Cu-doped MOF-based nanocomposites with acidity-triggerable aggregation for precise photothermal/chemokinetic combined therapy

Precisely targeting the site of bacterial infection while reducing harm to healthy tissues has turned into the primary aim of bacterial infection treatment. Based on this background, an acidity-triggered aggregation nanomaterial Cu2+/ZIF-8@PDA-GCS (CZPG) based on bimetallic doped metal-organic frameworks was designed. The zinc-based metal-organic framework doped with Cu2+, namely Cu2+/ZIF-8 (CZ), was first synthesized, followed by modification with polydopamine (PDA) and glycol chitosan (GCS) to endow the CZ with photothermal properties and pH-sensitive charge characteristics, respectively. Under normal physiological conditions, the potential value of CZPG is approximately neutral, and it shows poor affinity to normal tissue cells, but the surface potential of CZPG flips to positive potential at the site of acidic bacterial infection. This allows CZPG to aggregate and adhere on the surface of negatively charged bacteria to ensure the spatial accuracy of CDT/PTT and thus enhance the antibacterial effect.