Hybrids of copper cysteamine nanosheets and silver nanocluster ensure superior bactericidal capability via enhanced photodynamic effect

Abstract

Abstract Over the past decades, bacterial infections resulting from the misuse of antibiotics have garnered significant attention. Among the alternative antibacterial strategies, photodynamic therapy (PDT) has emerged as a promising non-antibiotic approach. However, persistent bacterial biofilms, particularly those composed of gram-negative bacteria with their protective outer membranes, have exhibited remarkable resilience to PDT. To address this challenge, we have developed an antibacterial composite material, silver nanoparticles coated-copper cysteamine (Cu-Cy-PEG@AgNPs), which demonstrates remarkable antibacterial activity against both gram-positive and gram-negative bacteria. Specifically, under UV irradiation, Cu-Cy-PEG@AgNPs achieves a sterilization efficiency of approximately 100% at a low concentration of 25 µg/mL. The incorporation of silver nanoparticles significantly enhances the antibacterial performance of Cu-Cy, effectively eradicating persistent bacterial biofilm infections. Moreover, Cu-Cy-PEG@AgNPs exhibits excellent biocompatibility with L929 cells, indicating its potential for use in relevant applications to combat bacterial infections.

Keywords

• Copper cysteamine
• Antibacterial activity
• Silver nanoparticles
• Reactive oxygen species (ROS)