The stability of chitosan with a degree of deacetylation (DD) of 88 and 81% was investigated in solution during storage for 60 days at various temperatures (60, 28, and 58C) and acid concentrations (0.8M, 0.2M, and 0.1M). The first-order rate constant of chain hydrolysis of 88%DD chitosan at 608C was about 1.4 times higher than that of the 81%DD sample. At 288C, the rates of hydrolysis for both chitosan samples were four to five times lower than those at 608C and are similar. At 58C, chain degradation was not significant. Although acetic acid caused significantly higher (P 0.05) chain scission than formic acid, no significant difference of rate change was observed among three different acid concentrations. Reprecipitation of dissolved chitosan was applied for its purification and to transfer dissolved chitosan to the solvent used to measure its molecular weight. Reprecipitation resulted in slightly lower molecular weight (P 0.05) for both 88%DD and 81%DD samples. The molecular weight of chitosan before and after reprecipitation had good linear relationship (r 2 > 0.9).
Clinical treatment of orthopaedic tissue injuries often involves the use of titanium and titanium alloys with considerable research focusing on the surface modification of these materials. Chitosan, the partly deacetylated form of chitin, is one of the materials under investigation as surface coating for orthopaedic implants in order to improve osteo-integration and cellular attachment. In this study, we determined the effects of the degree of deacetylation (DD) of chitosan membranes on attachment, proliferation and osteogenic differentiation of MC3T3-E1 mouse preosteoblasts. Chitosan membranes were coated with fibronectin to promote biocompatibility and cellular attachment. Membranes were characterized in terms of wettability and surface topography using water contact angle measurements and atomic force microscopy. The results in this study indicate that the surface roughness and fibronectin adsorption increase with increased DD. A higher DD also facilitates attachment and proliferation of cells, but no induction of spontaneous osteogenic differentiation was observed. Lower DD chitosan membranes were successfully prepared to sustain attachment and were modified by crosslinking with glutaraldehyde to promote long-term studies. The chitosan membranes used in this study are suitable as a potential coating for titanium implants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.