Development of Silk Fibroin/Chitosan Based Porous Scaffolds for Cartilage Tissue Engineering

Abstract

The present research deals with the development of silk fibroin (SF) and chitosan (CS) based microporous 3D scaffolds for cartilage tissue engineering applications. Porous scaffolds prepared from SF/CS blends with varying ratio of SF and CS by freeze drying method were characterized for physicochemical, mechanical and biological properties. Among the various blend ratios, SF/CS with 80:20 blend was found to be the most favourable for achieving certain superior scaffold properties than other SF/CS blends. The scaffold possesses open pore microstructure with interconnected pore network with desired pore size (71-210 μm), average pore size (186±32.2 μm), porosity (82.2±1.3%) and compressive strength (190 ±0.2kPa). Bioactive molecules namely glucosamine sulphate (Glu) and chondroitin sulphate (Chs),the structural components of native cartilage tissue were added individually and in combination with the aim of improving cell supportive and glycosaminoglycan (GAG) secretive properties thereby facilitating cartilage specific ECM production. Thus, SF/CS/Glu and SF/CS/Chs scaffolds with varying percentage of Chs and Glu concentrations were developed. The SF/CS/Glu scaffold with 1% (w/v) Glu was the most favourable composition have pore size of 40-190 μm, average pore size of 104±19.6 μm, 79.6+4.12% porosity and 202 ±12 kPa compressive strength. A marginal improvement in scaffold property was also achieved specifically by the addition of 0.8 % (w/v) Chs. The scaffold possess a pore size of 44-196 μm, average pore size 105±19.5% porosity of 87+2.13% and 204 ±13 kPa compressive strength. In-vitro cell culture study using human mesenchymal stem cell (hMSCs) derived from umbilical cord blood (UCB) has shown an enhanced cell attachment, proliferation and differentiation (GAG assay) with SF/CS/Chs scaffolds than its counterpart SF/CS and SF/CS/Glu scaffolds. An enhanced scaffold porosity, hydrophilicity, cell adhesion and cell proliferation were further achieved by the incorporation both Glu and Chs in combination into SF/CS blend. Moreover, the increased GAG secretion shown by SF/CS/Glu/Chs scaffolds represents the superiority of the scaffold than the other scaffold towards cartilage tissue regeneration. Thus, it has been demonstrated that the scaffold comprising of SF/CS/Glu/Chs is the potential 3D polymer matrix which can be used as a suitable platform for cartilage tissue regeneration.