Synergistic Antimicrobial Action of Green-synthesized Silver Nanoparticles Functionalized with Cetylpyridinium Chloride

Abstract

Silver nanoparticles (AgNPs) has a broad-spectrum of antimicrobial properties. The synergistic effect could add therapeutic potential because AgNPs are functionalized with cetylpyridinium chloride (CPC), a member of quaternary ammonium groups. The present study focuses on the synthesis, characterization and antibacterial activity of silver CPC-coated silver nanoparticles (CPC AgNPs) concerning the design of antibacterial agents on common oral and opportunistic pathogens. The plant-based silver nanoparticles were synthesized by green synthesis to obtain CPC-AgNPs and then the CPC was coated at different ratios (1:1 to 1:5). UV Visible spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR) were employed to establish nanoparticle formation and the interaction of functional groups with the formulations. The antimicrobial effect was evaluated by applying the agar well method against Candida albicans, Lactobacillus sp., Staphylococcus aureus and Streptococcus mutans. Based on the FTIR analysis, FTIR demonstrated the presence of functional groups like hydroxyl, amine and aromatic functional groups that had an active role in the stabilization of nanoparticles and their interaction with CPC. UV–Visible spectroscopy showed a characteristic SPR peak around 350–370 nm, with increased absorbance over time, confirming nanoparticle formation and stability, particularly after 32 hours. CPC-AgNPs exhibited an increased antimicrobial effect over CPC in general and against C. albicans and S. aureus in particular. The 1:5 proportions showed the greatest area of inhibition (25 mm against C. albicans and 21 mm against S. aureus) which means that it was dose dependent. The CPC-AgNPs formulation was found to have synergistic, concentration related antimicrobial action. CPC-conjugated AgNPs afforded efficient and stable antimicrobial active components. These results favour the use of CPC-AgNPs in oral care, wound healing and infection control processes and justify further research in terms of cytotoxicity and inhibition of biofilm.