Bacteriostatic study of Kanamycin synergistic Cu₂O/CuO composites targeting the bacterial cell wall

With the emergence of drug-resistant bacteria, the medical value of bacteriostatic agents represented by traditional antibiotics is gradually decreasing, so there is an urgent need to develo novel antimicrobials to solve the problems of bacterial drug resistance and improve the efficacy of antibiotics. In this paper, we prepared cuprous oxide nanoparticles (Cu₂O/CuO) from [Cu(NO₃)₂·3H₂O] and N₂H₄·H₂O, and then loaded kanamycin sulfate onto the cuprous oxide nanoparticles by the impregnation method. Finally, kanamycin sulfate (Kanamycin) was loaded onto the cuprous oxide nanocomposites by the "impregnation method" to obtain Kanamycin-coordinated Cu₂O/CuO (Cu₂O/CuO-Kanamycin) nanocomposites, and theMorphological structure, elemental content and bonding mode of the Cu₂O/CuO-Kanamycin composites were systematically characterised. Gram-negative Escherichia coli (E. coli), Gram-positive Staphylococcus aureus (S. aureus) and Kanamycin-resistant Salmonella (D-Salm) were used as model organisms to study the bacterial inhibition efficiency of Cu₂O/CuO-Kanamycin composites and their mechanism of action. The characterisation results showed that the prepared solid cubic Cu₂O/CuO structure, which is relatively stable due to the small contact area with air, can be mutually attracted and ligated with the —OH group of kanamycin. The inhibitory activities showed that the Cu₂O/CuO kanamycin complexes exhibited more than 99% inhibition of E. coli, S. aureus and D-Salm within 20 min at a concentration of 50 µg/ml, with a higher susceptibility to E. coli. The mechanism of bacterial inhibition showed that the composites killed the bacteria mainly by disrupting the structure of the bacterial cell wall. This study not only enhances the medicinal value of traditional antibiotics and significantly improves the antimicrobial performance against drug-resistant bacteria, but also provides a broad scientific basis for the fields of medical materials and environmental hygiene.