Study On Preparation And Properties Of Chitosan/Chitosan Derivative Composite Membranes

Chitin and chitosan with unique chemical structure are renewable and natural macromoleculer compounds, which are nontoxic, biocompatible, biodegradable. These biopolymers, which have antiseptic and antibacterial functions, are easily modified and could be used as biomedical macromolecular materials. Modifications on chitosan can effectively improve the performances of it to meet different demands. For example, carboxymethyl chitosan is getting more application in medication field as a result of excellent water-solubility and moisture-retention ability. Quaternized chitosan has wide foreground due to its intensification of moisture-absorption antimicrobial ability and hemostasia function. Composites of chitosan and chitosan derivatives should be novel materials of better performances.This paper summarized the research developments of artificial skin and the applications of chitosan derivatives on artificial skin. Chitosan/chitosan derivatives composite membranes were prepared. The structure and properties of composite membranes were studied. The influences of preparation conditions on intension water absorption and antimicrobial ability of composite membranes were discussed. Animal experiments were carried out to discuss effects of composite membranes as skin substitutes.The main contents and conclusions of this paper are described as follows:(1) Chitosan/quaternized chitosan composite membranes were prepared by casting 2-Hydroxypropyltrimethyl ammonium chloride chitosan (HACC ) on chitosan membrane with glutaraldehyde as crosslinking agent. The influence of the degree of quaternization of chitosan(DS) and the amounts of glutaraldehyde (DC ) on properties of composite membranes was discussed. Drug controlling release properties were studied by loading ciprofloxacin on composite membranes. The tensile strength of composite membranes was first increased and then decreased with increasing of DC, the maximum tensile strength was reached when the amount of glutaraldehyde in quaternized chitosan was 0.2%. Water uptaking capacity and antibacterial activities were increased as DS is increased and reduced as DC is increased. The amount of ciprofloxacin loaded on the membranes was decreased with increasing of DS and DC. The releasing time of ciprofloxacin from the membrane can reach 180 hours.(2) Chitosan/carboxymethyl chitosan bilayer composite membranes were prepared by casting carboxymethyl chitosan(CMCS) on chitosan membrane with glutaraldehyde as crosslinking agent. The influence of the deacetylation degree(DD) and substitution degree(DS) of carboxymethyl chitosan, the amounts of glutaraldehyde, on properties of compositemembranes was discussed. Drug controlling release property was studied by loading ciprofloxacin on composite membranes. Results showed that the tensile strength of composite membranes reached maximum value when the content of glutaraldehyde in carboxymethyl chitosan was 0.05%. Water uptaking capacity reached maximum value when DD was 50%. The antibacterial activity of composite membranes reached maximum value when DS was 0.4. The amounts of ciprofloxacin loaded on the membranes increased with increasing of DS and DC. The releasing time of ciprofloxacin from the membrane can reach 150 hours.(3) Chitosan/carboxymethyl chitosan composite membranes were prepared by dipping the chitosan membrane with low-molecular-weight carboxymethyl chitosan solution. The composite membranes were characterized by Fourier transform infrared(FT-IR) and scanning electron microscope(SEM). The influences of molecular weight of carboxymethyl chitosan on tensile strength water absorption and antimicrobial ability of composite membranes were discussed. Results showed that carboxymethyl chitosan with molecular weight under 8000 can enter into chitosan molecule chains and improve tensile strength and water absorption of chitosan membrane. Carboxymethyl chitosan with high molecular weight has better restrain effects on gram-positive bacterium while carboxymethyl chitosan with low molecular weight has better restrain effects on gram-negative bacterium.(4)Chitosan/carboxymethyl chitosan bilayer composite membranes and Chitosan/low-molecular-weight carboxymethyl chitosan composite membranes were prepared to test their wound healing effects by animal experiments . Results showed chitosan/carboxymethyl chitosan composite membranes have effects on the wound healing of animals. The molecular weight of carboxymethyl chitosan is smaller, the effects of wound healing is better.