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.