We herein report the green synthesis of highly monodispersed, water soluble, stable
and smaller sized dextrose reduced gelatin capped-silver nanoparticles (Ag-NPs) via
an eco-friendly, completely green method. The synthesis involves the use of silver
nitrate, gelatin, dextrose and water as the silver precursor, stabilizing agent, reducing
agent and solvent respectively. By varying the reaction time, the temporal evolution
of the growth, optical, antimicrobial and sensing properties of the as-synthesised
Ag-NPs were investigated. The nanoparticles were characterized using UV-vis absorption
spectroscopy, Fourier transform infra-red spectroscopy (FT-IR), X-ray diffraction
(XRD), transmission electron microscopy (TEM) and high resolution transmission electron
microscopy (HR-TEM). The absorption maxima of the as-synthesized materials at different
reaction time showed characteristic silver surface plasmon resonance (SPR) peak. The
as-synthesised Ag-NPs show better antibacterial efficacy than the antibiotics; ciproflaxin
and imipenem against Pseudomonas aeruginosa with minimum inhibition concentration
(MIC) of 6 μg/mL, and better efficacy than imipenem against Escherichia coli with
MIC of 10 μg/mL. The minimum bactericidal concentration (MBC) of the as-synthesised
Ag-NPs is 12.5 μg/mL. The sensitivity of the dextrose reduced gelatin-capped Ag-NPs
towards hydrogen peroxide indicated that the sensor has a very good sensitivity and
a linear response over wide concentration range of 10(-1)-10(-6)M H2O2.