Collagen-Hydroxyapatite Scaffold Platform Incorporating Dimethyloxalylglycine Loaded Polymersomes Decorated with BMP-2 Peptide for Bone Tissue Engineering

Recent advances in the field of nanotechnology have led to the development of platforms for healing or repairing damaged tissues. The present study aimed to provide a bone extracellular matrix (ECM) mimetic platform made of hydroxyapatite and collagen loaded with nanopolymersomes encapsulating dimethyloxalylglycine (DMOG) and decorated with BMP-2 peptide in order to accelerate and increase the differentiation of mesenchymal stem cells to bone tissue.

In this study, polymersome nanoparticles carrying DMOG and targeted with BMP-2 peptide were prepared. The physicochemical properties of nanoparticles were evaluated. Thereafter, it was loaded into collagen-nanohydroxyapatite scaffolds and the expression levels of osteogenic genes OCN and OPN and angiogenic genes vcam, vwf, and kdr were checked in mesenchymal stem cells.

The surface charge and particle size of the synthesized nanoparticles were reported as -6 mv and 141 nm, respectively. The nanoparticles were able to slowly release 35% of the loaded DMOG within 30 days. The results demonstrated that the expression levels of OCN and OPN genes in cells exposed to polymersomes targeted with BMP-2 peptide were 27 and 2 times more than those of non-targeted polymersomes, respectively. In addition, the expression of angiogenic genes, vwf, kdr, and vcam, displayed a significant increase in targeted polymersomes compared to the non-targeted types (11.7-, 12.8-, and 2.17-fold, respectively).

It seems that providing an environment similar to the bone ECM by combining an osteomimetic scaffold made of collagen-nanohydroxyapatite, DMOG as an angiogenic factor, and BMP-2 as the osteogenic factor can be effective in accelerating and increasing the differentiation of mesenchymal stem cells into osteoblasts.