Functional metal nanozyme-hydrogel for biomedical applications

The metal nanozyme-hydrogel composite system, as a new class of soft intelligent biomaterial, has attracted much attention due to its great potential in simulating the activity of natural enzymes, regulating the pathological microenvironment and achieving synergistic treatment. Metal nanozymes (such as precious metals, transition metal oxides, metal-organic frameworks, etc.) can simulate the activities of various redox enzymes and precisely regulate the homeostasis of reactive oxygen species. The hydrogel matrix provides it with an ideal biocompatible scaffold, a controllable release platform and a macroscopic functional form. The combination of the two endows the composite material with multifunctional synergy. This review systematically summarizes the construction strategies of metal nanozyme-hydrogel systems, with a focus on elaborating the engineering design of nanozymes, the design mechanism of hydrogel matrices, and the application of advanced manufacturing technologies such as three-dimensional printing and injectable gels in achieving macro-structure regulation. Based on this, this article delves deeply into the key applications of this composite system in the biomedical field, including reshaping the tumor microenvironment to enhance combined therapy, comprehensive treatment of infectious wounds (especially diabetic wounds), and achieving anti-inflammatory and repair effects in functional tissues such as osteoarthritis and intestinal inflammation. Finally, we analyzed the core challenges faced by this field and looked forward to its future development direction, aiming to provide new ideas for the design and clinical transformation of the next generation of intelligent biomaterials.