Facile room-temperature synthesis of cetyltrimethylammonium bromide (CTAB) coated spherical silver nanoparticles and their surface-enhanced Raman scattering (SERS) and antibacterial applications

Abstract

Silver nanoparticles (AgNPs) are appealing for their low cost and highly effective sensing and antibacterial properties. Herein, we report a facile near-room-temperature synthesis of AgNPs capped with a cationic surfactant using a single-step recipe. The AgNPs were synthesized by reducing silver ions in a basic medium in the presence of cationic surfactant cetyltrimethyl ammonium bromide (CTAB). By varying the concentration of CTAB and sodium hydroxide NaOH, the concentration and yield of the AgNPs can be tuned. The essential experimental conditions supporting the high yield of AgNPs are the low concentration of CTAB and the high concentration of NaOH. Moreover, the in uence of aging on AgNPs were studied by observing the variation in their UV-Vis spectra. The AgNPs puri ed by centrifugation and redispersed in CTAB solution showed reliable shelf-life in both light and dark conditions. Furthermore, AgNPs coated with a cationic surfactant have shown excellent surfaceenhanced Raman scattering(SERS) based trace detection towards anionic dye, methyl orange (MO). The AgNPs have a detection limit of 10 -10 M. Finally, the AgNPs have also shown good antibacterial activity against gram-positive bacteria i.e. Enterococcus spps and Staphylococcus Aureus.