Sprayable Berberine–Silk Fibroin Microspheres with Extracellular Matrix Anchoring Function Accelerate Infected Wound Healing through Antibacterial and Anti-inflammatory Effects

The conventional method of applying local medications for treating wound infections is often ineffective because of the dilution of drugs by the excess wound exudate. In addition, there have been insufficient studies investigating the adhesion between drug-loaded nanomaterials and cells or tissue. To address this intractable problem, berberine-silk fibroin microspheres (Ber@MPs) with an extracellular matrix-anchoring function were developed in this study. The microspheres were prepared from silk fibroin using the polyethylene glycol emulsion precipitation method. Subsequently, berberine was loaded onto the microspheres. Our results revealed that Ber@MPs firmly anchored to cells, continuously releasing berberine in the microenvironment. Moreover, both Ber@MPs and Ber@MPs-cell complexes exerted a strong and long-lasting antibacterial effect against Staphylococcus aureus and Staphylococcus epidermidis in the microenvironment, despite the large amount of wound exudate. In addition, Ber@MPs effectively resisted the inflammatory response induced by lipopolysaccharides and accelerated the migration of fibroblasts and neovascularization of endothelial cells cultured in inflammation-induced media. Finally, the in vivo experiments confirmed that the Ber@MP spray accelerated the healing of infected wounds via its antibacterial and anti-inflammatory effects. Therefore, this study provides a novel strategy for treating infected wounds in the presence of excess exudate.