(P 73) Chitosan Scaffold for Bile Duct Reconstructive Surgery

This work aims at the preparation of a novel biodegradable chitosan tube-shaped scaffold intended for bile duct reconstruction. The scope implies the development of a structure, with low permeability to bile, possessing suitable mechanical resistance and potentially able to act as drug delivery system for antimicrobial agents. The goal is pursued by setting up a multilayer tube where one layer is a crosslinked chitosan hydrogel, imposing mechanical resistance and low permeability to bile, while the second layer is a soft biomaterial acting as optimal cell substrate. The latter is constituted by chitosan and excipients (such as sugars and/or phosphate salts) added to a chitosan solutions. These excipients are not recovered in the scaffold upon solidification, however, they interact with chitosan during the hydrogel formation process. For comparative purpose, monolayer scaffolds were prepared as well. The physical properties and the biological features of the prepared scaffolds have been investigated. The new scaffold shows marked different structure and higher biocompatibility in comparison to that obtained from the sole chitosan solution. Multilayer scaffolds are less permeable to bile than monolayer ones. This is due to the more compact structure of the multilayer scaffolds as indicated by their lower porosity. This last characteristic positively influences also the mechanical properties in particular the resistance to surgical suture. The novel material shows beneficial effects on cell culturing: higher rate of cell attachment and doubling, lower cell detachment even 15 days after seeding, a higher cell yield, and an adequate differentiation morphology.