Hydrogel Microsphere-Encapsulated Bimetallic Nanozyme for Promoting Diabetic Bone Regeneration via Glucose Consumption and ROS Scavenging.

The healing of bone defects among diabetic patients presents a critical challenge due to the pathological microenvironment, characterized by hyperglycemia, excessive reactive oxygen species (ROS) production, and inflammation. Herein, multifunctional composite microspheres, termed GMAP are developed, using a microfluidic technique by incorporating Au@Pt nanoparticles (NPs) and GelMA hydrogel to modulate the diabetic microenvironment for promoting bone regeneration. The GMAP enables the sustained release of Au@Pt NPs, which function as bimetallic nanozymes with dual enzyme-like activities involving glucose oxidase and catalase. The synergistic effect allows for efficient glucose consumption and ROS elimination concurrently. Thus, the GMAP effectively protects the proliferation of bone marrow mesenchymal stem cells (BMSCs) under adverse high-glucose conditions. Furthermore, it also promotes the osteogenic differentiation and paracrine capabilities of BMSCs, and subsequently inhibits inflammation and enhances angiogenesis. In vivo diabetic rats bone defect model, it is demonstrated that GMAP microspheres significantly improve bone regeneration, as verified by micro-computed tomography and histological examinations. This study provides a novel strategy for bone regeneration by modulating the diabetic microenvironment, presenting a promising approach for addressing the complex challenges associated with bone healing in diabetic patients.