Preparation of Hollow Co-doped ZIF-L-PDA for Synergistic Chemo-Photothermal Biofilm Eradication.

Bacterial infections, especially those triggered by bacterial biofilms, remain a thorny challenge in antibacterial treatment. Metal-organic frameworks (MOFs), as carriers of metal ions that can sustainably release antibacterial ingredients, provide a promising alternative strategy for combating bacterial infections. Although the introduction of metal ions into MOFs is a relatively uncomplicated process, it remains an arduous task to eradicate all pathogenic bacteria with a limited dosage. Herein, an economical and efficient hollow Co-doped ZIF-L-PDA (HZIF-L-PDA (Co)) nanomaterial was synthesized via a simple dopamine-mediated self-assembly reaction. The uniform incorporation of Co and Zn in the ZIF-L skeleton and the polymerization of dopamine were completed through a one-pot method, avoiding complexity and harsh synthesis conditions. Due to the abundant metal nodes of ZIF-L and the photothermal and adhesion ability of polydopamine (PDA), HZIF-L-PDA (Co) can adhere to the bacterial surface and rely on its chemical antibacterial action and photothermal effect to exhibit a synergistic antibacterial effect, causing cell membrane rupture and invagination in Escherichia coli O157:H7 (E. coli O157:H7) and Staphylococcus aureus (S. aureus), respectively. Antibacterial experiments displayed that the sterilization rates of HZIF-L-PDA (Co) driven by near-infrared (NIR) light at low concentration (75 μg/mL) against E. coli O157:H7 and S. aureus were 96.9% and 97.3%, respectively. The HZIF-L-PDA (Co) realized favorable eradication against E. coli O157:H7 mature biofilms, while the therapeutic effect against S. aureus biofilms was limited at the tested low concentration. Overall, we proposed an easily fabricated MOF-based nanocomposite that fought pathogenic bacteria through chemical and photothermal effects, promising as an alternative to antibiotics.