New copolymers graft of α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide obtained from atom transfer radical polymerization as vector for gene delivery

Abstract New cationic α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) graft copolymers were synthesized by ATRP, using diethylamino ethyl methacrylate (DEAEMA) as monomer for polymerization, yielding polycations (PHEA-pDEAEMA) able to condense DNA. Then, consecutive ATRP conditions were set up on PHEA-pDEAEMA to obtain copolymers containing also hydrophilic chains (PHEA-IB-pDMAEMA-pPEGMA) able to improve biocompatibility of polyplexes and to provide them stealth properties. Agarose gel studies showed that the copolymers effectively condensed plasmid DNA to form polyplexes. Light scattering studies were used to analyze the size and the ζ -potential of these polyplexes, showing that cop…

Biocompatible Polymers and Processing Techniques in Drug Delivery and Tissue Engineering

In situ forming hydrogels of new amino hyaluronic acid/benzoyl-cysteine derivatives as potential scaffolds for cartilage regeneration

A new chemical strategy is described to link ethylenediamino (EDA) groups to primary hydroxyl groups of hyaluronic acid (HA) and the obtained derivatives have been characterized by 1H-NMR and 13C-NMR analyses. Such HA–EDA derivatives have been exploited to control the functionalization degree in benzoyl-cysteine (BC) groups, chosen as moieties able to allow both self-assembling in aqueous media and an oxidative crosslinking. In particular, the kinetics of oxidation of thiol groups in HA–EDA–BC derivatives has been studied in Dulbecco's Phosphate Buffer Solution (DPBS) pH 7.4 by colorimetric assays and rheological measurements. Mechanical properties of chemical hydrogels obtained after oxida…

Nanofibrillar scaffold resists to bile and urine action: experiences in pigs

Biomaterial-based-scaffolds’ functions are to replace anatomical and functional features loss of an injured tissue. They can replace native tissue after their reabsorption. Material and methods. In our experimental procedures we utilized the PHEA-PLA+PCL scaffold in 2 female pigs to assess its resistance to bile and urine. Results. Both pigs survived to surgical procedures. After a month fibres appeared unchanged in term of form and dimension at electronic microscopy. Cells and ECM factors were founded inside the scaffold in a microscopical evaluation. Conclusion. Planar and tubular scaffolds were colonized by cells and extracellular matrix elements. The study conducted on pig suggested tha…

Interpenetrating composite biomaterials of hyaluronic acid derivatives and silk fibroin

Biocompatible hydrogels based on hyaluronic acid cross-linked with a polyaspartamide derivative as delivery systems for epithelial limbal cells.

The aim of this work was to evaluate the potential use of hydrogels based on hyaluronic acid (HA) chemically cross-linked with α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-D,L-aspartamide (PHEA-EDA) as substitutes for the amniotic membrane able to release limbal cells for corneal regeneration. Hydrogels, shaped as films, with three different molar ratios (X) between PHEA-EDA and HA (X = 0.5, 1.0 and 1.5) have been investigated. First, it has been evaluated their swelling ability, hydrolytic resistance in simulated physiological fluid and cell compatibility by using human dermal fibroblasts chosen as a model cell line. Then adhesion studies in comparison with collagen gel, have been pe…

POLYSACCHARIDE-POLYAMINOACID HYDROGEL FILMS FOR POTENTIAL CORNEAL CELL RELEASE

In-situ forming gel-like depot of a polyaspartamide-polylactide copolymer for once a week administration of Sulpiride

Abstract Objectives An in-situ forming gel-like depot, prepared by using an appropriate polyaspartamide-polylactide graft copolymer, has been employed to release in a sustained way sulpiride. Methods α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide-g-polylactic acid (PHEA-g-PLA) has been used as a polymer component. Its physicochemical properties make possible to dissolve it in N-methyl-2-pyrrolidone, with the obtainment of a solution able to form a gel-like depot once injected into a physiological medium. Cell compatibility of PHEA-g-PLA depot has been investigated, using murine dermal fibroblasts as cell model. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazo…

A new hyaluronic acid pH sensitive derivative obtained by ATRP for potential oral administration of proteins

Atom transfer radical polymerization (ATRP) has been successfully employed to obtain a new derivative of hyaluronic acid (HA) able to change its solubility as a function of external pH and then to be potentially useful for intestinal release of bioactive molecules, included enzymes and proteins. In particular, a macroinitiator has been prepared by linking 2-bromo-2-methypropionic acid (BMP) to the amino groups of ethylenediamino derivative of tetrabutyl ammonium salt of HA (HA-TBA-EDA). This macroinititor, named HA-TBA-EDA-BMP has been used for the ATRP of sodium methacrylate (MANa) using a complex of Cu(I) and 2,2'-bipyridyl (Byp) as a catalyst. The resulting copolymer, named HA-EDA-BMP-MA…

Bioactive Scaffolds Based on Amine-Functionalized Gellan Gum for the Osteogenic Differentiation of Gingival Mesenchymal Stem Cells

With the aim to produce a cellularized construct for the guided bone regeneration of dento-alveolar defects, here we produce a porous scaffold using an amine derivative of gellan gum to host gingival mesenchymal stem cells (GMSCs) and allow their osteochondral differentiation. Three derivatives were produced by using the same synthetic procedure, and the viscoelastic properties of their aqueous dispersions were investigated and compared to those of the native polysaccharide to choose the derivative with suitable properties for the scaffold production. Freeze-drying was used to obtain a porous sponge that can be rehydrated with the cells’ suspension to produce an implantable cell containing …

Effect of alkyl derivatization of gellan gum during the fabrication of electrospun membranes

Electrospun nanofibers based on polysaccharides represent a consolidated approach in Tissue Engineering and Regenerative Medicine (TERM) and nanomedicine as a drug delivery system (DDS). In this work, two chemical derivatives of a low molecular weight gellan gum (96.7 kDa) with aliphatic pendant tails were processed by electrospinning technique into non-woven nanofibrous mats. In order to generate spinnable blends, it was necessary to associate poly vinyl alcohol (PVA). The relationships between the physicochemical properties and the processability via electrospinning technique of gellan gum alkyl derivatives (GG-C8 and GG-C12 having a degree of alkyl chain derivatization of 17 mol % and 1…

Hybrid Gold/Silica/Quantum-Dots supramolecular-nanostructures encapsulated in polymeric micelles as potential theranostic tool for targeted cancer therapy

Abstract Efficient theranostic tools are today more and more frequently represented by the nano-sized systems. In this paper, polymeric micelles were produced and exploited to encapsulate both an antitumor drug (Doxorubicin) and gold core–shell quantum dots nanoparticles (Au-SiO2/QDs). α,β-poly(N-hydroxyethyl)- dl -aspartamide (PHEA) was functionalized with lipoic acid (LA), polyethylenglycol (PEG), and folic acid (FA) pendant moieties to obtain a synthetic derivative (PHEA-LA-PEG-FA) able to self assemble in aqueous medium giving rise to the formation of polymeric micelles exposing on their surface both targeting groups (FA) and hydrophilic chains (PEG). The drug carrying ability of PHEA-L…

A Par j1/Par J2-polymeric nanoaggragates as a new tool for allergy vaccination

Interaction Between drug loaded Polyaspartamide-polylactide-polisorbate based micelles and cell membrane models: a calorimetric study

Amphiphilic biodegradable copolymers, for their ability to self-assemble into micelle-like aggregates, with a suitable loading capacity, are of emerging interest for the delivery of water-insoluble drugs. α,β-Poly[(N-hydroxyethyl)-dl-aspartamide] (PHEA) is suitable to obtain amphiphilic graft copolymers. These copolymers can be obtained starting from PHEA-ethylenediamine (PHEA-EDA) which is functionalized with polysorbate 80 (PS₈₀, like targeting residues to the brain) and polylactide (PLA, like hydrophobic chains) in order to obtain polymeric micelles of PHEA-EDA-PS₈₀-PLA potentially useful to release drugs to the central nervous system. In this paper, the interaction and absorption of PHE…

TABLET DI ACIDO IALURONICO FUNZIONALIZZATO CON CATENE IDROFOBICHE PER IL RILASCIO LOCOREGIONALE DI PACLITAXEL

INULIN BASED HYDROGEL FOR ORAL DELIVERY OF FLUTAMIDE: PREPARATION, CHARACTERIZATION AND IN VIVO RELEASE STUDIES

The ability of a hydrogel obtained by crosslinking INUDV and PEGBa to facilitate sustained release of flutamide is examined. The hydrogel is prepared in pH = 7.4 PBS and no toxic solvents or catalysts are used. It is recovered in microparticulate form and its size distribution is determined. Mucoadhesive properties are evaluated in vitro by reproducing gastrointestinal conditions. Flutamide is loaded into the hydrogel using a post-fabrication encapsulation procedure that allows a drug loading comparable to that of market tablets. Drug-loaded microparticles are orally administered to cross-bred dogs and the in vivo study demonstrates their ability to prolong the half-life of the principal ac…

Uptake of silica covered Quantum Dots into living cells: Long term vitality and morphology study on hyaluronic acid biomaterials

Quantum Dots (QDs) are promising very bright and stable fluorescent probes for optical studies in the biological field but water solubility and possible metal bio-contamination need to be addressed. In this work, a simple silica-QD hybrid system is prepared and the uptake in bovine chondrocytes living cells without any functionalization of the external protective silica shield is demonstrated. Moreover, long term treated cells vitality (up to 14 days) and the transfer of silica-QDs to the next cell generations are here reported. Confocal fluorescence microscopy was also used to determine the morphology of the so labelled cells and the relative silica-QDs distribution. Finally, we employ sil…

Ciprofloxacin releasing gellan gum/polydopamine based hydrogels with near infrared activated photothermal properties.

Abstract In this work, with the aim to obtain a wound dressing hydrogel, an amine derivative of gellan gum was crosslinked in the presence of 4arm-polyethylenglycole-vinylsulfone. Through this easy and reproducible chemical procedure, a hydrogel with advanced elastic properties and hydrolytic resistance under physiological conditions was obtained. The incorporation of different quantities of polydopamine in the gelling solutions allows to obtain different hydrogels with marked photothermal properties when irradiated with a laser in the near infrared at 810 nm. The organic nanoparticles, reacting with the amino groups of the polysaccharide derivative, contribute to increase the storage modul…

Polymeric Nanocarriers for Magnetic Targeted Drug Delivery: Preparation, Characterization, and in Vitro and in Vivo Evaluation

In this paper the preparation of magnetic nano- carriers (MNCs), containing superparamagnetic domains, is reported, useful as potential magnetically targeted drug delivery systems. The preparation of MNCs was performed by using the PHEA-IB-p(BMA) graft copolymer as coating material through the homogenization−solvent evaporation method. Magnetic and nonmagnetic nanocarriers containing flutamide (FLU-MNCs) were prepared. The prepared nanocarriers have been exhaustively characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and magnetic measurements. Biological evaluation was performed by in vitro cytotoxicity and cell uptake tests and in vivo biodistribution …

Hyaluronic Acid-g-Copolymers: Synthesis, Properties, and Applications

The aim of this chapter is to review hyaluronic acid (HA) graft copolymers focusing in the description of chemical strategies employed for their synthesis, characterization procedures, and applications in biomedical and pharmaceutical field. Usually biocompatible synthetic polymers and peptides with therapeutic activity are grafted to HA to modify in appropriate way the physicochemical properties of the starting polysaccharide for a specific purpose and at the same time to exploit its biological role, biocompatibility, and targeting ability toward cells with receptors for HA. The use of such HA graft copolymers in the production of nanocarriers or hydrogels for modified drug release and sca…

Biomaterials for Biotechnological and Pharmaceutical application

An asymmetric electrospun membrane for the controlled release of ciprofloxacin and FGF-2: Evaluation of antimicrobial and chemoattractant properties.

Here, an asymmetric double-layer membrane has been designed and fabricated by electrospinning as a tool for a potential wound healing application. A hydrophobic layer has been produced by using a polyurethane-polycaprolactone (PU-PCL) copolymer and loaded with the antibacterial ciprofloxacin whereas an ion responsive hydrophilic layer has been produced by using an octyl derivative of gellan gum (GG-C8) and polyvinyl alcohol (PVA) and loaded with the growth factor FGF-2. This study investigated how the properties of this asymmetric membrane loaded with actives, were influenced by the ionotropic crosslinking of the hydrophilic layer. In particular, the treatment in DPBS and the crosslinking i…

HYALURONIC ACID-graft-ELASTIN BASED SCAFFOLDS FOR POTENTIAL TISSUE ENGINEERING APPLICATIONS

NEW SELF-ASSEMBLING POLYASPARTYLHYDRAZIDE COPOLYMER MICELLES FOR ANTICANCER DRUG DELIVERY.

A new amphiphilic copolymer have been synthesized starting from the hydrosoluble polyaspartylhydrazide (PAHy) polymer, by grafting both hydrophilic PEG(2000) chains and hydrophobic palmitic acid (C(16)) moieties on polymer backbone, and the structure of obtained PAHy-PEG(2000)-C(16) copolymer have been characterized by 2D (1)H/(13)C NMR experiments. PAHy-PEG(2000)-C(16) copolymer showed the ability of self-assembling in aqueous media giving a core-shell structure and resulted potentially useful for encapsulating and dissolving hydrophobic drug. The formation of micellar core-shell structure has been investigated by 2D (1)H NMR NOESY experiments. The presence of cross-peaks for protons of C(…

Hyaluronic acid based microparticles for applications in regenerative medicine

Perfluorocarbon functionalized hyaluronic acid derivatives as oxygenating systems for cell culture

A set of new hyaluronic acid (HA) derivatives was obtained by binding fluorinated oxadiazole (OXA) moieties to an amino derivative of the polysaccharide (HA-EDA). The obtained HA-EDA-OXA biomaterials are potentially able to improve oxygenation into a scaffold for tissue engineering purposes. The oxygen solubility in aqueous dispersions of the obtained derivatives showed that polymers were able to improve oxygen uptake and maintenance in the medium. The HA-EDA-OXA was employed to form a hydrogel in situ by reaction with a vinyl sulphone derivative of inulin, under physiological conditions. The influence of the presence of OXA moieties on the mechanical properties of the obtained hydrogels as…

Hyaluronic acid and alpha-elastin based hydrogel for three dimensional culture of vascular endothelial cells

Abstract The aim of this work was to demonstrate that employing a copolymer of hyaluronic acid and α-elastin (HA-EDA-g-α-elastin) is possible to produce a scaffold able to support the adhesion and growth of human vascular endothelial cells (HUVEC) thanks to its ability to incorporate and control the diffusion of vascular endothelial growth factor (VEGF). HA-EDA-g-α-elastin was crosslinked with low molecular weight hyaluronic acid (HALMW) to obtain a hydrogel that gives rise to the formation of three dimensional sponge after the freeze drying process. The physicochemical features the obtained material along with its ability to act as a support for the three dimensional culture of endothelial…

Hyaluronic acid and beta cyclodextrins films for the release of corneal epithelial cells and dexamethasone

In this work we prepared hydrogels based on hyaluronic acid and β-cyclodextrins to sustain the release of both corneal epithelial cells and dexamethasone. This steroid is administered as eye drops several times per day to reduce the risk of rejection in the post operative period after the cornea transplantation and cell release techniques. Hydrogels were produced by crosslinking an amino derivative of hyaluronic acid, with the divinyl sulfone derivative of β-cyclodextrins, this last employed as a crosslinker and solubilizing agent. Drug release studies revealed that dexamethasone containing samples are able to extend the release of this drug for at least five days. Biological studies, condu…

Photothermal nanofibrillar membrane based on hyaluronic acid and graphene oxide to treat Staphylococcus aureus and Pseudomonas aeruginosa infected wounds.

Here we reported the fabrication of an electrospun membrane based on a hyaluronic acid derivative (HA-EDA) to be used as a bandage for the potential treatment of chronic wounds. The membrane, loaded with graphene oxide (GO) and ciprofloxacin, showed photothermal properties and light-triggered drug release when irradiated with a near-infrared (NIR) laser beam. Free amino groups of HA-EDA derivative allowed autocrosslinking of the elec- trospun membrane; thus, a substantial enhancement in the hydrolytic resistance of the patch was obtained. In vitro antibacterial activity studies performed on Staphylococcus aureus and Pseudomonas aeruginosa revealed that such electrospun membranes, due to the…

Micelles of hyaluronic acid-hexadecylamine derivatives for ocular release of hydrophobic durgs

The topical route is the ideal way to release drugs to the eye. Unfortunately, the low ocular drug bioavailability associated with this route of administration, makes not very efficient the treatment of several ocular diseases. Nowadays, polymeric micelles occupy a significant role in the field of ocular drug delivery thanks to the advantages that they offer in comparison with the administration of drugs in the free form. Indeed, polymeric micelles are suitable for delivering hydrophobic drugs and they seem to be very promising in ocular drug delivery for their high kinetic and thermodynamic stability. Also, micellar systems are able to give a controlled drug release and to act as absorptio…

Microfibers of a Hyaluronic Acid Derivative to Mimic Blood Vessels

Injectable in situ forming microgels of hyaluronic acid-g-polylactic acid for methylprednisolone release

Abstract A hydrophobic derivative of hyaluronic acid (HA), obtained by grafting polylactic acid (PLA) to the polysaccharide, has been exploited to produce injectable in situ forming microgels. First of all, self assembling properties of HA-g-PLA copolymer have been evaluated by determining the critical aggregation concentration (CAC) value, then this copolymer has been dissolved in a mixture water/NMP 5:2 v/v with a concentration greater than CAC. When solutions at 1% or 2% w/v were injected into Dulbecco phosphate buffer solution (DPBS) pH 7.4, microgels promptly are formed. Their stability in DPBS pH 7.4 in the absence or in the presence of hyaluronidase and cell compatibility have been e…

Double-Network-Structured Graphene Oxide-Containing Nanogels as Photothermal Agents for the Treatment of Colorectal Cancer.

Here, we reported the production of hyaluronic acid/polyaspartamide-based double-network nanogels for the potential treatment of colorectal carcinoma. Graphene oxide, thanks to the huge aromatic surface area, allows to easily load high amount of irinotecan (33.0% w/w) and confers to the system hyperthermic properties when irradiated with a near-infrared (NIR) laser beam. We demonstrate that the release of antitumor drug is influenced both by the pH of the external medium and the NIR irradiation process. In vitro biological studies, conducted on human colon cancer cells (HCT 116), revealed that nanogels are uptaken by the cancer cells and, in the presence of the antitumor drug, can produce a…

PREPARAZIONE E CARATTERIZZAZIONE DI NUOVI SCAFFOLD BIOCOMPATIBILI PER APPLICAZIONI NELLA MEDICINA RIGENERATIVA

Microfibers and Nanoparticles with Controlled Dimensions of a Hyaluronic Acid Derivative

Microfluidics is defined as the technology that deals with the precise control and manipulation of small quantities of fluids constrained in micro-channels of small cross-sectional dimensions [1]. Microfluidics has recently emerged as a very promising route for the production of polymeric fibers at the micro and nanoscale, providing a fine control over fiber shape, size, chemical anisotropy and biological activity [2]. Furthermore, the ability to manipulate nanoliter volumes of liquid and to control mixing and reaction precisely, opens up the possibility of creating smart targeted drug delivery systems as nanoparticles, especially with uniform and narrow size distribution [3]. This work des…

Injectable in situ forming hydrogels based on natural and synthetic polymers for potential application in cartilage repair

In this work we prepared two new hyaluronic acid (HA) based in situ forming hydrogels for the potential treatment of articular cartilage damages. In particular the amino derivative of HA (HA-EDA) and its graft copolymer with α-elastin (HA-EDA-g-α-elastin) were crosslinked, in mild physiological conditions via Michael-type addition, with α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) derivatized with divinylsulfone (DV). The swelling and degradation profile of the obtained hydrogels as well as the metabolic activity of incorporated bovine articular chondrocytes were investigated. Histological analysis and scanning electron microscopy (SEM) were performed to analyze the morphology of cells …

Chemical stiffening of constructs between polymeric microparticles based on a hyaluronic acid derivative and mesenchymal stem cells: rheological and in vitro viability studies

Our research group has recently developed microparticles of a hyaluronic acid derivative used for bottom-up growth of microparticles/human mesenchymal stem cells (hMSCs). In this work, we investigated a strategy to increase the stiffening of aggregated constructs between microparticles and hMSCs. In particular, we applied a Michael-type crosslinking procedure between microparticles to allow a chemically driven and cell-compatible stiffening of constructs. Two batches of microparticles were functionalized with thiol and maleimide groups, respectively, and were then mixed to allow chemical crosslinking. The adhesion of hMSCs was controlled through addition of the adhesive peptide cyclo(-Arg-G…

Biocompatible Hydrogels Based on Hyaluronic Acid Cross-Linked with a Polyaspartamide Derivative as Delivery Systems for Epithelial Limbal Cells

A Fibrillar Biodegradable Scaffold for Blood Vessels Tissue Engineering

In recent years there has been a growing interest for the development of tubular scaffolds employed to assist the replacement of small blood vessels. Materials designed for this purpose need to be biodegradable, have good mechanical properties and improve cell adhesion, proliferation and differentiation. To obtain biomaterials with these properties, electrospinning seems to be one of the most useful technique. Several biodegradable synthetic polymers or constituents of the extracellular matrix (ECM) have been electrospun showing optimal mechanical properties and biodegradability. However, such polymers are lacking in versatile chemical structure affordable to immobilize growth factors or ch…

NEW PEGYLATED POLYHYDROXYETHYLASPARTAMIDE-SPERMINE COPOLYMER AS GENE DELIVERY SYSTEM

Heparin functionalized polyaspartamide/polyester scaffold for potential blood vessel regeneration

An interesting issue in tissue engineering is the development of a biodegradable vascular graft able to substitute a blood vessel and to allow its complete regeneration. Here, we report a new scaffold potentially useful as a synthetic vascular graft, produced through the electrospinning of α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-D,L-aspartamide-graft-polylactic acid (PHEA-EDA-g-PLA) in the presence of polycaprolactone (PCL). The scaffold degradation profile has been evaluated as well as the possibility to bind heparin to electrospun fibers, being it a known anticoagulant molecule able to bind growth factors. In vitro cell compatibility has been investigated using human vascular e…

Correlating Rheological Properties of a Gellan Gum-Based Bioink: A Study of the Impact of Cell Density.

Here, for the production of a bioink-based gellan gum, an amino derivative of this polysaccharide was mixed with a mono-functionalized aldehyde polyethyleneglycol in order to improve viscoelastic macroscopic properties and the potential processability by means of bioprinting techniques as confirmed by the printing tests. The dynamic Schiff base linkage between amino and aldehyde groups temporally modulates the rheological properties and allows a reduction of the applied pressure during extrusion followed by the recovery of gellan gum strength. Rheological properties, often related to printing resolution, were extensively investigated confirming pseudoplastic behavior and thermotropic and io…

Multifibrillar bundles of a self-assembling hyaluronic acid derivative obtained through a microfluidic technique for aortic smooth muscle cell orientation and differentiation

A hyaluronic acid derivative that is able to physically crosslink in a saline aqueous environment was employed for the production of fibers with a mean diameter of 50 μm using a microfluidic technique. The microfibers were collected in a tailored rotating collector and assembled to form multifibrillar bundles. The orientation of the microfibers on the collected bundles was evaluated by microCT analysis. The bundles were biofunctionalized by physical addition of fibronectin or chemical tethering of a cyRGDC peptide to achieve control of Aortic Smooth Muscle Cell (AoSMC) attachment, elongation and alignment. The mechanical performances of these bundles were evaluated by elongation tests, rela…

Graphene oxide containing hyaluronic acid based nanogels for the potential treatment of colorectal cancer

Here, we reported the production of graphene oxide (GO) containing nanogels produced by a top-down procedure employing as a starting biomaterial an amino derivative of hyaluronic acid named HA-EDA. This derivative was reacted, in the presence of single layer GO, with α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide-((2-aminoethyl)-carbamate)-divinyl sulfone (PHEA-DVS) employed as a macromolecular crosslinking agent. The so obtained hydrogel was homogenized by ultra-turrax and high pressure homogenizer and nanogels with Z-average of 390 nm and PDI of 0.22 were obtained. These nanogels were employed to incorporate Irinotecan (IT), an antitumor drug used in the treatment of colorectal carcinoma. It …

Electrospun PHEA-PLA/PCL Scaffold for Vascular Regeneration: A Preliminary in Vivo Evaluation

Abstract Background There is increasing interest in the development of vessel substitutes, and many studies are currently focusing on the development of biodegradable scaffolds capable of fostering vascular regeneration. We tested a new biocompatible and biodegradable material with mechanical properties similar to those of blood vessels. Methods The material used comprises a mixture of α,β-poly(N-2-hydroxyethyl)- d,l -aspartamide (PHEA) and polylactic acid (PLA), combined with polycaprolactone (PCL) by means of electrospinning technique. Low-molecular-weight heparin was also linked to the copolymer. A tubular PHEA-PLA/PCL sample was used to create an arteriovenous fistula in a pig model wit…

Hyaluronic acid, elastin and heparin containing scaffolds for the treatment of skin chronic wounds

PRODUCTION OF MICELLES FROM HYALURONIC ACID AMPHIPHILIC DERIVATIVES FOR TARGETED RELEASE OF DOXORUBICIN

Medicated hydrogels of hyaluronic acid derivatives for use in orthopedic field

Heparin functionalized polyaspartamide/polyester scaffold for potential blood vessel regeneration

A hyaluronic acid/cyclodextrin based injectable hydrogel for local doxorubicin delivery to solid tumors

Localized delivery of anticancer drugs is often the most useful therapeutic approach for the treatment of solid tumors. The use of injectable polymeric systems that maximize drug concentration in the proximal area of the tumor represents an extremely advantageous therapeutic strategy. Here, the development of an injectable in situ forming hydrogel was accomplished by exploiting the azo-type Michael reaction between an amine derivative of hyaluronic and vinylsulfone functionalized -cyclodextrins complexing doxorubicin. This injectable system can be easily prepared and administered with timelines compatible with normal operating room procedures, as demonstrated by rheological tests. In vitro…

Polyaspartamide-graft- Polymethacrylate Nanoparticles for Doxorubicin Delivery

A new PHEA-IB-PMANa + copolymer has been synthesized and its pH-induced self-assembly has been investigated in an aqueous medium. PHEA-IB-PMANa + formed nanoparticles with diameters from 25 to 50 nm upon protonation of the carboxylic acid moieties dislocated along the grafted polymethacrylate sodium salt side chains. The physico-chemical characterization of the nanoparticles was performed using light scattering, zeta-potential measurements, SEM, and AFM. Doxorubicin-loaded nanoparticles were prepared and drug release profiles were evaluated under conditions mimicking physiological media. A biological characterization was carried out by testing the cytotoxicity on Caco-2 cells, and cellular …

Spray dried hyaluronic acid microparticles for adhesion controlled aggregation and potential stimulation of stem cells

Spray-dried microparticles of a derivative of hyaluronic acid (HA) have been engineered to obtain a controlled aggregation with Human Mesenchymal Stem Cells (hMSCs) into 3D constructs. We demonstrated the utility of chemical functionalization of a native constituent of the extracellular matrix to improve processing performances and to control on stem cell adhesion and differentiation. Native hyaluronic acid (HA), cell adhesive peptides (RGD), transforming growth factor β3, dexamethasone are biological agents potentially suitable for chondrogenic stimulation of hMSCS. However unmodified HA suffers of drawbacks in terms of stability and versatility of processing. Functionalization strategies…

New hyaluronic acid based brush copolymers synthesized by atom transfer radical polymerization.

Abstract In this work, an efficient method for the synthesis of hyaluronic acid based brush copolymers using atom transfer radical polymerization (ATRP) has been reported. At first, two different hyaluronic acid (HA) based macroinitiators have been prepared and then they have been used for the polymerization via ATRP of hydrophilic or hydrophobic molecules carrying vinyl portions. In particular, by linking 2-bromo-2-methylpropionic acid (BMP) to the primary hydroxyl groups of tetrabutyl ammonium salt of HA (HA–TBA) or to amino groups of the ethylenediamino derivative of HA–TBA (HA–TBA–EDA), two macroinitiators (HA–TBA–BMP and HA–TBA–EDA–BMP) have been obtained. Then they have been used for …

Development of an lbuprofen-Releasing Biodegradable PLA/PGA Electrospun Scaffold for Tissue Regeneration

Our aim was to develop a biodegradable fibrous dressing to act as a tissue guide for in situ wound repair while releasing Ibuprofen to reduce inflammation in wounds and reduce pain for patients on dressing changes. Dissolving the acid form of Ibuprofen (from 1% to 10% by weight) in the same solvent as 75% polylactide, 25% polyglycolide (PLGA) polymers gave uniformly loaded electrospun fibers which gave rapid release of drug within the first 8 h and then slower release over several days. Scaffolds with 10% Ibuprofen degraded within 6 days. The Ibuprofen released from these scaffolds significantly reduced the response of fibroblasts to major pro-inflammatory stimulators. Fibroblast attachment…

Chemical hydrogels based on a hyaluronic acid-graft-α-elastin derivative as potential scaffolds for tissue engineering

In this work hyaluronic acid (HA) functionalized with ethylenediamine (EDA) has been employed to graft α-elastin. In particular a HA-EDA derivative bearing 50 mol% of pendant amino groups has been successfully employed to produce the copolymer HA-EDA-g-α-elastin containing 32% w/w of protein. After grafting with α-elastin, remaining free amino groups reacted with ethylene glycol diglycidyl ether (EGDGE) for producing chemical hydrogels, proposed as scaffolds for tissue engineering. Swelling degree, resistance to chemical and enzymatic hydrolysis, as well as preliminary biological properties of HA-EDA-g-α-elastin/EGDGE scaffold have been evaluated and compared with a HA-EDA/EGDGE scaffold. T…

MODIFIED PEPTIDE RELEASE FROM NEW IN SITU GEL FORMING COPOLYMERS BASED ON POLYLACTIDE AND POLYASPARTAMIDE

Inulin Derivatives Obtained Via Enhanced Microwave Synthesis for Nucleic Acid Based Drug Delivery

A new class of therapeutic agents with a high potential for the treatment of different socially relevant human diseases is represented by Nucleic Acid Based Drugs (NABD), including small interfering RNAs (siRNA), decoy oligodeoxynucleotides (decoy ODN) and antisense oligonucleotides (ASOs). Although NABD can be engineered to be specifically directed against virtually any target, their susceptibility to nuclease degradation and the difficulty of delivery into target tissues severely limit their use in clinical practice and require the development of an appropriate nanostructured delivery system. For delivery of NABD, Inulin (Inu), a natural, water soluble and biocompatible polysaccharide, wa…

Polyaspartamide based hydrogel with cell recruitment properties for the local administration of hydrophobic anticancer drugs

Abstract By exploiting the chemical versatility and the high water dispersibility of α,β-poly(N-2-hydroxyethyl)D,L-aspartamide, in this work, two different polymer derivatives were synthesized for the first time. Obtained macromolecules were characterized and used to produce hydrogels exploitable for the local release of hydrophobic anticancer drugs. The first derivative, bearing pendant β-cyclodextrins, was employed to solubilize tamoxifen, chosen as a model drug, and to produce a water soluble supramolecular complex, as evidenced through tamoxifen phase solubility studies. The second derivative, bearing pendant Cyclo(Arginine-Glyicine-Asparagine-D-Phenilyalanine-Cysteine) peptide moieties…

Physicochemical and Rheological Characterization of Different Low Molecular Weight Gellan Gum Products and Derived Ionotropic Crosslinked Hydrogels

A series of four different low molecular weight gellan gum products was obtained by alkaline hydrolysis with the aim to investigate the impact of the molecular weight on the rheological properties of the polysaccharide aqueous dispersions and on the physicochemical characteristics of derived ionotropic crosslinked hydrogels. In particular, thermo-rheological analysis was conducted on aqueous dispersions to study the influence of molecular weight on the thermogelation properties typical of the native polysaccharide while strain sweep experiments were conducted to establish if aqueous dispersion shows a viscoelastic behavior. The effect of different Ca2+ on the rheological properties of hydro…

A Novel Peptide with Antifungal Activity from Red Swamp Crayfish Procambarus clarkii

The defense system of freshwater crayfish Procambarus clarkii as a diversified source of bioactive molecules with antimicrobial properties was studied. Antimicrobial activity of two polypeptide-enriched extracts obtained from hemocytes and hemolymph of P. clarkii were assessed against Gram positive (Staphylococcus aureus, Enterococcus faecalis) and Gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria and toward the yeast Candida albicans. The two peptide fractions showed interesting MIC values (ranging from 11 to 700 μg/mL) against all tested pathogens. Polypeptide-enriched extracts were further investigated using a high-resolution mass spectrometry and database search and 14 n…

Micelles of hyaluronic acid-hexadecylamine derivatives for ocular release of hydrophobic drugs

Dexamethasone Dipropionate Loaded Nanoparticles Of -Elastin-G-Plga For Potential Treatment Of Restenosis

Synthesis and evaluation of thermo-rheological behaviour and ionotropic crosslinking of new gellan gum-alkyl derivatives.

Abstract This paper reports the synthesis and the physicochemical characterization of two series of gellan gum (GG) derivatives functionalized with alkyl chains with different number of carbon, from 8 to 18. In particular, low molecular weight gellan gum samples with 52.6 or 96.7 kDa, respectively, were functionalized with octylamine (C8), dodecylamine (C12) and octadecylamine (C18) by using bis(4-nitrophenyl) carbonate (4-NPBC) as a coupling agent. Thermo-rheological and ionotropic crosslinking properties of these gellan gum-alkyl derivatives were evaluated and related to the degree of derivatization in alkyl chains. Results suggested as length and degree of derivatization differently infl…

In situ forming hydrogels of hyaluronic acid and inulin derivatives for cartilage regeneration.

An in situ forming hydrogel obtained by crosslinking of amino functionalized hyaluronic acid derivatives with divinylsulfone functionalized inulin (INU-DV) has been here designed and characterized. In particular two hyaluronic acid derivatives bearing respectively a pendant ethylenediamino (EDA) portion (HA-EDA) and both EDA and octadecyl pendant groups (HA-EDA-C18) were crosslinked through an azo-Michael reaction with INU-DV. Gelation time and consumption of DV portions have been evaluated on hydrogel obtained using HA-EDA and HA-EDA-C18 derivatives with a concentration of 3% w/v and a ratio 80/20 w/w respect to the crosslinker INU-DV. The presence of pendant C18 chains improves mechanical…

Mechanical Characterization of Polysaccharide/polyaminoacid Hydrogels as Potential Scaffolds for Tissue Regeneration

The mechanical properties of hydrogel scaffolds based on hyaluronic acid (HA) that were chemically crosslinked with α,β-poly(N-2-hydroxyethyl)(2-aminoethylcarbamate)-D,L-aspartamide (PHEA-EDA) were investigated. Variation of these properties as a function of three different PHEA-EDA amounts used to crosslink HA has been related to the reaction efficiency evaluated using a colorimetric assay. Moreover, the amount of unreacted amino groups that was still present in the hydrogels was related to the attachment behavior of human dermal fibroblasts to the hydrogel surface. The mechanical data and biological results suggest the suitability of the investigated hydrogels as scaffolds for the regener…

Developing Antibiofilm Fibrillar Scaffold with Intrinsic Capacity to Produce Silver Nanoparticles

The development of biomedical systems with antimicrobial and antibiofilm properties is a difficult medical task for preventing bacterial adhesion and growth on implanted devices. In this work, a fibrillar scaffold was produced by electrospinning a polymeric organic dispersion of polylactic acid (PLA) and poly(α,β-(N-(3,4-dihydroxyphenethyl)-L-aspartamide-co-α,β-N-(2-hydroxyethyl)-L-aspartamide) (PDAEA). The pendant catechol groups of PDAEA were used to reduce silver ions in situ and produce silver nanoparticles onto the surface of the electrospun fibers through a simple and reproducible procedure. The morphological and physicochemical characterization of the obtained s…

Using Polymeric Scaffolds for Vascular Tissue Engineering

With the high occurrence of cardiovascular disease and increasing numbers of patients requiring vascular access, there is a significant need for small-diameter (<6 mm inner diameter) vascular graft that can provide long-term patency. Despite the technological improvements, restenosis and graft thrombosis continue to hamper the success of the implants. Vascular tissue engineering is a new field that has undergone enormous growth over the last decade and has proposed valid solutions for blood vessels repair. The goal of vascular tissue engineering is to produce neovessels and neoorgan tissue from autologous cells using a biodegradable polymer as a scaffold. The most important advantage of …

Medicated hydrogels of hyaluronic acid derivatives for use in orthopedic field.

Physical hydrogels have been obtained from hyaluronic acid derivatized with polylactic acid in the presence or in the absence of polyethylene glycol chains. They have been extemporarily loaded with antibacterial agents, such as vancomycin and tobramycin. These medicated hydrogels have been used to coat titanium disks (chosen as simple model of orthopedic prosthesis) and in vitro studies in simulated physiological fluid have been performed as a function of time and for different drug loading and polymer concentration values. Sterilization process performed on the hydrogels does not change their rheological behavior and release properties as well as the chemical structure of starting copolyme…

Chemical stiffening of constructs between polymeric microparticles based on a hyaluronic acid derivative and mesenchymal stem cells: rheological and in vitro viability studies

Hyaluronan alkyl derivatives-based electrospun membranes for potential guided bone regeneration: Fabrication, characterization and in vitro osteoinductive properties

Item does not contain fulltext The aim of the work was to determine the effects of the chemical functionalization of hyaluronic acid (HA) with pendant aliphatic tails at different lengths and free amino groups in terms of chemical reactivity, degradation rate, drug-eluting features, and surface properties when processed as electrospun membranes (EM) evaluating the osteoinductive potential for a possible application as guided bone regeneration (GBR). To this end, a series of HA derivatives with different aliphatic tails (DD-Cx mol% ≈ 12.0 mol%) and decreasing derivatization of free amino groups (DD(EDA) mol% from 70.0 to 30.0 mol%) were first synthesized, namely Hn. Then dexamethasone-loaded…

Polymeric drug delivery micelle-like nanocarriers for pulmonary administration of beclomethasone dipropionate

In this paper, the potential of novel polymeric micelles as drug delivery systems for Beclomethasone Dipropionate (BDP) administration into the lung is investigated. These nanostructures are obtained starting from α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA), which was subsequently functionalized with O-(2-aminoethyl)-O’-methylpolyethylenglycole (PEG2000), ethylenediamine (EDA) and lipoic acid (LA), obtaining PHEA-PEG2000-EDA-LA graft copolymer. Empty and drug-loaded micelles possess adequate chemical-physical characteristics for pulmonary administration such as spherical shape, slightly positive surface charge and mean size of about 200 nm. Besides, BDP-loaded micelles, obtained …

Construction and evaluation of sponge scaffolds from hyaluronic acid derivatives for potential cartilage regeneration

A two or one pot synthesis has been used for the reaction of hyaluronic acid (HA) with octadecylamine (C-18) and hydrazine (Hy). In both cases, the chemical derivatization involved primary hydroxyl groups of hyaluronic acid and not its carboxyl groups, whose presence is important for receptor interaction. In this way, Hy-HA-C-18 derivatives have been obtained with appropriate hydrophobic and hydrophilic character. Their ability to form homogeneous physical hydrogels has been evaluated as well as the possibility to obtain porous sponges through salt leaching technology. Sponges showing the highest porosity, potentially compatible with cell entrapment, have been characterized with regard to t…

Sistemi sopramolecolari cationici innovativi per la veicolazione polmonare dei bioattivi.

ATRP AS AN EFFICIENT METHOD TO PRODUCE BRUSH COPOLYMERS OF HYALURONIC ACID

PREPARATION AND CHARACTERIZATION OF GALACTOSILATED NANODEVICES CONTAINING A RIBAVIRIN PRODRUG FOR LIVER TARGETING.

Microfibers obtained by electrospinning of alpha, beta poly(N-2-hydroxyethyl)-DL-aspartamide-g-polylactic acid for potential use in tissue reconstruction

Electrospinning of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide-graft-polylactic acid to produce a fibrillar scaffold

Abstract α,β-Poly( N -2-hydroxyethyl)- dl -aspartamide grafted with polylactic acid (PHEA- g -PLA) is a biocompatible and biodegradable amphiphilic copolymer that has been already employed to prepare a drug delivery system. In this study we have prepared for the first time a fibrillar scaffold from PHEA- g -PLA by the electrospinning of a solution of this copolymer in a mixture of N , N -dimethyl formamide (DMF) and acetone (80:20 vol/vol). The average diameter and the morphology of electrospun fibers were detected by scanning electron microscopy. Chemical degradation studies in phosphate buffer solution pH 7.4 have been performed until 15 days in order to obtain a preliminary information a…

ANTICANCER RELEASING FILMS AND POROUS SCAFFOLDS BASED ON PHYSICALLY ASSEMBLED HYALURONIC ACID DERIVATIVES

Microfluidic Fabrication of Physically Assembled Nanogels and Micrometric Fibers by Using a Hyaluronic Acid Derivative

The employ of a hyaluronic acid (HA) derivative, bearing octadecyl (C18) and ethylenediamine (EDA) groups, for microfluidic fabrication of nanogels and microfibers is reported in this study. Two HA-EDA-C18 derivatives (125 and 320 kDa) having ionic strength sensitive properties are synthesized and characterized. The control of the rheological properties of HA-EDA-C18 aqueous dispersions by formation of inclusion complexes with hydroxypropyl-β-cyclodextrins (HPCD) is described. Reversibility of C18/HPCD complexation and physical crosslinking is detected in media with different ionic strength through oscillation frequency tests. HA-EDA-C18 125 kDa is employed for nanogel fabrication. Control …

Inulin-Based Hydrogel for Oral Delivery of Flutamide: Preparation, Characterization, and in vivo Release Studies

The ability of a hydrogel obtained by crosslinking INUDV and PEGBa to facilitate sustained release of flutamide is examined. The hydrogel is prepared in pH 7.4 PBS and no toxic solvents or catalysts are used. It is recovered in microparticulate form and its size distribution is determined. Mucoadhesive properties are evaluated in vitro by reproducing gastrointestinal conditions. Flutamide is loaded into the hydrogel using a post-fabrication encapsulation procedure that allows a drug loading comparable to that of market tablets. Drug-loaded microparticles are orally administered to cross-bred dogs and the in vivo study demonstrates their ability to prolong the half-life of the principal acti…

Polyaspartamide-polylactide electrospun scaffolds for potential topical release of Ibuprofen.

In this work, the production and characterization of electrospun scaffolds of the copolymer α,β-poly(N-2-hydroxyethyl)-DL-aspartamide-graft-polylactic acid (PHEA-g-PLA), proposed for a potential topical release of Ibuprofen (IBU), are reported. The drug has been chemically linked to PHEA-g-PLA and/or physically mixed to the copolymer before electrospinning. Degradation studies have been performed as a function of time in Dulbecco phosphate buffer solution pH 7.4, for both unloaded and drug-loaded scaffolds. By using an appropriate ratio between drug physically blended to the copolymer and drug-copolymer conjugate, a useful control of its release can be obtained. MTS assay on human dermal fi…

A hyaluronic acid derivative as a coating film for an electrospun cell releasing system in the treatment of corneal wounds

The transparency of the cornea is maintained by the stem cells of the corneal epithelium in the limbal region; damage to the limbus may cause partial or total limbal stem cell deficiency that, may lead to blindness. The transplantation of cells is crucial to regenerate the damaged areas. The techniques currently employed consist in cadaveric corneal transplantation or in the use of amniotic membrane as a carrier for delivering cultured limbal stem cells to the cornea. Both these approaches show severe drawbacks such as the potential reject of the transplanted cornea and the risk of viral disease transmissions. Here we report the production of an electrospun device that could be exploited as…

NEW IN SITU FORMING HYALURONIC ACID SCAFFOLDS WITH A FIBRILLAR STRUCTURE

FIBRILLAR SCAFFOLD BASED ON ELECTROSPUN alpha,beta-POLY(N-2-HYDROXYETHYL)-DL-ASPARTAMIDE-GRAFT-POLYLACTIC ACID COPOLYMER.

Polyaspartamide-graft-polymethacrylate nanoparticles for doxorubicin delivery

New hyaluronic acid based brush copolymers synthesized by atom transfer radical polymerization

Polyaspartamide-polylactide electrospun scaffolds for potential topical release of ibuprofen

Fabrication of silver nanoparticles by a diethylene triamine-hyaluronic acid derivative and use as antibacterial coating

In this work a synthetic protocol for the functionalization of hyaluronic acid with diethylenetriamine (DETA) was standardized. HA-DETA derivatives were characterized by NMR and proton carbon correlation analysis HSQC and HMBC to confirm chemical structure. A selected derivative was used to set up a green fabrication procedure for HA-DETA capped silver nanoparticles with the aim to achieve a polymeric based coating with potential application in the treatment of medical devices associated infections. Data from UV-visible spectroscopy, electron scanning and transmission microscope (STEM), photoelectric spectroscopy (XPS) and rheological characterization were combined to characterize the HA-DE…

An allergen-polymeric nanoaggregate as a new tool for allergy vaccination.

Parietaria pollen is one of the major causes of allergic reaction in southern Europe, affecting about 30% of all allergic patients in this area. Specifi immunotherapy is the only treatment able to modify the natural outcome of the disease by restoring a normal immunity against allergens. The preparation of allergen-solid lipid nanoparticles as delivery vehicles for therapeutic proteins, P. judaica major allergen Par j 2, was investigated. The Par j 2 allergen was expressed in a large amount in Escherichia coli and purifid to homogeneity. Its immunological properties were studied by western blotting and enzyme-linked immunosorbent assay inhibition. Solid lipid nanoparticles were obtained by …

Interpenetrated 3D porous scaffolds of silk fibroin with an amino and octadecyl functionalized hyaluronic acid

An ethylenediamine (EDA) and octadecylamine (-C18) hyaluronic acid (HA) derivative, named HA-EDA-C18, has been used for the production of interpenetrated composite biomaterials with silk fibroin. The peculiar ionic strength sensibility of this HA derivative allows the production of porous matrices without the need for chemical crosslinking. Scaffolds have been produced through a salt leaching procedure by exploiting the properties of silk fibroin and HA-EDA-C18 to physically crosslink when forced through a syringe loaded with NaCl. The porosity of the sponges, comprised between 70-80%, was dependent on the amount of each polymer and NaCl size distribution. Moreover, through FT-IR analysis, …

New gellan gum-graft-poly(D,L-lactide-co-glycolide) copolymers as promising bioinks: Synthesis and characterization

This research focused on the aim of tackling the urgent demand of printable biomaterials, hence we synthetized and characterized three gellan gum-graft-poly(d,l-lactide-co-glycolide) copolymers (GGm-PLGA a, b and c) which differed in the graft substitution degree. We investigated the effect of the polyester chain grafted onto hydrophilic backbone of gellan gum in terms of physicochemical properties and the ability of the system to print 3D cell laden constructs. In particular, we evaluated thermo-rheological, ionotropic crosslinking, shear thinning, swelling and stability properties of these copolymers and their derived biomaterials and findings related to the degree of functionalization. M…

Inulin Derivatives Obtained <i>Via</i> Enhanced Microwave Synthesis for Nucleic Acid Based Drug Delivery

A new class of therapeutic agents with a high potential for the treatment of different socially relevant human diseases is represented by Nucleic Acid Based Drugs (NABD), including small interfering RNAs (siRNA), decoy oligodeoxynucleotides (decoy ODN) and antisense oligonucleotides (ASOs). Although NABD can be engineered to be specifically directed against virtually any target, their susceptibility to nuclease degradation and the difficulty of delivery into target tissues severely limit their use in clinical practice and require the development of an appropriate nanostructured delivery system. For delivery of NABD, Inulin (Inu), a natural, water soluble and biocompatible polysaccharide, wa…

Production of a Double-Layer Scaffold for the “On-Demand” Release of Fibroblast-like Limbal Stem Cells

The production and characterization of a double layer scaffold, to be used as a system for the “on demand” release of corneal limbal stem cells are here reported. The devices used in the clinics and proposed so far in the scientific literature, for the release of corneal stem cells in the treatment of limbal stem cell deficiency, cannot control the in vivo space-time release of cells since the biomaterial of which they are composed is devoid of stimuli responsiveness features. Our approach was to produce a scaffold composed of two different polymeric layers that give the device the appropriate mechanical properties to be placed on the ocular surface and the possibility of releasing the stem…

Composite Hydrogels of Alkyl Functionalized Gellan Gum Derivative and Hydroxyapatite/Tricalcium Phosphate Nanoparticles as Injectable Scaffolds for bone Regeneration

An alkyl functionalized gellan gum derivative was here used to produce hydrogels containing hydroxyapatite and tricalcium phosphate nanoparticles as injectable nanostructured scaffolds for bone regeneration. The amphiphilic nature of the polysaccharide derivative along with its thermotropic behavior and ionotropic crosslinking features made possible to produce injectable bone mimetic scaffolds that can be used to release viable cells and osteoinductive biomolecules. The influence of different nanoparticles concentration on the rheological and physicochemical properties of the injectable systems was studied. We found that the presence of inorganic nanoparticles reinforces the three-dimension…

Hyaluronic Acid-g-Copolymers: Synthesis, Properties, and Applications

Electrospun Polyhydroxyethyl-Aspartamide-Polylactic Acid Scaffold for Biliary Duct Repair: A Preliminary In Vivo Evaluation

Abstract Tissue engineering has emerged as a new approach with the potential to overcome the limitations of traditional therapies. The objective of this study was to test whether our polymeric scaffold is able to resist the corrosive action of bile and to support a cell's infiltration and neoangiogenesis with the aim of using it as a biodegradable tissue substitute for serious bile duct injuries. In particular, a resorbable electrospun polyhydroxyethyl-aspartamide–polylactic acid (90 mol% PHEA, 10 mol% PLA)/polycaprolactone (50:50 w/w) plate scaffold was implanted into rabbit gallbladder to assess the in vivo effects of the lytic action of the bile on the scaffold structure and then as a tu…

A methacrylic hyaluronic acid derivative for potential application in oral treatment of celiac disease.

Objective: Aim of this work was the synthesis of a methacrylic hyaluronic acid (HA) derivative and the production, via photocrosslinking, of related hydrogels loaded with an endopeptidase intended for a potential oral treatment of celiac disease. Methods: The methacrylic derivative of HA was prepared through a one-pot procedure involving the reaction with ethylenediamine (EDA) and methacrylic anhydride (MA). The obtained derivative, named HA-EDA-MA, was used to prepare photocrosslinked hydrogels loaded with a prolyl endopeptidase derived from Flavobacterium meningosepticum (PEP FM) able to detoxify gliadin. Obtained hydrogels were recovered as gels or freeze-dried powders. Results: Hydrogel…

MICELLES OF AMPHYPHLIC HYALURONIC ACID DERIVATIVES FOR TARGETED DELIVERY OF DOXORUBICIN

A facile way to build up branched high functional polyaminoacids with tunable physicochemical and biological properties

Abstract Here, for the first time, branched polyaminoacids bearing α-amino acids as side functions, namely PAA-co-AA and PGA-co-AA, are prepared by heterophase ring opening of polysuccinimide (PSI) with l -arginine or glycine in aqueous environment and at controlled pH. The modulation of the pH of the reaction leads to high-molecular-weight copolymers with tunable functionalization and, as consequence, with tailor-made physicochemical properties. Furthermore, a branched polyaminoacid carrying a preformed bioactive peptide ( l -trileucine) and l -arginine as side pendants, named PATA-co-AA, was synthesized via a similar pathway thus leading to complex biomimetic materials potentially exploit…

Inulin vinyl sulfone derivative cross-linked with bis-amino PEG: new materials for biomedical applications

In this work new hydrogels based on biocompatible polymers such as inulin (INU) and O,O'-bis(2-aminoethyl)polyethyleneglycol (PEGBa) have been prepared and charaterized. In particular, INU has been derivatized with divinyl sulfone (DV) thus obtaining the INUDV derivative, a copolymer bearing double bonds highly reactive towards the conjugate addition by nucleophilic molecules. INUDV has been characterized by FT-IR, 1 H-NMR and SEC analyses that have confirmed the success of the derivatization reaction. With the aim to obtain novel hydrogel systems, INUDV derivative has been cross-linked with PEGBa in phosphate buffer solution pH 7.4. The reaction has been carried out for 4 h at room tempera…

BIODEGRADABLE POLYASPARTAMIDE-GRAFT-POLYESTER COPOLYMER FOR VASCULAR REGENERATION

HYDROGELS OF HYALURONIC ACID-GRAFT-alfa-ELASTIN AS EXTRACELLULAR MATRIX SUBSTITUTES

Par j 1/Par j 2-nanoaggregati: un nuovo strumento per la terapia antiallergica

MATRICES OF A HYDROPHOBICALLY FUNCTIONALIZED HYALURONIC ACID DERIVATIVE FOR THE LOCOREGIONAL TUMOUR TREATMENT

A hyaluronic acid (HA) derivative bearing octadecylamine and acylhydrazine functionalities has been here employed for the production of a paclitaxel delivering matrix for locoregional chemotherapy. Through a strategy consisting in a powder compression and a plasticization with a mixture water/ethanol, a physically assembled biomaterial, stable in solutions with physiologic ionic strengths, has been produced. Two different drug loading strategies have been adopted, by using paclitaxel as chemotherapic agent, and obtained samples have been assayed in terms of release in enhanced solubility conditions and in vitro and in vivo tumoural cytotoxicity. In particular sample with the best releasing …

A self-sterilizing fluorescent Nanocomposite as versatile material with broad-spectrum Antibiofilm features

Abstract Hematogenous spread of infections from colonized central intravenous catheters or central lines is a long-recognized problem with infection rates of 2 and 6.8 per 1000 days, respectively. Besides, removal of severe microbial colonization of implanted biomaterials is still a challenge and usually requires invasive operations. Hence, on demand self-sterilizing materials are required to avoid explant of colonized biomaterials and improve patient compliance. Moreover, photoluminescence is needed to make trackable biomaterials, which can be easily monitored upon implanting them in the body. Here, we propose the incorporation of near infrared (NIR) sensitive red-emitting carbon nanodot (…

SELF-ASSEMBLED AMPHIPHILIC HYALURONIC ACID GRAFT COPOLYMERS FOR TARGETED RELEASE OF ANTITUMORAL DRUG

Polymeric micelles obtained by self-assembling of amphiphilic hyaluronic acid (HA) graft copolymers have been prepared and characterized. In particular, hyaluronic acid (HA) has been grafted to polylactic acid (PLA) and polyethylenglycol chains (PEG), then the copolymers able to form micelles in aqueous medium have been chosen to entrap the antitumoral drug Doxorubicin. The critical aggregation concentration of HA-g-PLA or HA-g-PLA-g-PEG micelles has been determined by using pyrene as a fluorescent probe, whereas their shape and size have been evaluated by light scattering measurements, scanning and transmission electron microscopies. The selective cytotoxicity of drug loaded micelles towar…

Hyaluronic Acid Derivative with Improved Versatility for Processing and Biological Functionalization

A hydrophobic/amino functionalized derivative of hyaluronic acid (HA-EDA-C18 ) has been processed by salt leaching technique as porous scaffold without need of chemical crosslinking. Aim of this work is to demonstrate the improved versatility of HA-EDA-C18 in terms of processing and biological functionalization. In particular, the chemical procedure to tether thiol bearing RGD peptide has been described. Moreover, the possibility to load and to control the release of slightly water soluble effectors has been demonstrated by using dexamethasone. First, the swelling and degradation profiles of the scaffolds have been investigated, then the evaluation of metabolic activity of bovine chondrocyt…

HYALURONIC ACID BASED-MICELLES FOR OFF-LABEL USE OF IMATINIB IN RETINOPATHIES TREATMENT

The aim of this work was to obtain polymeric micelles able to cross corneal barrier and to improve the permeation of imatinib free base. Micelles were prepared by using hyaluronic acid (HA) derivatives containing ethylenediamine (EDA), chains of hexadecyl (C16), polyethylene glycol (PEG) and/or L-carnitine (CRN). The resulting samples, named as HA-EDA-C16, HA-EDA-C16-PEG and HA-EDA-C16-CRN micelles, were designed to allow a non-invasive way of administration, i.e. topical ocular instillation. These nanocarriers showed an optimal particle size in aqueous media and mucoadhesive properties. Imatinib-loaded micelles were able to interact with corneal barrier and to promote imatinib transcorneal…

SELF ASSEMBLED AND CROSSLINKED FIBRILLAR SCAFFOLDS FOR CARTILAGE REGENERATION.

Development of stimulus-sensitive electrospun membranes based on novel biodegradable segmented polyurethane as triggered delivery system for doxorubicin

In this work, redox-sensitive polyurethane urea (PUU) based electrospun membranes have been exploited to chemically tether a pH-sensitive doxorubicin derivative achieved by linking a lipoyl hydrazide to the drug via a hydrazone linkage. First, the lipoyl-hydrazone-doxorubicin derivative labelled as LA-Hy-Doxo has been syn- thesized and characterized. Then, the molecule has been tethered, via a thiol-disulfide exchange reaction, to the redox-sensitive PUU (PolyCEGS) electrospun membrane. The redox-sensitive PolyCEGS PUU has been produced by using PCL-PEG-PCL polyol and glutathione-tetramethyl ester (GSSG-OMe)4 as a chain extender. The LA-Hy- Doxo tethered electrospun membrane has showed a du…

Imatinib-Loaded Micelles of Hyaluronic Acid Derivatives for Potential Treatment of Neovascular Ocular Diseases

In this work, new micellar systems able to cross corneal barrier and to improve the permeation of imatinib free base were prepared and characterized. HA-EDA-C-16, HA-EDA-C-16-PEG, and HA-EDA-C-16-CRN micelles were synthesized starting from hyaluronic acid (HA), ethylenediamine (EDA), hexadecyl chains (C-16), polyethylene glycol (PEG), or L-carnitine (CRN). These nanocarriers showed optimal particle size and mucoadhesive properties. Imatinib-loaded micelles were able to interact with corneal barrier and to promote imatinib transcorneal permeation and penetration. In addition, a study was conducted to understand the in vitro imatinib inhibitory effect on a choroidal neovascularization process…

Biocompatibility and staining properties of CdSe\CdS\SiO2 nanoparticles for in-vitro biomaterials characterization

Semiconductor nanocrystals, known as quantum dots (QDs) display well-tuned emission spectra from ultraviolet to the infrared region. Their photostability is greatly enhanced compared to fluorophores making them suitable for optical bio-imaging. In this work we have studied the cytocompatibility of CdSe\CdS\SiO2 QDs towards bovine articular chondrocytes in order to establish if these nanoparticles could be used as staining system forcells in tissue engineering purposes. Studies of QDs uptake and cell viability were conducted through morphology evaluation and MTS test. The adhesion behavior of chondrocytes deposited onto scaffolds of a derivative of hyaluronic acid functionalized with octadec…

Electrospun biodegradable materials for vascular regenerative medicine

Objectives: There is a rising interest for the development of small-sized blood vessels substitutes. Several studies have been focused on the development of a biodegradable graft temporarily able to substitute the blood vessels and allow their complete regeneration after a certain time. We tried to develop a biodegradable material, with optimal mechanical characteristics and the capacity to allow cells adhesion, differentiation and proliferation by electrospinning to obtain a nano-fibrillar scaffold starting from a polymeric solution. Methods: We report the in vivo application on rats of two new electrospun biodegradable materials, specifically designed to create tubular structures. Both bi…