Antipyrine cationic surfactants capping silver nanoparticles as potent antimicrobial agents against pathogenic bacteria and fungi

Abstract Development of effective anti-microbial agents has been hindered by the emergence of bacterial strains with multi-drug resistance. In this article, we report an efficient synthesis of silver nanoparticle (AgNP) by capping with a synthetic cationic surfactants-based antipyrine. The synthesized antipyrine cationic surfactants were characterized by FT-IR and 1 H NMR and their AgNPs were also delineated by TEM, DLS and UV–vis techniques. These AgNPs-capped cationic surfactants have average particle size of ~ 15–30 nm. These surfactants could self-assemble to form micelles in an aqueous medium and the critical micelle concentration (CMC) values as well as the surface parameters were determined at 20, 40 and 60 °C. The synthesized antipyrine cationic surfactants and their AgNPs were tested against growth of both Gram positive ( Bacillus subtilis and Staphyl . aureus ) and Gram negative ( Pseudomonas aeruginosa and E . coli .) bacterial strains as well as fungi ( Candida albicans and Aspergillus niger ). It was found that the AgNPs significantly enhanced the antimicrobial activities of the synthesized antipyrine cationic surfactants. A strong structure-activity relationship was observed as a function of AgNPs functionality; providing guidance to activity prediction and rational design of effective antimicrobial nanoparticles. We propose that the antipyrine cationic surfactants-capped AgNPs can have potential bio-medical application against pathogenic bacteria.