Targeted hot ion therapy of infected wound by glycol chitosan and polydopamine grafted Cu-SiO2 nanoparticles

Quick and effective elimination of drug-resistant bacteria and simultaneous repairing the infectious tissue remain challenging in clinics. In this study, multifunctional glycol chitosan and polydopamine coated copper-doped mesoporous silica (MCS@PDA@GCS) nanoparticles with near-infrared (NIR) photothermal conversion ability and bacteria-targeting property are prepared. When infection occurred, the environment becomes acidic, and MCS@PDA@GCS nanoparticles with pH-sensitive could be accumulated on the surface of the bacteria. The NIR light-induced heating and Cu ions released from MCS@PDA@GCS nanoparticles created a distinct "hot ions effect", showing high-efficiency, quick and long-term inhibition of bacteria (methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli)) as well as biofilm. In ad-dition, the MCS@PDA@GCS nanoparticles with "mild hot ions effect" could induce macrophages polarization into a pro-inflammatory M1 phenotype, resulting in the clearance of infection through the immune-anti-bacterial effect. Moreover, the "mild hot ions effect" endows MCS@PDA@GCS nanoparticles with remarkable bioactivity, which stimulates the migration and angiogenesis of endothelial cells. The in vivo results con-firmed that MCS@PDA@GCS nanoparticles with laser irradiation could efficiently remove bacteria and significantly promote wounds closure, epithelization and angiogenesis during infectious wound healing process. (c) 2021 Elsevier Ltd. All rights reserved.