Fabrication and evaluation of bone morphogenetic protein-2 microspheres coated black phosphorus nanosheets@polylactic-glycolic acid copolymers scaffold: A multifunctional antibacterial photothermal scaffold for bone regeneration

Clinical bone defects are often caused by high energy injury and are easily complicated by bacterial infection. An ideal bone repair material should promote bone regeneration and prevent bacterial infection. In this study, a multifunctional photothermal scaffold was developed: bone morphogenetic protein-2 (BMP-2)/polylactic-glycolic acid copolymers (PLGA) microspheres were prepared by a double emulsion method and then coated on the scaffolds prepared using a mixture of black phosphorus nanosheets (BPs) and PLGA, to form BMP-2@BPs scaffolds. The structural and photothermal properties of the composite scaffolds were characterized. The BMP2@BPs scaffolds demonstrated good biocompatibility in both in vitro and in vivo experiments. The BMP2@BPs scaffolds promoted osteogenic differentiation through a combination of BMP-2 release and upregulation of the expression of heat shock proteins by the radiation of near-infrared (NIR) light, which further upregulated the expression of osteogenesis-related genes. In addition, BPs demonstrated antibacterial effects under the mediation of NIR, which is beneficial for the prevention of clinical bacterial infections. In summary, the BMP2@BPs scaffold was a multifunctional photothermal scaffold that could accelerate bone regeneration and act against bacteria. This study provides a new perspective for the treatment of bone defects and infectious bone defects.

Automated summary

A multifunctional photothermal scaffold was developed in this study, which could accelerate bone regeneration and combat bacterial infection. The scaffold promoted osteogenic differentiation through BMP-2 release and upregulation of heat shock protein expression mediated by near-infrared light. Additionally, black phosphorus nanosheets exhibited antibacterial effects under the mediation of near-infrared light, which was beneficial for preventing bacterial infections.