Hollow-Tube-Whisker-Modified Biphasic Calcium Phosphate Ceramics Loaded with SDF-1α and EPCs for Steroid-Induced Osteonecrosis of Femoral Head

Abstract

Steroid-induced osteonecrosis of the femoral head (SONFH) remains a significant challenge in orthopedic clinical treatment. In this study, a novel 3D hollow-tube-whisker-modified biphasic calcium phosphate ceramic (H-BCP) is successfully fabricated using an in-situ growth technique. Compared to conventional BCP ceramics, H-BCP exhibited increased specific surface area, enhanced mechanical strength, and improved biocompatibility. Utilizing the hollow-tube whisker structure, H-BCP is functionalized with stromal cell-derived factor-1α (SDF-1α) to construct the H-BCP@SDF-1α sustained-release system. In vitro studies demonstrated that H-BCP@SDF-1α effectively recruited bone marrow stromal cells (BMSCs), promoted their osteogenic differentiation, and supported the angiogenic differentiation of endothelial progenitor cells (EPCs). Furthermore, EPC-loaded H-BCP@SDF-1α (H-BCP@SDF-1α/EPC) is used to construct vascularized tissue-engineered bone and implanted into a SONFH rabbit model following core decompression surgery. At 12 weeks post-surgery, animals implanted with H-BCP@SDF-1α/EPC exhibited significant new bone formation, bone integration, and in situ revascularization. Additionally, it is found that H-BCP@SDF-1α/EPC activated the PI3K/AKT signaling pathway in BMSCs, upregulating osteogenic gene expression. This study explores a novel material system integrating mechanical support, bioactivity, and drug delivery, offering a promising approach for SONFH treatment.