Starch-silver hybrid nanoparticles: A novel antimicrobial agent

Starch-silver hybrid nanoparticles were synthesized by a method combining nanoprecipitation and autoclaving. Starch nanoparticles (SNPs) were used as matrix and stabilising agent for the silver nanoparticles (AgNPs) by using native starches from different botanical sources. The hybrid Ag-SNPs were characterized in terms of size, charge, morphology and molecular structure. Quantitative analysis of Ag was also carried out. Spherical SNPs were obtained with all starches with sizes ranging from 82 to 90 nm and neutral charge (zeta potentials around −1 mV). HR-TEM micrographs demonstrated the presence of AgNPs of 5–10 nm. FTIR showed AgNPs encapsulation within the SNPs. The antimicrobial activity of the formulations was demonstrated against Escherichia coli and Staphylococcus aureus both in solid medium by the diffusion method and in microdilution method. Slightly higher antibacterial activity against E. coli was observed. Hybrid amaranth Ag-SNPs with 0.0005 M and 0.001 M of AgNO 3 showed log reductions of 4.21 and 4.35 respectively for S. aureus and bactericide effect against E.coli . Therefore, these hybrid NPs can be considered as sustainable promising nanomaterial with antimicrobial activity.