Photoresponsive CuS@polyaniline nanocomposites: An excellent synthetic bactericide against several multidrug-resistant pathogenic strains

Surface modifications can optimize the antibacterial properties of inorganic materials; however, their high-cost, lengthy synthesis, and limited efficacy remain challenges in combating antibiotic resistance. Herein, we employed a rapid and low-cost solvothermal synthesis technique, followed by in situ oxidative polymerization of aniline to develop polyaniline-coated copper sulfide nanocomposites (CuS@PANI NCs), utilizing CuS and PANI as reactants to achieve efficient alternative bactericides. The as-prepared CuS@PANI NCs were initially investigated for structural, morphological, optical, and other spectroscopic analyses, confirming the successful coating of PANI onto the CuS nanoparticles. The in vitro case-control studies demonstrate the exceptional bactericidal performance of the CuS@PANI NCs against both Gram-positive (S. aureus and S. pneumoniae) and Gram-negative (E. coli and P. aeruginosa) bacteria with higher efficacy under visible light exposure at a dose as low as 30 & mu;g ml-1, compared to the pure CuS (60 & mu;g ml-1) and standard antibiotic ciprofloxacin (15 & mu;g ml-1), respectively, as evidenced by the respective zone inhibition assays. Radical trapping experiments coupled with electron spin resonance (ESR) measurements confirm that the O2- and h+ stand as the primary active species in the system. Moreover, the obtained results from computational simulations (in silico) of the as-synthesized materials against selected proteins (& beta;-lactamaseE. Coli and DNA gyraseE. coli) are in good agreement with the in vitro antibacterial findings, providing consistent validation. This study provides compelling evidence supporting potential of the polymers@inorganic composite materials as a powerful tool to combat antibiotic resistance to reduce the risk of infectious diseases. Surface modifications can optimize the antibacterial properties of inorganic materials; however, their high-cost, lengthy synthesis, and limited efficacy remain challenges in combating antibiotic resistance.