Synthesis, antibacterial, cytotoxicity and sensing properties of starch-capped silver nanoparticles

In this study, we report the antibacterial, cytotoxicity and sensing properties of dextrose reduced starch-capped silver nanoparticles (Ag-NPs) synthesized via a completely green method. The synthesis involved the use of water, starch, and dextrose as the solvent, the stabilizing and the reducing agents respectively. Silver nitrate was used as the silver precursor without the use of any accelerator. The as-synthesised Ag-NPs were characterized with UV-vis absorption spectroscopy, Fourier transform infra-red spectroscopy (FTIR), Raman spectroscopy, X-Ray diffraction analysis (XRD) and high resolution transmission electron microscopy (HR-TEM). All the as-synthesised Ag-NPs showed good antibacterial activities against Escherichia coli and two strains of Pseudomonas aeruginosa, which are antibiotic sensitive and resistant bacteria. The study also indicated that the time of reaction did not have any significant effect on the antibacterial activity of the Ag-NPs synthesized despite the different particle sizes of the as-synthesised Ag-NPs. The cytotoxicity evaluation on human THP-1 monocyte cell line indicated that the as-synthesised Ag-NPs are less toxic than AgNO₃ at lower concentrations (2 μg/ml). Furthermore, the as-synthesised Ag-NPs were found to be very useful for colorimetric detection of hydrogen peroxide (H₂O₂) at lower concentration up to 10^-10 M with a linear regression coefficient value of 0.8822