Diffusional properties of chitosan hydrogel membranes

Abstract

Chitosan membranes were prepared by a solvent evaporation technique, followed by crosslinking with glutaraldehyde and coating with BSA. The effects of crosslinking and BSA coating on the pore structure of such prepared hydrogel chitosan membranes were determined. The diffusion rates of 12 non-electrolytes ranging in molecular radius between 2.5 and 14 A Ê through the membranes were measured, and the results were interpreted in terms of the capillary pore model and free volume model of solute diffusional transport through hydrogel membranes. Glutaraldehyde crosslinking was found to reduce the membrane water content and consequently the membrane pore size and surface porosity, whereas further BSA coating brought about the opposite effect. The latter effect lessened with an increase in glutaraldehyde pretreatment of the membranes. The optimal chitosan membrane preparation, compromising between the solute¯ux and membrane stability and durability was obtained when the membranes were crosslinked with glutaraldehyde at concentrations between 0.01 and 0.1% (w/w). The knowledge of transport properties and of physical strength of the membranes is of importance for the development of chitosan-based controlled release systems.

Electrochemical lactate biosensor based upon chitosan/carbon nanotubes modified screen-printed graphite electrodes for the determination of lactate in embryonic cell cultures

“…-150 mV versus the pseudo-reference electrode. This is explained as the incorporation of CS biopolymer into the enzymatic composite matrix leads to a more resistive film, due to the low ionic conductivity of the CS biopolymer (Krajewska 2001;Wan et al 2003Wan et al , 2006.…”

Chitosan Hydrogel‐Capped Porous SiO2 as a pH Responsive Nano‐Valve for Triggered Release of Insulin

“…In addition it has bacteriostatic properties and a demonstrated efficacy for the promotion of wound healing. [25,26] Chitosan is a polycationic copolymer of b-(1,4)-linked-2-acetamido-2-deoxy-D-glucopyranose and 2-amino-2-deoxy-D-glucopyranose, and it is obtained by alkaline deacetylation of chitin. The pH response derives primarily from the large number of amino groups on the polymer.…”

Modeling the mass transfers during the elaboration of chitosan‐activated carbon composites for medical applications

“…The mass-transfer coefficient for free convection of component k i can be determined from the empirical correlation given by Yip (25) where Gr is the Grashof number, Sc i is the Schmidt number related to i, D i/g (m 2 /s) is the mutual diffusion coefficient of i in the gas phase, L c (m) the characteristic length of the interface and y air,lm the log-mean mole fraction difference of air. The Schmidt number has its standard definition.…”

“…[24][25][26][27][28] It consists in solubilizing the polymer in an acidic aqueous solution, the acetic acid, most of the time. 29 In a second step, the polymeric solution has to be submitted to a basic media (sodium hydroxide) to induce the gelation.…”