Study on the Antibacterial Properties of Quaternary Ammonium Salts and Pyridine Compounds Synthesized Based on Polyoxometalate Ions

Abstract In this study, phosphotungstic acid (PW 12 ), hexadecyltrimethylammonium bromide (CTAB), and pyridine (Py) were used to synthesize CTAB‐ and Py‐modified phosphotungstic heteropoly acids (CTAB‐PW 12 and Py‐PW 12 ). Their structures were characterized, and antibacterial activity against Staphylococcus aureus ( S. aureus ) was assessed via inhibition zones, minimum inhibitory concentrations (MIC), growth curve, and assays of nucleic acid/protein leakage and micromorphology. The results indicated that Py‐PW 12 exhibited uniform particles (84.9 µm), while CTAB‐PW 12 showed aggregation (85.2 µm) due to hydrophobicity. CTAB‐PW 12 displayed a porous columnar structure enhancing surface area and antibacterial release, whereas Py‐PW 12 had a rough, block‐like morphology promoting bacterial adsorption. MICs of CTAB‐PW 12 and Py‐PW 12 were 325 and 750 µg/mL, respectively. At MIC levels, inhibition rates reached 82.9% (CTAB‐PW 12 ) and 82.0% (Py‐PW 12 ). SEM revealed bacterial structural damage post‐treatment. Mechanistically, both agents disrupted cell membranes through functional group interactions and reactive oxygen species (ROS) generation, leading to nucleic acid and protein leakage, impairing membrane integrity, and suppressing bacterial proliferation. In conclusion, CTAB‐PW 12 and Py‐PW 12 exert potent antibacterial effects via membrane disruption, offering promising applications in medicine, food packaging, and environmental protection.