Copper Sulfide Embedded Conjugated Polymer Nanohybrids as an Antibacterial and Antibiofilm Agent against Drug Resistant Bacteria

As antimicrobial resistance (AMR) continues to rise globally, there is an increasing need for antibacterial agents, and polymer nanostructures are emerging as promising candidates. In this work, we report conjugated polymer-based nanohybrids that exhibit broad-spectrum efficacy against pathogenic Gram-positive and Gram-negative microorganisms, inhibiting both microbial growth and biofilm formation. Specifically, antimicrobial nanohybrids composed of CuS nanoparticles and polyaniline (PANI) nanosheets demonstrate pronounced activity under 365 nm UV irradiation, achieving up to 70% bacterial removal at concentrations in the microgram-per-milliliter range. The CuS/PANI nanohybrids (NHs) displayed photoinduced antimicrobial activity both in suspension and as thin films deposited on glass substrates. The CuS/PANI exhibited significant zones of 13 ± 2.01 mm and 10.5 ± 0.70 mm against Staphylococcus aureus and Escherichia coli, respectively, as observed by agar well assay. At an MIC50 of 500 μg/mL, a reduction in biofilm biomass by 58.72% against S. aureus and 51.03% against E. coli was observed, indicating effective prevention of bacterial adherence and significant DNA and protein leakage (12.3–7.25 μg/mL) (12.6–8 μg/mL), respectively. The antimicrobial effect is attributed to membrane damage, ultimately leading to bacterial death and suppression of biofilm formation. The combination of biological safety at effective antimicrobial concentrations, broad-spectrum antibacterial performance, and strong inhibition of biofilm formation highlights the potential of the polymer-based NHs reported herein as promising candidates for therapeutic applications. The photoactivated CuS/PANI nanohybrid demonstrated potent antimicrobial activity, positioning them as a promising approach for combating bacterial infections.