Confined coordination regulation of rhodium in organosilica active framework for enhanced photothermal-enzymatic diabetic wound healing.

The modulation and alteration of metal coordination structure is intricately associated with their biological activity. However, the precise control of metal active site in a matrix and thereby enhance the biological activity remains a great challenge. Herein, a convenient "reduction-mediated coordination regulation" strategy was proposed to construct novel rhodium-oxygen clusters in confined organosilica active framework ([RhO3]NC-FOMs) with enhanced photothermal-enzymatic properties for efficient and safe diabetic wound healing. Results revealed that coordination structure of Rh in organosilica-based matrix can be easily adjusted from [RhS2]NC-FOMs to [RhO3]NC-FOMs by changing the reactive conditions from neutral to reductive environment. Simultaneously, the confined effect in physical space ensured uniform and stable [RhO3] coordination structure. Compared with [RhS2]NC-FOMs and other reported Rh-based materials, [RhO3]NC-FOMs demonstrated superior photothermal conversion efficiency exceeding 80% under 808 nm laser, along with remarkable POD/CAT/SOD-like multi-enzymatic activities, thereby enhancing infected diabetic wound healing. This work provides a simple and effective strategy to regulate metal coordination structure for promising therapeutic applications.