Metal-Phenolic Networks-Reinforced Extracellular Matrix Scaffold for Bone Regeneration via Combining Radical-Scavenging and Photo-Responsive Regulation of Microenvironment.

The limited regulation strategies of the regeneration microenvironment significantly hinder bone defect repair effectiveness. One potential solution is using biomaterials capable of releasing bioactive ions and biomolecules. However, most existing biomaterials lack real-time control features, failing to meet high regulation requirements. Herein, a new Strontium (Sr) and epigallocatechin-3-gallate (EGCG) based metal-phenolic network with polydopamine (PMPNs) modification was prepared. This material reinforces a biomimetic scaffold made of extracellular matrix (ECM) and hydroxyapatite nanowires (nHAW). The PMPNs@ECM/nHAW scaffold demonstrated exceptional scavenging of free radicals and ROS, promoting HUVECs cell migration and angiogenesis, inducing stem cell osteogenic differentiation, and displaying high biocompatibility. Additionally, the PMPNs exhibited excellent photothermal properties, further enhancing the scaffold's bioactivities. In vivo studies confirmed that PMPNs@ECM/nHAW with NIR stimulation significantly promoted angiogenesis and osteogenesis, effectively regulating the microenvironment and facilitating bone tissue repair. This research not only provides a biomimetic scaffold for bone regeneration but also introduces a novel strategy for designing advanced biomaterials. The combination of real-time photothermal intervention and long-term chemical intervention, achieved through the release of bioactive molecules/ions, represents a promising direction for future biomaterial development. This article is protected by copyright. All rights reserved.