Controlled release of BMP-2 by chitosan/γ-PGA polyelectrolyte multilayers coating on titanium alloy promotes osteogenic differentiation in rat bone-marrow mesenchymal stem cells

• We prepared chitosan/γ-poly-glutamic acid polyelectrolyte multilayers on Ti6Al4V.
• 30 layers of polyelectrolyte were spun coated and loaded with BMP-2.
• The coating lasted for 45 days and sustained release BMP-2 for 5 days.
• In vitro study proved the coating promoted osteogenic differentiation of rBMSCs.

The excellent biocompatibility and mechanical properties of titanium alloys have led to their wide-scale application in orthopedic implants. Appropriate surface treatment of these alloys can greatly improve cellular attachment as well as interactions between implants and tissue. This paper reports on the preparation of polyelectrolyte multilayers (PEM) coating comprising chitosan and gamma-poly(glutamic acid) on a Ti6Al4V substrate via spin-coating. Bone morphogenetic protein 2 was then loaded directly into the coating. Following sample preparation, we performed in vitro studies using SD rat bone-marrow mesenchymal stem cells (rBMSCs) to investigate the biological effects of the coating. Our results demonstrate that this chitosan/γ-PGA PEM coating is highly stable and does not have any adverse effects on rBMSCs. The proposed coating proved highly effective in carrying and enabling the gradual release of BMP-2. At day 14, the coated samples presented osteogenic differentiation far exceeding that of the non-coated samples. After co-culturing for 21 days, the calcium content in the PEM coating group was double that of the non-coated group, which is a clear indication of enhanced cellular mineralization.

Chitosan/γ-poly-glutamic acid polyelectrolyte multilayers coating was prepared on Ti6Al4V substrate with bone morphogenetic protein 2 loaded. 30 layers of polyelectrolyte were spun coated. The coating lasted for 45 days and sustained release BMP-2 for 5 days ex vivo. Results of in vitro studies using SD rat bone-marrow mesenchymal stem cells proved that the coating promoted osteogenic differentiation of cells.Figure optionsDownload high-quality image (47 K)Download as PowerPoint slide