Search results for "self-healing"
showing 10 items of 222 documents
Phosphorylation triggered growth of metal phosphate on halloysite and sepiolite nanoparticles: preparation, entrapment in chitosan hydrogels and appl…
2020
The rational design of porous, biomass-derived eco-friendly adsorbents instead of costly synthetic, petroleum-based resins stands as a promising approach to resolving the thorny issue of sewage treatment (for example, by supplying safe water for drinking and irrigation). Herein we explore a straightforward transformation of abundant clay and polysaccharides into highly-reactive water-cleaning adsorbents. Surface-functionalization of sepiolite and halloysite by phosphoryl chloride triggered metal dissolution from the framework (inside of the lumen for halloysite and on the external surface for sepiolite) and the concomitant growth of well-truncated crystalline metal phosphates. These unprece…
Bioactive glass ions induce efficient osteogenic differentiation of human adipose stem cells encapsulated in gellan gum and collagen type I hydrogels
2019
Abstract Background Due to unmet need for bone augmentation, our aim was to promote osteogenic differentiation of human adipose stem cells (hASCs) encapsulated in gellan gum (GG) or collagen type I (COL) hydrogels with bioactive glass (experimental glass 2-06 of composition [wt-%]: Na2O 12.1, K2O 14.0, CaO 19.8, P2O5 2.5, B2O3 1.6, SiO2 50.0) extract based osteogenic medium (BaG OM) for bone construct development. GG hydrogels were crosslinked with spermidine (GG-SPD) or BaG extract (GG-BaG). Methods Mechanical properties of cell-free GG-SPD, GG-BaG, and COL hydrogels were tested in osteogenic medium (OM) or BaG OM at 0, 14, and 21 d. Hydrogel embedded hASCs were cultured in OM or BaG OM fo…
Qualitative and quantitative characterization of the in vitro dehydration process of hydrogel contact lenses
2007
Purpose: To investigate the in vitro dehydration process of conventional hydrogel and silicone-hydrogel contact lens materials. Methods: Eight conventional hydrogel and five silicone-hydrogel contact lenses were dehydrated under controlled environmental conditions on an analytical balance. Data were taken at 1-min intervals and dehydration curves of cumulative dehydration (CD), valid dehydration (VD), and dehydration rate (DR) were obtained. Several quantitative descriptors of the dehydration process were obtained by further processing of the information. Results: Duration of phase I (r 2 5 0.921), CD at end of phase I (r 2 5 0.971), time to achieve a DR of � 1%/min (r 2 5 0.946) were stron…
Dynamic covalent urea bonds and their potential for development of self-healing polymer materials
2019
Self-healing polymer materials have drawn rapidly increasing interest over the last decade, and have been studied and used in an ever-increasing range of applications. Herein, we successfully make the covalent urea bond – a pinnacle of stability due to strong resonance effects – dynamic in nature through mediation of zinc salts. The dynamic covalent character of urea in the presence of zinc ions is confirmed through dissociation reaction experiments and quantum chemical calculations of small-molecule model urea compounds. In line with our experiments, the modelling results suggest that the presence of zinc ions speeds up the reaction of urea dissociation by two orders of magnitude via the f…
A POLYCARBOXYLIC/AMINO FUNCTIONALIZED HYALURONIC ACID DERIVATIVE FOR THE PRODUCTION OF pH SENSIBLE HYDROGELS IN THE PREVENTION OF BACTERIAL ADHESION …
2014
A graft copolymer derivative of hyaluronic acid bearing pendant amino and short polymethacrylate portions (HA-EDA-BMP-MANa) has been employed for the production of a pH sensible vancomycin releasing hydrogel and studied in vitro to test its potential anti adhesive property against Staphylococcus aureus colonization. The copolymer obtained through atom transfer radical polymerization bears chargeable (carboxyl and amino groups) portions and it could be formulated as a hydrogel at a concentration of 10% w/v. The HA-EDA-BMP-MANa hydrogels, produced at three different pH values (5, 6 and 7, respectively), were formulated with or without the addition of vancomycin (2% w/v). The vancomycin releas…
Microparticles derived from marine sponge collagen (SCMPs): preparation, characterization and suitability for dermal delivery of all-trans retinol.
2002
Abstract Collagen microparticles were prepared using marine sponge collagen. For this purpose a previous method by Rossler et al. (J. Microencapsul. 12 (1995) 49) of emulsification and cross-linking of native calf collagen was modified. The modified method for sponge collagen microparticles (SCMPs) achieved a yield of 10%. Scanning electromicroscopic photographs showed spherical particles with a diameter of 120–300 nm and photon correlation spectroscopic measurements indicated particle size range from 126 (±2.9) to 2179 (±342) nm. This broad size distribution was caused by some agglomerates that could not be destroyed by ultrasonication. The surface charge was measured as a function of pH. …
Photocrosslinkable polysaccharide hydrogel composites based on dextran or pullulan-amylose blends with cytokines for a human co-culture model of huma…
2016
Although a large body of research has been devoted to biomaterial development for bone tissue engineering and related medical disciplines in the last few years, novel and optimized materials especially for bone fractures of critical sizes demand continued development. In this respect, polysaccharide-based hydrogels demonstrate beneficial properties and fulfill the main requirements for a bone tissue scaffold as they are hydrophilic, biocompatible, and biodegradable. The aim of the present study was the development of a natural polysaccharide-based scaffold material that can integrate with the host tissue and support bone regeneration. For this purpose, we prepared and investigated two polym…
Hydrogels for potential colon drug release by thiol-ene conjugate addition of a new inulin derivative.
2008
Inulin was chosen as a starting polymer for biocompatible, pH-sensitive and biodegradable hydrogels. Three INUDVSA-TT hydrogels were obtained by crosslinking inulin derivatives with trimethylolpropane tris(3-mercaptopropionate) under varying conditions. The resulting hydrogels were cell compatible, as demonstrated by MTS and trypan blue exclusion assays acting on Caco-2 cells, and were biodegraded by inulinase and esterase, thus suggesting their use as colonic drug delivery systems. 2-Methoxyestradiol, an anti-cancer drug, was soaked in INUDVSA-TT hydrogels and its in vitro release and apoptotic effect on Caco-2 cells were evaluated.
Carbohydrate-supramolecular gels : adsorbents for chromium(VI) removal from wastewater.
2019
Abstract Hypothesis To overcome the contamination of water by heavy metals the adsorption of the pollutant on gel phases is an attractive solution since gels are inexpensive, potentially highly efficient and form a distinct phase while allowing diffusion of the contaminated water throughout the material. This work tests the chromium(VI) adsorbent capacity of new supramolecular gels for Chromium(VI) removal from wastewater. Experiments First hydrophobic imidazolium salts of carbohydrate anions were synthesised as new gelators. Subsequently, they were dissolved in a solvent by heating and, after cooling overnight, to give the formation of supramolecular gels. The properties of the resulting g…
Ciprofloxacin carrier systems based on hectorite/halloysite hybrid hydrogels for potential wound healing applications
2021
The design of multifunctional nanomaterials which can help the healing processes of skin, preventing the bacterial infections, is crucial for the development of suitable therapy for the treatment of chronic lesions. The use of clay minerals in wound healing applications is well documented since the prehistoric period and offers several advantages due to their intrinsic properties. Herein, we report the development of ciprofloxacin carrier systems based on hectorite/halloysite (Ht/Hal) hybrid hydrogels for potential wound healing applications. To achieve this objective firstly the ciprofloxacin molecules were loaded onto Hal by a supramolecular and covalent approach. The so obtained fillers …