Photothermal 2D Nanosheets Combined With Astragaloside IV for Antibacterial Properties and Promoting Angiogenesis to Treat Infected Wounds

Bacterial infection, inflammatory disorder, and poor angiogenesis of tissue in chronic wounds are the main reasons why wounds are difficult to heal. In this study, a novel MSN-PEG@AS/BP nano-spray was designed to solve these issues. Astragaloside IV (AS) was loaded in mesoporous silica nanoparticles (MSN) to enhance angiogenesis and regulate inflammation, and the two-dimensional (2D) nanosheet black phosphorus (BP) was used to kill bacteria through a photothermal effect. Under thermal decomposition, the covalent bond of polyethylene glycol (PEG) was broken, releasing AS to promote the proliferation of fibroblasts, the formation of blood vessels, and the resolution of inflammation. AS can promote the polarization of the anti-inflammatory (M2) macrophage phenotype to enhance the deposition of extracellular matrix and the formation of blood vessels. Besides, BP showed a significant photothermal effect and nearly 99.58% of Escherichia coli and 99.13% of Staphylococcus aureus were killed in an antibacterial study. This nano-spray would be a novel therapeutic agent for infected wound treatment.