In vitro and in vivo studies of a novel bacterial cellulose-based acellular bilayer nanocomposite scaffold for the repair of osteochondral defects

Bacterial cellulose (BC) is a naturally occurring nanofibrous biomaterial which exhibits unique physical properties and is amenable to chemical modifications. To explore whether this versatile material can be used in the treatment of osteochondral defects (OCD), we developed and characterized novel BC-based nanocomposite scaffolds, for example, BC-hydroxyapatite (BC-HA) and BC-glycosaminoglycans (BC-GAG) that mimic bone and cartilage, respectively. In vitro biocompatibility of BC-HA and BC-GAG scaffolds was established using osteosarcoma cells, human articular chondrocytes, and human adipose-derived mesenchymal stem cells. On subcutaneous implantation, the scaffolds allowed tissue ingrowth and induced no adverse immunological reactions suggesting excellent in vivo biocompatibility. Implantation of acellular bilayered scaffolds in OCD created in rat knees induced progressive regeneration of cartilage tissue, deposition of extracellular matrix, and regeneration of subchondral bone by the host cells. The results of micro-CT revealed that bone mineral density and ratio of bone volume to tissue volume were significantly higher in animals receiving bilayered scaffold as compared to the control animals. To the best of our knowledge, this study proves for the first time, the functional performance of acellular BC-based bilayered scaffolds. Thus, this strategy has great potential for clinical translation and can be used in repair of OCD.