Completely green synthesis of dextrose reduced silver nanoparticles, its antimicrobial and sensing properties

• Completely green synthesis of Ag-NPs using dextrose as reducing agent is reported.
• The as-synthesised Ag-NPs showed better efficacy than the antibiotics; ciproflaxin and imipenem.
• The minimum inhibition concentration (MIC) was 6 μg/mL against Pseudomonas aeruginosa.
• The minimum bactericidal concentration of the as-synthesised Ag-NPs was 12.5 μg/mL.
• The Ag-NPs were very sensitive towards H2O2 upto a concentration of 10−6 M.

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.