Enhanced Antibacterial Efficacy: Rapid Analysis of Silver-Decorated Azithromycin-Infused Soluplus® Nanoparticles Against E. coli and S. epidermidis Biofilms

Abstract

The escalating threat of antibiotic-resistant bacterial biofilms necessitates innovative antimicrobial strategies. This study introduces silver-decorated, azithromycin- Soluplus® nanoparticles (Ag-AZI-Sol NPs), synthesized via a controlled emulsion diffusion method to ensure sustained release of antimicrobial silver ions for over six hours—a critical factor for continuous antibacterial efficacy. The efficacy of these nanoparticles was evaluated against biofilms formed by Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis), pathogens that cause hospital-acquired infections. Concentrations of 5 and 10 µg/mL, Ag-AZI-Sol NPs induced significant morphological changes within biofilms, disrupting the bacterial extracellular matrix as observed using scanning electron microscopy (SEM). This disruption peaked between two and six hours, coinciding with damage to bacterial cells by silver ions. Antibacterial assay measurements and optical density (OD) confirmed a significant reduction in growth rate among Ag-AZI-Sol NPs treated bacteria compared with controls. Electrochemical analysis using laser-induced graphene (LIG) and chronoamperometry revealed a decline in current, indicating an effective antibacterial effect. This innovative biosensing technique makes use of the high conductivity and huge surface area of LIG to detect changes in bacterial activity quickly and sensitively. Our findings highlight the potent microbicidal properties of Ag-AZI-Sol NPs and suggest diverse applications from food processing to medical device coatings.