<p>Nanotechnology is becoming critical in the treatment of antibiotic-resistant bacteria infections. Ciprofloxacin was repurposed in this research by conjugation to sodium dodecyl sulfate (SDS)-capped silver nanoparticles (Cip-SDS-AgNPs) to promote antimicrobial activity. Nano-conjugates were chemically reduced with sodium borohydride (NaBH₄) and stabilized by SDS; reduction of Ag⁺ to elemental silver formed a deep yellow colloid, which changed to a deep orange after loading with ciprofloxacin, which demonstrated successful incorporation. The evaluation of antibacterial activity was conducted against Gram-negative (<i>Pseudomonas aeruginosa</i>,<i> Escherichia coli</i>) and Gram-positive (<i>Staphylococcus aureus</i>,<i> Listeria monocytogenes</i>) resistant bacteria. Among all the formulations, Cip-SDS-AgNPs demonstrated better inhibition zones (<i>E. coli</i> 28&#xa0;mm; <i>P. aeruginosa</i> 25&#xa0;mm; <i>S. aureus</i> 32&#xa0;mm; <i>L. monocytogenes</i> 37&#xa0;mm) than SDS-AgNPs, unmodified AgNPs and free ciprofloxacin. UV-visible spectroscopy, FTIR and SEM were used to confirm the morphology, surface characterization, and stability of nanoparticle formulations. Cip-SDS-AgNPs also displayed the highest anti-biofilm activity (tube assay and tissue-culture plate method) and a strong antioxidant potential in DPPH assay (85% scavenging at 100 ugmL^-1), compared to SDS-AgNPs, and bare AgNPs. <i>P. aeruginosa</i> was found to be the most susceptible via MIC and MBC determination (MIC 25 ugmL^-1; MBC 50 ugmL^-1), demonstrating the enhanced potency of Cip-SDS-AgNPs against prominent clinical bacterial strains. The formulation demonstrates the potential as a biocompatible, non-toxic carrier of effective drug delivery and increased antimicrobial efficacy. This study provides a new approach of repurposing ciprofloxacin by conjugation with nanoparticles, which offers a dual-action system with increased anti-bacterial and anti-biofilm performance against resistant strains.</p> Graphical Abstract <p></p>