Synergistic Effect of Bovine Serum Albumin–Gold Nanoclusters Against Antibiotic‐Resistant Bacterial Sustainability and Biofilm Fabrication

This study evaluated the antimicrobial and antibiofilm effects of bovine serum albumin–gold nanoclusters (BSA–GNCs) against planktonic and antibiotic‐resistant bacteria. BSA–GNCs were synthesized and characterized using UV spectrofluorimetry, Fourier transform infrared spectroscopy (FTIR), zeta sizing, scanning electron microscopy (SEM)–energy‐dispersive x‐ray (EDX), and transmission electron microscopy (TEM) analyses. Cytotoxicity was evaluated using the MTT assay. Antimicrobial and antibiofilm activities were assessed against four bacterial strains: Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa , and Enterococcus faecalis . A characteristic UV absorption peak at 500 nm, along with a visible color change, confirmed successful GNC formation. FTIR spectra showed prominent functional groups at 598.33, 1102.79, 1261.21, 1637.84, 2923.54, and 3430.76 cm −1 , and the mean hydrodynamic diameter measured 22.72 nm. BSA–GNC exposure induced moderate cytotoxicity in HaCaT cells at concentrations above 40 µg/µL. Treatment with 40 µg/µL BSA–GNCs significantly enhanced bacterial growth inhibition zones (KP: 28 ± 2.44 mm; SA: 27.5 ± 2.45 mm; PA: 31.5 ± 1.91 mm; EF: 29.75 ± 2.5 mm) after 24 h. TEM imaging of BSA–GNC‐treated bacteria revealed shrunken, disrupted cells with degenerated cytoplasm. Additionally, BSA–GNC treatment markedly reduced biofilm formation at both 24 and 48 h compared with untreated controls. These findings indicate that BSA–GNCs enhance reactive oxygen species (ROS) accumulation, leading to impaired bacterial growth and biofilm formations.