Crosslinked chitosan-lactide matrices for the controlled delivery of therapeutic agents

Researchers at Stanford have developed methods for preparing photo-, and chemical-, cross-linkable three-dimensional matrices for the controlled delivery of bioactive molecules for therapeutic applications. The matrices can be used for growth factor delivery and for cell delivery. The chitosan-lactide hydrogel combines excellent biocompatibility, protein affinity, and degradability from hydrophilic chitosan, and tunable physical and mechanical properties from hydrophobic lactide. Simple manipulation of chitosan-lactide ratio, UV irradiation time or catalyst concentration can be used to regulate hydrogel properties such as swelling behavior, degradation rate, and spatial as well as temporal distribution of released proteins. The material can be applied to the targeted area as a preformed matrix and also can be gelled in situ via UV light exposure. The technology is currently available for licensing for non-otolaryngology applications only.

In a rat critical size bone defect model, the chitosan-lactide matrix has clearly shown dose dependent efficacy in delivering bone promoting growth factors such as bone morphogenetic protein-2 (BMP-2). When compared to commercially available BMP products, the same dose BMP-2 containing chitosan-lactide matrix demonstrated significantly improved bone healing (85% vs. 50%) due to controlled sustained release of bioagent and improved structural guidance.