Swift-kinetics driven RSM optimized, biocompatible AgNPs inhibit uropathogenic biofilms via AHL interference: mechanistic insights from Ag8-SdiA in-silico docking

Urinary Tract Infections remain a highly prevalent global health concern, with biofilm-forming, multidrug-resistant uropathogens such as Uropathogenic Escherichia coli ( UPEC ) and Enterobacter hormaechei posing significant therapeutic challenges. In this study, silver nanoparticles synthesized using Mussaenda philippica L. leaf extract were optimized through RSM, investigated for its rapid reaction kinetics, tested for application in quorum quenching and hence biofilm disruption against two uropathogens - UPEC and E. hormaechei . Mechanistic insights are gained by molecular docking of Ag8 nanocluster with SdiA receptor of AI-1 signals. Green synthesis was optimized using RSM, achieving high nanoparticles yield and activity under optimal conditions (pH 9, 45 °C, 1.4 mM AgNO₃, 1.125% extract). It is a pseudo-first-order behavior (k′ = 0.4463 min⁻¹, R² = 0.94) with a half-life of 1.55 min, indicating rapid, chemically driven Mp-AgNPs formation without lag phase. Long-term colloidal stability was observed, with unaltered SPR peaks over two months, attributed to effective phytochemical capping. Antibiofilm activity was evaluated using qualitative and quantitative assays. Mp-AgNPs inhibited biofilms by 69% in UPEC and 67.78% in E. hormaechei , and reduced EPS. Mp-AgNPs also suppressed AHLs production and cell surface hydrophobicity. Mechanistic investigation from molecular docking simulation revealed that Ag8 cluster bind within the hydrophobic cavity of SdiA regulators in both uropathogens via metal-acceptor co-ordination. This docking insights suggests that Ag8 interaction may disrupt SdiA function, providing a mechanistic basis for AgNPs mediated quorum sensing interference and biofilm inhibition. Finally, excellent biocompatibility with HaCaT cells represent Mp-AgNPs as a promising green nanotechnology-based approach to combat AMR/MDR in uropathogens.