Search results for "healing"
showing 10 items of 642 documents
Ionic Hydrogel Based on Chitosan Cross-Linked with 6-Phosphogluconic Trisodium Salt as a Drug Delivery System.
2018
[EN] In this work, 6-phosphogluconic trisodium salt (6-PG(-)Na(+)) is introduced as a new aqueous and nontoxic cross-linking agent to obtain ionic hydrogels. Here, it is shown the formation of hydrogels based on chitosan cross-linked with 6-PG(-)Na(+). This formulation is obtained by ionic interaction of cationic groups of polymer with anionic groups of the cross linker. These hydrogels are nontoxic, do not cause dermal irritation, are easy to extend, and have an adequate adhesion force to be applied as polymeric film over the skin. This AWN formulation exhibits a first order release kinetic and can be applied as drug vehicle for topical administration or as wound dressing for wound healing…
In situ forming hydrogels of hyaluronic acid and inulin derivatives for cartilage regeneration.
2014
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…
Secondary Structure-Driven Hydrogelation Using Foldable Telechelic Polymer-Peptide Conjugates.
2018
The synthesis of ABA and ABA' triblock polyethylene glycol-and polysarcosine-peptide conjugates is reported. The A/A' peptides are based on phenylalanine(F)-histidine(H) pentapeptide sequences FHFHF, which promote pH-switchable β-sheet self-assembly into nanorods in water. Only parallel β-sheet-driven folding and intermolecular assembly using ABA triblock polymer-peptide conjugates leads to interstrand cross-linking and hydrogelation, highlighting the impact of supramolecular interactions-directed structure formation at the nano- and mesoscopic level.
Poly(Ethylene Glycol) Dimethacrylates with Cleavable Ketal Sites: Precursors for Cleavable PEG-Hydrogels.
2017
The authors introduce poly(ethylene glycol) (PEG) based macromonomers containing acid-labile ketal moieties as well as terminal methacrylate units that are amenable to radical polymerization. The synthesis of PEGs of different molecular weights (ranging from 2000 to 13 000 g mol-1 with polydispersities <1.15) with a central ketal unit (PEG-ketal-diol) and their conversion to PEG-ketal-dimethacrylates (PEG-ketal-DMA) is introduced. Degradation rates of both PEG-ketal-diols and PEG-ketal-DMA are investigated by in situ 1 H NMR kinetic studies in deuterated phosphate buffer. Hydrogels containing 0, 5, or 10 wt% of PEG-ketal-DMA and 100, 95, or 90 wt% of PEG-DMA, respectively, are synthesized a…
Physicochemical and Rheological Characterization of Different Low Molecular Weight Gellan Gum Products and Derived Ionotropic Crosslinked Hydrogels
2021
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…
Tuning the life-time of supramolecular hydrogels using ROS-responsive telechelic peptide-polymer conjugates
2019
Abstract The synthesis of multi-stimuli responsive peptide-poly(ethylene glycol) ABA-type conjugates is reported. The β-sheet encoded intramolecular folding and intermolecular self-assembly into 1D nanorods is based on a phenylalanine(F)-methionine(M)-histidine(H) FMHMHF hexapeptide sequence, and the supramolecular nanorods are stabilised by a shielding corona of hydrophilic PEG polymers. Interstrand crosslinking leads to the formation of physical networks and hydrogels at physiological pH and at room temperature. The thioether functional groups integrate oxidation responsive properties in the supramolecular polymer assemblies. We show that the glucose fuelled and glucose oxidase catalysed …
CONTROLLED RELEASE OF IgG BY NOVEL UV INDUCED POLYSACCHARIDE/POLY(AMINO ACID)HYDROGELS
2009
The development of new protein and peptide drugs needs new delivery systems able to entrap such drugs in safe conditions without affecting their structure and biological activity. In this context, the present work reports a new approach to load IgG, used as a model of therapeutic proteins such as anti-TNF-alpha monoclonal antibodies, into a polymeric system able to release the entrapped IgG in a controlled manner. In particular, new polysaccharide/poly(amino acid) UV induced hydrogels are proposed as colon delivery systems for human IgG. The poly(amino acid), alpha,beta-poly[N-(2-hydroxyethyl)-D,L-aspartamide], has been functionalized with methacrylic anhydride, while the polysaccharide, in…
Controlled loading and release of beta-lactoglobulin in calcium-polygalacturonate hydrogels
2020
International audience; We show here how the structure of polygalacturonate (polyGalA) hydrogels cross-linked by Ca2+ cations via external gelation controls the loading and the release rate of betalactoglobulin (BLG), a globular protein. Hydrogels prepared from a polyGalA/BLG solution are found similar to those obtained from a polyGalA solution in our previous study (Maire du Poset, et al. Biomacromolecules 2019, 20(7), 2864-2872): they exhibit similar transparencies and gradients of mechanical properties and polyGalA concentration. The nominal BLG/polyGalA ratio of the mixtures is almost recovered within the whole mixed hydrogel despite such strong concentration gradients, except in the pa…
pH-responsive physically and chemically cross-linked glutamic-acid-based hydrogels and nanogels
2018
Abstract Given the great demand for polymers prepared from renewable materials, the synthesis of a glutamic-acid-based hydrogel by solution and inverse miniemulsion polymerization is herein presented. Free radical initiated homopolymerizations of N-acryloyl- l -glutamic acid (l- AGA) resulted in either a readily water-soluble polymer or a physically cross-linked hydrogel, being the formation of physical cross-linking junctions closely related to monomer concentration and mixture viscosity. Chemically cross-linked poly( l -AGA-co-BIS) hydrogels were also synthesized by copolymerization of l -AGA and N,N′-methylenebis(acrylamide) (BIS). Both poly (l- AGA) and poly( l -AGA-co-BIS) swelling beh…
Novel hydrogels based on a polyasparthydrazide. Synthesis and characterization
2000
α,β-polyasparthydrazide (PAHy), a synthetic water-soluble biocompatible polymer, was chemically crosslinked with ethyleneglycol diglycidylether (EGDGE), in order to obtain water swellable microparticies. These were characterized by means of FT-IR spectrophotometry and by means of particle size distribution analysis. The mean pore size of the prepared gels as various crosslinking ratios and the fractal dimensions were determined by light scattering measurements. Swelling measurements gave evidence of the high affinity of PAHy-EGDGE microparticles towards aqueous media at different pH values. The physical state of the prepared networks was evaluated by means of X-rays diffractometry and therm…