Polydopamine-mediated immobilization of BMP-2 onto electrospun nanofibers enhances bone regeneration

Dealing with bone defects is a significant challenge to global health. Electrospinning in bone tissue engineering has emerged as a solution to this problem. In this study, we designed a PVDF-b-PTFE block copolymer by incorporating TFE, which induced a phase shift in PVDF fromαtoβ, thereby enhancing the piezoelectric effect. Utilizing the electrospinning process, we not only converted the material into a film with a significant surface area and high porosity but also intensified the piezoelectric effect. Then we used polydopamine to immobilize BMP-2 onto PVDF-b-PTFE electrospun nanofibrous membranes, achieving a controlled release of BMP-2. The scaffold's characters were examined using SEM and XRD. To assess its osteogenic effectsin vitro, we monitored the proliferation of MC3T3-E1 cells on the fibers, conducted ARS staining, and measured the expression of osteogenic genes.In vivo, bone regeneration effects were analyzed through micro-CT scanning and HE staining. ELISA assays confirmed that the sustained release of BMP-2 can be maintained for at least 28 d. SEM images and CCK-8 results demonstrated enhanced cell viability and improved adhesion in the experimental group. Furthermore, the experimental group exhibited more calcium nodules and higher expression levels of osteogenic genes, including COL-I, OCN, and RUNX2. HE staining and micro-CT scans revealed enhanced bone tissue regeneration in the defective area of the PDB group. Through extensive experimentation, we evaluated the scaffold's effectiveness in augmenting osteoblast proliferation and differentiation. This study emphasized the potential of piezoelectric PVDF-b-PTFE nanofibrous membranes with controlled BMP-2 release as a promising approach for bone tissue engineering, providing a viable solution for addressing bone defects.