Chitosan–silica hybrid porous membranes

Abstract

Chitosan-silica porous hybrids were prepared by a novel strategy in order to improve the mechanical properties of chitosan (CHT) in the hydrogel state. The inorganic silica phase was introduced by sol-gel reactions in acidic medium inside the pores of already prepared porous scaffolds. In order to make the scaffolds insoluble in acidic media chitosan was cross-linked by genipin (GEN) with an optimum GEN concentration of 3.2 wt.%. Sol-gel reactions took place with Tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) acting as silica precursors. GPTMS served also as a coupling agent between the free amino groups of chitosan and the silica network. The morphology study of the composite revealed that the silica phase appears as a layer covering the chitosan membrane pore walls. The mechanical properties of the hybrids were characterized by means of compressive stress-strain measurements. By immersion in water the hybrids exhibit an increase in elastic modulus up to two orders of magnitude.

Determining the influence of N-acetylation on water sorption in chitosan films

“…In contrary, when immersed in liquid water the water content varies between 250 and 600%. Similar high values have been reported previously (Pandis et al, 2014) for chitosan films. The above behavior is typical for hydrogels and could be explained by taking into consideration that the amount of water absorbed in the form of bulk water is much higher than that forming a homogeneous mixed phase with the hydrogel (Pandis et al, 2011).…”

Porous Polylactic Acid-Silica Hybrids: Preparation, Characterization, and Study of Mesenchymal Stem Cell Osteogenic Differentiation

“…To that aim, the versatile method of sol–gel method was employed using TEOS and GPTMS as the silica precursors. The sol–gel reactions were performed in acidic conditions in order to produce a continuous silica phase covering the pore walls of the membranes . The silica network was produced after the hydrolysis and condensation of TEOS and GPTMS.…”

Nanohybrid organic–inorganic chitosan/dopamine/TiO2 composites with controlled drug-delivery properties

“…33 One of the strategies to controlled release of drugs should be to distribute the drug within 34 a substrate with special chemical, biological, and mechanical characteristics such as chitosan 35 [4,7] alginate [8] chitosan-montmorillonite [9] chitosan-LDH [10] and so on. Chitosan, due to its 36 numerous hydroxyl and amine functionalities and biocompatibility, biodegradability, and 37 haemostatic properties, has been used frequently in drug delivery systems [4,7,9,10]. 38 In addition, use of coatings in medical applications has proven adding various structural 39 and mechanical properties to drug composites such as protection from oxidation and degradation 40 of drug, delay in the release of drug, changing from injection to oral drug use, etc [11][12][13][14].…”