Structural characterization of new chitosan-containing hybrid bioactive gels

The aim of the present study is the characterization of a new hybrid biomaterial obtained by combining a natural biopolymer, i.e chitosan, with an inorganic phase previously modified by the addition of calcium and phosphate ions. To this issue, we have prepared different chitosan-containing samples and tested both their solvent permeability and ion release capability. Data reveal the occurrence of a severe swelling process, whose kinetics is slowed down by the presence of increasing amounts of chitosan. Structural tests were performed by employing infrared spectroscopy and weight change measurements; further, the changes induced by chitosan on the biogel matrix were determinated by the use of confocal microscopy. Our results demonstrate that chitosan modifies the overall chemical structure of the inorganic phase, and reduces leaching effects without producing relevant interferences to the formation of the apatite layer on the bioactive gel surface. By defining more accurate limits to biopolymer incorporation into the bioactive gels, our data provide new insights on the potential offered by chitosan for incorporation into new biocompatible materials. (c) 2005 Elsevier B.V. All rights reserved.