorganic precursors (Ag+ and Ce3+) and the nanogel prior to irradiation. The two hybrid systems (Ag/NG and CeO2/NG) were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD confirms the formation of crystalline Ag and CeO2. TEM reveals that the inorganic nanoparticles are evenly distributed in/on the nanogel. Both XRD and TEM show that size of the…

CONTROLLED DELIVERY OF WATER-INSOLUBLE ACTIVE INGREDIENTS IN AIR FROM HYDROGEL MATRICES

Structure of e-beam sculptured poly(N-vinylpyrrolidone) networks across different length-scales, from macro to nano

Abstract Study of macromolecular structure and dynamics of networks formed by pulsed electron-beam irradiation of poly(N-vinyl pyrrolidone) (PVP) aqueous solutions, at relatively low energy per pulse and across different concentration regimes, provides the basis for the understanding of a new generation of functional nanostructures. Networks are the result of the follow–up reactions initiated by a continuous series of electron pulse-generated hydroxyl radicals, which may have a different fate at the variance of polymer concentration. Different spectroscopic techniques, FT-IR, 13 C { 1 H} CP-MAS NMR and Raman, applied to characterize the formed networks, describe a profound modification of t…

Radiation-Engineered Functional Nanoparticles in Aqueous Systems.

Controlled synthesis of nanoscalar and nanostructured materials enables the development of novel functional materials with fine-tuned optical, mechanical, electronic, magnetic, conductive and catalytic properties that are of use in numerous applications. These materials have also found their potential use in medicine as vehicles for drug delivery, in diagnostics or in combinations thereof. In principle, nanoparticles can be divided into two broad categories, organic and inorganic nanoparticles. For both types of nanoparticles there are numerous possible synthetic routes. Considering the large difference in nature of these materials and the elementary reactions involved in the synthetic rout…

Radiation Engineering of Multifunctional Nanogels

Nanogels combine the favourable properties of hydrogels with those of colloids. They can be soft and conformable, stimuli-responsive and highly permeable, and can expose a large surface with functional groups for conjugation to small and large molecules, and even macromolecules. They are among the very few systems that can be generated and used as aqueous dispersions. Nanogels are emerging materials for targeted drug delivery and bio-imaging, but they have also shown potential for water purification and in catalysis. The possibility of manufacturing nanogels with a simple process and at relatively low cost is a key criterion for their continued development and successful application. This p…

Biodistribution of Insulin-Nanogels in Mouse: A Preliminary Study for the Treatment of Alzheimer's Disease

A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signaling are involved in brain cognitive functions and their dysfunction is implicated in Alzheimer's disease (AD) neurodegeneration. Thus, administration of insulin could be a strategy for AD treatment. For this aim we have designed, synthesized and characterized a nanogel system (NG) that has been conjugated to insulin molecules (NG-In) to deliver the protein into the brain, as a tool for the development of a new therapy against AD. In our preclinical study in mice, intraperitoneal injection of fluorescent-labeled NG has allowed to determine the biodistribution of NG vs time in the whole body and its clearance th…

Oligonucleotides-decorated-poly(N-vinyl pyrrolidone) nanogels for gene delivery

Pulsed electron-beam irradiation of a semi-dilute poly(N-vinyl pyrrolidone) (PVP) aqueous solution in the presence of acrylic acid has led to a carboxyl functionalized nanogel system. Nanoparticles hydrodynamic size and surface charge density, in water and as a function of pH, were investigated by dynamic light scattering and laser doppler velocimetry, respectively. Nanogels (NGs) were proved not to be cytotoxic at the cellular level. Indeed, they rapidly bypass the cellular membrane to accumulate in specific cell portions of the cytoplasm, in the perinuclear area. The availability of pendant carboxyl groups on the crosslinked PVP NGs core prompted us to attempt their decoration with a sing…

Radiation-Engineering of All Plastic Nanocomposite Films

In recent years, polymer nanocomposites have fascinated scientists, engineers and industrialists on the premise that the creation of new and more performing polymeric materials is possible by the combination of different building blocks with controlled dimensions at the nanoscale. Unfortunately, uniform dispersion of the hetero-phase domains within the plastic matrix or on its surface often fails due to the unfavorable thermodynamics, thus resulting in migration and irreversible aggregation phenomena. In-situ generation of a dispersed hetero-phase within the same polymer matrix or in its precursors increases the chances of achieving a better control of morphology by eliminating the often cr…

A new route for the preparation of flexible skin–core poly(ethylene-co-acrylic acid)/polyaniline functional hybrids

Abstract Surface modification of polymeric films is a way to obtain final products with high performance for many specific and ad hoc tailored applications, e.g. in functional packaging, tissue engineering or (bio)sensing. The present work reports, for the first time, on the design and development of surface modified ethylene–acrylic acid copolymer (EAA) films with polyaniline (PANI), with the aim of inducing electrical conductivity and potentially enable the electronic control of a range of physical and chemical properties of the film surface, via a new “grafting from” approach. In particular, we demonstrate that PANI was successfully polymerized and covalently grafted onto flexible EAA su…

Epoxy resin based matrices for advanced composites cured by ionizing radiation. Study of the influence of process parameters on final properties

Reactive blending of functionalized acrylic rubbers and epoxy resins

A high molecular weight acrylonitrile/butadiene/methacrylic acid (Nipol 1472) rubber is chosen to control processability and mechanical properties of a TGDDM (tetra glycidyl diphenyl methane) based epoxy resin formulation for aerospace composite applications. The physical blend of rubber and epoxy resin, achieved by dissolution of all the components in a common solvent, forms a heterogeneous system after solvent removal and presents coarse phase separation during cure that impairs any practical relevance of this material. A marked improvement of rubber-epoxy miscibility is achieved by reactive blending ('pre-reaction') the epoxy oligomer with the functional groups present in the rubber. The…

Sintesi di nanogeli per la veicolazione di insulina al cervello: una strategia per il trattamento della malattia di Alzheimer

I nanogeli sono nanoparticelle polimeriche reticolate idrofile. La struttura polimerica del nanogelo permette la coniugazione di molecole che possano esplicare azioni terapeutiche, diagnostiche e di indirizzamento attivo su siti bersaglio. Le caratteristiche di flessibilità e conformabilità del nanogelo, e delle sue maglie, ne favoriscono l’attraversamento delle barriere biologiche, l’interazione di eventuali ligandi esposti sulla superfice con i recettori target, un’azione protettiva nei confronti del principio attivo incorporato. L’irraggiamento con radiazioni ionizzanti di soluzioni acquose di polimeri è una metodologia sintetica interamente “water-based”, che garantisce rese elevate e c…

Insulin-nanogels: preliminary study in mouse for the treatment of Alzheimer's disease

A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signalling are involved in brain cognitive functions and their dysfunction is implicated in Alzheimer’s disease (AD). Thus, administration of insulin could be a strategy for AD treatment. For this aim we have designed, synthesized and characterized a nanogel system (NG) that has been conjugated to insulin molecules (NG-In) (1) as new therapeutic approach against AD. In our preclinical studies in mice, intraperitoneal injection of fluorescent-labeled NG has allowed to determine the biodistribution of NG vs time in the whole body and its clearance through the kidneys and bladder. Furthermore, we have observed that mic…

Xyloglucan-based hydrogel films for wound dressing: Structure-property relationships

Thin xyloglucan-based hydrogel films have been synthetized and characterized in the prospect of producing wound dressings. Polyvinyl alcohol (PVA) and glycerol (Gro) were added to have an optimal combination of softness, conformability and resilience. Physical hydrogels have been transformed into permanent covalent hydrogels by reaction with glutaraldehyde (GA). Network structure-process-property relationships are discussed on the account of the results of several complementary characterizations: FTIR, rheology, thermal analysis, morphological analysis, moisture retention and swelling measurements. Selected formulations were also subjected to preliminary in vitro cytotoxicity tests. The phy…

Chemical design of flexible skin-core poly(ethylene-co-acrylic acid)/nanostructured polyaniline hybrids

In-situ polymerization of polyaniline in radiation functionalized polypropylene films

Abstract In-situ generation of a nanodispersed conductive polymer within a polypropylene matrix has been pursued in order to obtain flexible, conductive films. Radiation grafting of acrylic acid to polypropylene (PP) has been applied to insert carboxyl functionalities on PP. The radiation-grafted films have been further derivatized with a variety of diamines and used as substrates for in-situ chemical oxidative polymerization of polyaniline (PANI). PANI grows as a thin skin from the surface of the film as well as an interpenetrated network in its interiors. Evidence of chemical attachment of PANI to PP has been sought by performing FTIR and XPS analyses after extraction of the unbound polym…

Temporal control of xyloglucan self-assembly by radiation-induced degradation

Xyloglucan is a natural polysaccharide present as storage material in seeds and structural materials in the primary cells walls of higher plants. Xyloglucan from tamarind seed is composed of B(1,4)-D-glucan backbone, partially substituted by a-(1,6)-linked xylose units, some of which are B-D-galactosylated at O-2. In its native form the polymer is water-soluble and forms gel in the presence of moderate amounts of alcohols. When a given fraction of galactosyl residues are removed, the polymer acquires the ability to form gels in aqueous solution at physiological temperatures, a property of great interest for biomedical/pharmaceutical applications. Gelation on increasing temperature can be as…

Structural investigation of e-beam cured epoxy resins through solid state NMR

Abstract In this paper the network structure of e-beam cured DGEBF based epoxy resins is investigated. Two epoxy systems, having different reactivity and cured in different process conditions, were analyzed through solid state NMR spectroscopy. The analysis shows that the more reactive system has higher cross-linking density and higher uniformity of network distribution. Similar information were obtained, in a previous work, on the same systems through dynamic mechanical thermal analysis. It is worth noting that unlike DMTA tests, which interfere with the molecular structure of the analyzed material, due to the heating during the analysis itself, more reliable information, without any artef…

Nuovi materiali nanocompositi a base di idrogeli e polimeri conduttori per l’elettronica molecolare

Radiation processing: a versatile methodology to tune the structure of polymeric materials

RFID epidermal sensor including hydrogel membranes for wound monitoring and healing

This contribution experimentally demonstrates for the first time the feasibility of joint application of passive UHF RFID technology and hydrogel membranes to fabricate smart plasters able to gather and remotely transmit information on the conditions of human skin. In particular, this intelligent plaster is sensitive to temperature and fluid uptake/release and could open interesting scenarios in wound healing monitoring and drug delivery.

E-beam crosslinked nanogels conjugated with monoclonal antibodies in targeting strategies

Abstract Poly(N-vinyl pyrrolidone)-based-nanogels (NGs), produced by e-beam irradiation, are conjugated with monoclonal antibodies (mAb) for active targeting purposes. The uptake of immuno-functionalized nanogels is tested in an endothelial cell line, ECV304, using confocal and epifluorescence microscopy. Intracellular localization studies reveal a faster uptake of the immuno-nanogel conjugate with respect to the ‘bare’ nanogel. The specific internalization pathway of these immuno-nanogels is clarified by selective endocytosis inhibition experiments, flow cytometry and confocal microscopy. Active targeting ability is also verified by conjugating a monoclonal antibody which recognizes the αv…

Photonic crystal hydrogel films responsive to ethanol vapors

Gamma irradiation of xyloglucans and hydroxypropyl cellulose in dry and humid solid state to tune molecular weight distribution

Polymer based nanocomposites for novel generation greener material

Development and characterization of xyloglucan-poly(vinyl alcohol) hydrogel membrane for wireless smart wound dressings

Research which addresses advanced wound management can contribute to the needs of modern healthcare, especially in situations that require continuous monitoring, analysis, responsive therapeutic treatments and data recording. The development of “smart” bandages and dressings that can remotely monitor relevant parameters for the wound healing process without a hospital intervention can be very useful tools for patients and physicians and for advancing the understanding of the healing process. In the present work, biocompatible xyloglucan/poly(vinyl alcohol) hydrogels are being developed as smart wound dressings that, in addition to the traditional favorable properties of hydrogels as skin ca…

DESIGN AND CHARACTERIZATION OF MUCOADHESIVE SUBLINGUAL FILMS CONTAINING FUROSEMIDE

PROPERTIES OF IONIZING RADIATION CURED POLYMER MATRICES FOR CARBON FIBER COMPOSITES AFTER AGEING DUE TO MOISTURE ABSORPTION AND THERMAL TREATMENT

Radiation synthesis of polyaspartamide functionalised hydrogels for sustained release of fragrances

The aim of the present investigation is to assess the possibility of obtaining a biocompatible material device which is able to deliver oil-soluble fragrances in air over a length of time. Aqueous solutions of polyaspartamide functionalised with glycidyl methacrylate have been cross linked through gamma irradiation in the presence of a lipophilic model fragrance, emulsified prior to irradiation. Two emulsification conditions have been considered at two different concentrations of both fragrance and surfactant in water. Chemical hydrogels have been obtained in correspondence to two irradiation absorbed doses and have been characterised for their solubility properties and swelling ability in …

Temporal control of xyloglucan self-assembly into layered structures by radiation-induced degradation

Partially degalactosylated xyloglucan from tamarind seeds (Deg-XG) is a very appealing biopolymer for the production of in situ gelling systems at physiological temperature. In this work, we observe that the morphology of hydrogels evolves towards high degrees of structural organization with time, yielding to dense stacks of thin membranes within 24 h of incubation at 37 °C. We also explore the possibility offered by gamma irradiation of controlling the time scale of this phenomenon, the final morphology and mechanical properties of the system. Structural and molecular modifications of Deg-XG with dose are investigated by FTIR, dynamic light scattering (DLS) and rotational viscosimetry. The…

Flexible nanoskin-core poly(ethylene-co-acrylic acid) polyaniline hybrids

Studies of network structure and dynamics of e-beam crosslinked PVPs: From macro to nano

Much interest has been paid to develop a variety of radiation-crosslinked hydrated polymeric materials, which swell in water but do not dissolve, as biocompatible materials used for wound healing, drug delivery system, surface-coating material for medically used devices, etc. With the aim of establishing design rules to produce hydrogels of controlled size at the nanoscale and desired internal network structure using conventional electron accelerators and set-ups, here we attempt a description in terms of structural and dynamic properties of polymer networks generated through e-beam irradiation of aqueous solutions of the same model polymer, a commercial grade poly(N-vinyl-pyrrolidone), sub…

High energy radiation cure of resin systems for structural adhesives and composite applications

Abstract Radiation cure polymerisation of a commercial diglycidyl ether of bisphenol F epoxy resin has been achieved using a 60Co irradiation source, compounding the monomer with few percentage of an onium salt catalyst. The cure process has been monitored by a gamma-calorimetric technique and systems irradiated at doses corresponding to different positions in the gamma-calorimetric curve have been characterised via solubility tests and dynamic mechanical torsion analysis. Changes in both the measured gel fractions and tan δ values were associated with the progress of polymerisation and crosslinking reactions and these were dose dependent. Furthermore, systems irradiated at lower doses exhi…

Injectable xyloglucan hydrogels incorporating spheroids of adipose stem cells for bone and cartilage regeneration

Abstract Cartilage or bone regeneration approaches based on the direct injection of mesenchymal stem cells (MSCs) at the lesion site encounter several challenges, related to uncontrolled cell spreading and differentiation, reduced cell viability and poor engrafting. This work presents a simple and versatile strategy based on the synergic combination of in-situ forming hydrogels and spheroids of adipose stem cells (SASCs) with great potential for minimally invasive regenerative interventions aimed to threat bone and cartilage defects. Aqueous dispersions of partially degalactosylated xyloglucan (dXG) are mixed with SASCs derived from liposuction and either a chondroinductive or an osteoinduc…

Ibridi flessibili e conduttivi di poly(etilene-co-acido acrilico)/polianilina con struttura "nanoskin-core"

E-beam irradiation and UV photocrosslinking of microemulsion-laden poly(N-vinyl-2-pyrrolidone) hydrogels for ‘‘in situ’’ encapsulation of volatile hydrophobic compounds

Gelled microemulsions are the subject of considerable scientific and commercial interest. Many efforts are currently devoted to improving their toxicological profile and functioning as biocompatible diffusion barrier for the controlled delivery of hydrophobic compounds. In the present investigation, a non-ionic polymeric surfactant was chosen to generate an oil-in-water microemulsion of a model fragrance in the presence of poly(N-vinyl-2-pyrrolidone) (PVP). The microemulsion was then subjected to either electron-beam or UV-irradiation to induce free-radical crosslinking of PVP at low temperature and in the absence of crosslinking agents, catalysts and initiators. Irradiation conditions with…

Numerical Simulations of Nanogel Synthesis Using Pulsed Electron Beam

In this work, a new method for numerical simulation of the radiation chemistry of aqueous polymer solutions exposed to a sequence of electron pulses is presented. The numerical simulations are based on a deterministic approach encompassing the conventional homogeneous radiation chemistry of water as well as the chemistry of polymer radicals. The multitude of possible reactions in the macromolecular system is handled by allowing for a large number of macromolecular species. The speciation of macromolecular species is done to account for variations in molecular weight, number of alkyl radicals per chain, number of peroxyl radicals per chain, number of oxyl radicals per chain, and number of in…

Epoxy resin-thermoplastic blends as polymer matrices for carbon fiber composites

Hydrothermal aging of carbon reinforced epoxy laminates with nanofibrous mats as toughening interlayers

Electrospun mats have been applied as toughening interlayers in high performance carbon fiber epoxy composites. While the toughening mechanism exerted by the mat at the interface is the subject of several recent studies, no investigations are reported on the aging behaviour of laminates comprising these nanostructured elements. This work investigates the influence of the combined effect of water and temperature (90 °C) on laminates with Nylon 6,6 electrospun membranes placed either at the middle plane only or at each interlayer. The water-uptake behaviour is modelled by a two-stage diffusion model and compared with the behaviour of the neat resin and of the laminate without mats. Interestin…

Understanding generation of multifunctional nanogels in chemical-free e-beam irradation synthesis

Radiation engineered nanogels are the core of very promising theranostic nanodevoces. They can be produced starting from aqueous solutions of chemically inert polymers by pulsed e-beam irradiation.

Nanocarriers to targeted terapy: a goal for biomedical applications.

The reasons for the growing interest in biomaterials for application in the biomedical field are related to need to find alternative and more effective than conventional procedures used in drug treatment of several diseases. The traditional methods of drug delivery has limitations due to the drug’s toxicity in the body. The development of nanocarriers, which can be functionalized and loaded with drugs or genetic material and can be released into the body with a controlled mechanism, was a real goal in the field of biomedical applications. Synthetic hydrogels have found many applications especially in tissue-engineering scaffolds, as carriers for implantable and drug delivery devices. Hydrog…

Internal properties of gamma-irradiated polymeric hydrogels studied by means of fluorescent probes