Antibacterial Efficiency Of Green-Synthesized Rgo-Ag@PANI Nanocomposites For Water Disinfection Against Gram-Negative Bacteria

Abstract

The increasing prevalence of waterborne pathogens poses a significant threat to public health and necessitates the development of efficient, sustainable disinfection technologies. In this study, a novel rGO–Ag@PANI nanocomposite was green-synthesized using flower extract as a reducing agent, and its antibacterial efficacy was evaluated against E. coli and Pseudomonas. The nanocomposite was structurally characterized using UV–Vis, XRD, FTIR, and SEM, confirming the successful integration of rGO, Ag NPs, and PANI. Antibacterial performance was assessed via agar well diffusion, MIC, and bacteriostatic rate (BR%) analyses. Results demonstrated a strong dose-dependent antimicrobial response, with rGO–Ag@PANI showing maximum inhibition zones of 27.0 mm (Pseudomonas) and 23.0 mm (E. coli) at 300 µg/mL, individual components. The composite exhibited low MIC values (3.125 µg/mL for E. coli and 6.25 µg/mL for Pseudomonas), and high bacteriostatic rates (95.0% and 92.5%, respectively), indicating synergistic effects from its constituents. The enhanced antibacterial activity is primarily attributed to the generation of Reactive Oxygen Species (ROS) including hydroxyl radicals (•OH), hydrogen peroxide (H₂O₂), through interactions among Ag NPs, rGO, and PANI, leading to oxidative stress, membrane disruption, and bacterial death.  This study highlights the potential of rGO–Ag@PANI as an eco-friendly, efficient antibacterial agent for next-generation water disinfection systems.