Search results for "healing"
showing 10 items of 642 documents
Biodegradable and pH-sensitive hydrogels for potential colon-specific drug delivery: Characterization and in vitro release studies
2008
A novel pH-sensitive and biodegradable composite hydrogel, based on a methacrylated and succinic derivative of dextran, named Dex-MA-SA, and a methacrylated and succinic derivative of alpha,beta-poly( N-2-hydroxyethyl)- DL-aspartamide (PHEA), named PHM-SA, was produced by photocross-linking. The goal was to obtain a colon-specific drug delivery system, exploiting both the pH-sensitive behavior and the colon-specific degradability. The hydrogel prepared with a suitable ratio between the polysaccharide and the polyaminoacid was characterized regarding its swelling behavior in gastrointestinal simulated conditions, chemical and enzymatic degradability, interaction with mucin, and cell compatib…
Operational Procedures in the Theory of the Drug Release from Chitosan Hydrogels
2018
We build a theoretical model based on a generalization of harmonic applications of Misner-type. It results a sine-Gordon type fractal differential equation whose elliptical solutions can describe, through a convenient choice of fractal dynamic constants, various modes of drug release. Thus, the entire class of empirical models (Higuchi, Korsmeyer-Peppas, Peppas-Sahlin) describing the drug release processes can be dispensed with.
Ionic tactile sensors as promising biomaterials for artificial skin: Review of latest advances and future perspectives
2021
Abstract Ionic tactile sensors (ITS) are an emerging subfield of wearable electronics, capable of mimicking the human skin, including not only the typical anisotropic structure, mechanical behaviour, and tactile functions but even the mechanosensitive ionic channels that are crucial for the human sense of touch. With the rapid development of intelligent technology, such bioinspired materials constitute the core foundation of intelligent systems and are a candidate to be the next generation e-skins, offering a more accurate and evolved biointerface. In the latest years, a wealth of novel ultra-stretchable ITS was proposed, progressively refining the choice of soft materials, including ion ge…
Production and physicochemical characterization of a new amine derivative of gellan gum and rheological study of derived hydrogels
2020
The production of an amine derivative of gellan gum, named GG-EDA, was here obtained by functionalizing the polysaccharide backbone with pendant ethylenediamine moieties. The obtained derivative was characterized by spectroscopic, colorimetric, chromatographic and rheological analyses to study the effect of the free amino groups on the physicochemical properties of the macromolecule. A titration experiment was conducted to study the acid-base dissociation constants in aqueous media for the carboxylic and amino groups in the GG-EDA and to shed light on the possibility that the derivative shows a polyampholyte structure under physiological conditions. The rheological analysis conducted on bot…
Pulsatile protein release and protection using radiation-crosslinked polypeptide hydrogel delivery devices
2011
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…
Polyaspartamide based hydrogel with cell recruitment properties for the local administration of hydrophobic anticancer drugs
2019
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…
Poly(methyl ethylene phosphate) hydrogels
2020
Abstract A degradable and water-soluble polyphosphoester (PPE), namely poly(methyl ethylene phosphate)-dimethacrylate (PMEP-DMA), was synthesized and crosslinked by UV irradiation to prepare PPE-hydrogels. Hydrogels with 10 and 15 wt% of PMEP were prepared after UV-irradiation with an additional 0.2 wt% of photoinitiator. The colorless and transparent PPE hydrogels were studied for their swelling and water uptake. The rheological analysis demonstrated their viscoelastic behavior. The PPE hydrogels were compared to poly(ethylene glycol) (PEG) hydrogels prepared from PEG-macromonomers of similar degrees of polymerization. Hydrolysis experiments proved a successful disintegration of the PPE hy…
Self-reporting hydrogels rapidly differentiate among enterohemorrhagic Escherichia coli (EHEC) and non-virulent Escherichia coli (K12)
2016
Abstract We report on the development of an autonomously reporting indicator hydrogel for the rapid and selective detection of enzymes secreted by the food-borne biosafety level 3 pathogen enterohemorrhagic Escherichia coli (E. coli) O157:H7 (EHEC) and the differentiation of this pathogen from the non-virulent E. coli strain K12. To introduce the sensing functionality, chitosan hydrogel films were equipped with fluorogenic substrates for the detection of α-galactosidase (α-Gal) and β-galactosidase (β-Gal), which are secreted by E. coli O157:H7, and β-glucuronidase (β-GUS), which is produced by the non-virulent E. coli K12 strain, but not by E. coli O157:H7, respectively. In the presence of …
BIOADHESIVE PROPERTIES OF A POLYAMINOACIDIC HYDROGEL: EVALUATION BY ATR FT-IR SPECTROSCOPY
2005
The bioadhesive properties of a novel chemical hydrogel based on a polymer of protein-like structure, have been investigated by using ATR FT-IR spectroscopy. In particular, the copolymer PHG obtained by partial derivatization of PHEA with GMA was chemically crosslinked by UV irradiation at 313 nm. Crosslinked PHG was treated with water to obtain a swelled sample, named PHG-UV gel, that was brought into contact with a phosphate buffer/citric acid solution at pH 7.0 in the absence or in the presence of mucin at various concentrations (0.01, 0.1 and 1 wt.-%). Preliminary dynamic swelling studies have evidenced the occurrence of an interaction between the PHG-UV gel and the glycoprotein. This r…
UV-photocrosslinking of inulin derivatives to produce hydrogels for drug delivery application.
2005
In this work, INU, a natural polysaccharide, has been chemically modified in order to obtain new photocrosslinkable derivatives. To reach this goal, INU has been derivatized with MA thus obtaining four samples (INU-MA derivatives) as a function of the temperature and time of reaction. An aqueous solution of the derivative INU-MA1 was irradiated by using a UV lamp with an emission range from 250 to 364 nm and without using photoinitiators. The obtained hydrogel showed a remarkable water affinity but it underwent a partial degradation in simulated gastric fluid. To overcome this drawback, INU-MA 1 was derivatized with SA thus obtaining the INU-MA1-SA derivative designed to produce a hydrogel …