Zinc Oxide Nanocomposite-Based Sonosensitizer for Broad-Spectrum Antimicrobial Applications

In recent years, the abuse of antibiotics has led to the emergence of numerous drug-resistant bacteria. Given that single antimicrobial materials can hardly achieve satisfactory inhibition against pathogenic bacteria, it is urgent to develop composite antimicrobial materials and strategies. In this work, inorganic piezoelectric ZnO nanoparticles were used as the core, modified to improve hydrophilicity, coated with polyethylene glycol (PEG), and then conjugated with the sonosensitizer chlorin e6 (Ce6) via amide bonds to form ZnO@PEG@Ce6 (ZGC) nanocomposites. The nanocomposites were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), cavitation intensity, absorbance, band gap, zeta potential, and particle size analysis. ZGC exhibits an octahedral structure with a uniform particle size distribution, and FTIR verified the stable chemical linkage among components. Synergy between ZnO piezoelectricity and Ce6 sonosensitivity greatly enhances ROS generation and results in superior sonodynamic antimicrobial activity. Gram-negative bacterium Pseudomonas aeruginosa, Gram-positive bacterium Staphylococcus aureus, and Candida albicans were selected as experimental subjects to study the antimicrobial activity and mechanism of the composite material ZGC. The experiment showed that under the action of ultrasound, the inhibition rates of ZGC against P. aeruginosa, S. aureus, and C. albicans were 58.7%, 68.29%, and 94.55%, respectively, which overcomes the disadvantage of the narrow antimicrobial spectrum of traditional sonosensitizers. Scanning Electron Microscope (SEM) images revealed that the synergistic effect of ZGC and ultrasound destroyed the surface structure of pathogenic strains, allowing reactive oxygen species to penetrate and damage the pathogens. ZGC-mediated sonodynamic therapy shows promising applications in chronic infected wound healing and implant-related infections, enabling efficient elimination of drug-resistant bacteria and precise antimicrobial treatment. This study provides insights and theoretical support for the development of broad-spectrum and highly efficient sonodynamic antimicrobial therapy.