Studying Copper Nanoparticle-Induced Programmed Cell Death in Bacteria

Recently, concerns over multidrug-resistant pathogens and incurable infections have increased due to the overuse and misuse of antibiotics. Nanomaterials, such as metallic and metallic oxide nanoparticles, have gained popularity in the biomedical field as potential new strategies to combat multidrug-resistant pathogens. This study investigated the use of copper nanoparticles (CuNPs) as a bactericide against three common hospital-acquired opportunistic pathogens-Escherichia coli (E. coli), Acinetobacter baumannii (A. baumannii), and Staphylococcus aureus (S. aureus)-which are increasingly developing drug resistance. Detailed protocols are presented for synthesizing CuNPs of two sizes (20 nm and 60 nm) and evaluating their bactericidal efficacy through colony assays. The mechanisms of antimicrobial action underlying CuNPs were explored by assessing changes in reactive oxygen species production. Additionally, four modulators that inhibit human protein functions were applied to study the potential involvement of programmed cell death (PCD) pathways in bacterial killing. Through this approach, the potential emergence of copper-resistant strains is suggested, building on research into copper homeostasis proteins, including copper-dependent transcriptional regulators. These findings provide a comprehensive methodology for studying the bactericidal effects of CuNPs and their potential role in addressing antibiotic resistance.