A chitosan-based multilayered scaffold for multi-tissue regeneration

Orthopedic tissue engineering usually refers to the restitutio ad integrum of different but uninterrupted regions (ligament, fibrocartilage, bone and skin) and it often employs scaffolds to promote regeneration. Ideally, a scaffold should acts as clot retention device, space maintainer, with a fine-tuned structure in harmony with surrounding tissues. Our aim was the synthesis of a resorbable, sponge-like and multi-layered chitosan scaffold, suitable for contextual multi-tissue regeneration. A porous and multi-layered scaffold was produced by cross-linking chitosan with genepin and further lyophilization. Chitosans with different molecular weights were exploited in order to modulate the properties of the multi-layered structure: an interface for cutaneous side was made of low molecular weight (LMW) chitosan, while a layer for bone was composed of medium molecular weight (MMW) chitosan. A specific structure with oriented pores, for ligament fibers, was obtained by MMW chitosan electrodeposition. A three-layered highly porous, sponge-like and cross-linked structure was obtained. The MMW chitosan layer, for bone interface, revealed a better stability at in vitro degradation test, in presence or not of lysozime, and an increased resistance to compression. The oriented pore structure for ligament was synthesized. Different pore sizes could be produced. All parts of the construct were cytocompatible. The scaffold displayed tunable structure and physical-mechanical properties in harmony with different tissues to be regenerated, suggesting a promising approach for multi-tissue regeneration.