Use of Electrostatic Layer-by-layer Deposition 2ith Chitosan and Alginate in Testing Chitosan’s Potential In Drug Delivery

摘要

Biodegradable polysaccharides such as chitosan and alginate have attracted great interest owing to their widespread uses in biomedical and pharmaceutical applications. Thanks to the excellent biocompatibility and biodegradability, chitosan has become an exciting and promising biomaterial for tissue engineering, wound dressing, as well as delivery of the encapsulated proteins3 and peptide drugs. Chitosan is a linear copolymer composed of randomly distributed N-acetyl-D-glucosamine and D-glucosamine with a pKa ~ 6.3. (Figure 1) Alginate is a block copolymer with β-D-mannuronate (M) and α-L-guluronate (G) components, interspersed with regions of alternating structure (MG-blocks). (Figure 1) The carboxylic acid group in alginate gives a pKa value ~ 3.5. So far, the incorporation of chitosan and alginate into microcapsule system has been extensively investigated with respect to fundamental research and the potential uses in future clinical trial applications. The mechanical stability and permeability are two major concerns for the fabrication of the chitosan/alginate microcapsules. In particular, the preparation of such microscapsules through layer-by-layer (LbL) assembly affords highly tunable permeability or porosity and therefore offered a competitive and attractive method for controlled drug release.