Photocrosslinkable Protein Based Hydrogels Enhancing the Scope of Cartilage Tissue Engineering

Abstract

Osteoarthritis (OA) is one of the most common degenerative joint diseases in elderly people, showing the characteristics of the progressive deterioration of articular cartilage, leading to inflammation, pain, and reduced mobility. The avascular and aneural nature of cartilage sets the major challenge in self-healing process. Conventional treatment procedures like autologous cell implantation (ACI), microfracture techniques and other methods fail to completely regenerate healthy articular cartilage, rather leading to the formation of fibrocartilage. As the mechanical strength of fibrocartilage is lower than that of a healthy articular one, degeneration of the cartilage occurs which leads to a further complex inflammatory microenvironment. Protein based hydrogels can serve as a physiologically active framework to solve this problem. Mimicking the composition of extracellular matrix of cartilage tissue, supporting cell differentiation and most importantly integrating with the host tissue can be easily achieved by protein based hydrogels. Chemical crosslinkers can leach out from hydrogels which can create toxicity problems to host. Photocrosslinkable dual modified protein based hydrogel has been developed which can significantly reduce the cytotoxicity which has been studied by live-dead assay, MTT cytotoxicity assay. TNBS assay and NMR studies confirmed the chemical modification of protein components. Modified proteins are combined to form protein composite scaffolds which showed higher elastic modulus of 125±50 KPa where hydrogels containing only protein showed around 17±4.5 KPa. Gel fraction study showed the highest value of 97.10±1.13% in protein composite followed by 97.41±0.66 % and 95.6±1.55% in only protein hydrogels confirming the crosslinking efficiency. Results of MTT cytotoxicity assay were more than 80% in all hydrogels proving biocompatibility. In a nutshell, we have tried to report the potential of modified dual protein based photocrosslinkable hydrogels for cartilage regeneration.