Kinetics and isotherm of fibronectin adsorption to three-dimensional porous chitosan scaffolds explored by ¹²⁵I-radiolabelling

Characterization of Chitosan-Based Scaffolds Seeded with Sheep Nasal Chondrocytes for Cartilage Tissue Engineering

The treatment of cartilage defect remains a challenging issue in clinical practice. Chitosan-based materials have been recognized as a suitable microenvironment for chondrocyte adhesion, proliferation and differentiation forming articular cartilage. The use of nasal chondrocytes to culture articular cartilage on an appropriate scaffold emerged as a promising novel strategy for cartilage regeneration. Beside excellent properties, chitosan lacks in biological activity, such as RGD-sequences. In this work, we have prepared pure and protein-modified chitosan scaffolds of different deacetylation degree and molecular weight as platforms for the culture of sheep nasal chondrocytes. Fibronectin (FN) was chosen as an adhesive protein for the improvement of chitosan bioactivity. Prepared scaffolds were characterised in terms of microstructure, physical and biodegradation properties, while FN interactions with different chitosans were investigated through adsorption-desorption studies. The results indicated faster enzymatic degradation of chitosan scaffolds with lower deacetylation degree, while better FN interactions with material were achieved on chitosan with higher number of amine groups. Histological and immunohistochemical analysis of in vitro engineered cartilage grafts showed presence of hyaline cartilage produced by nasal chondrocytes.

New Silk Fibroin-Based Bioresorbable Microcarriers

We fabricated bioresorbable microcarriers from water solution of Bombyx mori silk fi broin. The microcarriers are 3D structures with intricate surface and pores allowing penetration of culture medium, gas exchange, and cell adhesion. Fibroin molecules form hydrophobic structures and normally have a negative charge, which stimulates migration, but inhibits cell adhesion and makes it less effective. In order to improve adhesion efficiency and velocity, gelatin (hydrophilic biopolymer with integrin-recognizing RGD sequence) was added to the microcarrier composition. The resultant bioresorbable microcarriers support adhesion and proliferation of 3T3 murine fibroblasts.