Water-based binary polyol process for the controllable synthesis of silver nanoparticles inhibiting human and foodborne pathogenic bacteria

Abstract

aThe polyol process is a widely used strategy for producing nanoparticles from various reducible metallic precursors; however, it requires a bulk polyol liquid reaction with additional protective agents at high temperatures. Here, we report a water-based binary polyol process using low concentrations of highmolecular-weight polyethylene glycol (100 000 g mol À1, 2 wt%) and ethylene glycol (5 wt%). The entangled conformation of the polyethylene glycol in water and the increased number of reducing sites by the ethylene glycol cooperatively contributed to the stability and effectiveness of reduction reaction and particle growth, producing uniformly sized silver nanoparticles (15.8 AE 2.2 nm) with no additional protective agents at a mild temperature of 80 C. The measurement of particle size throughout the reaction and the dependence of the optical density of a silver colloidal solution on the concentration of ethylene glycol revealed three stages of particle growth. The minimum inhibitory concentrations of the purified silver nanoparticles against four representative human and foodborne pathogenic bacteria-S.aureus, P. aeruginosa, S. enterica, and E. coli-were 4.7, 2.3, 2.3, and 1.2 mg mL À1, respectively.

Brown Cotton Fibers Self-Produce Ag Nanoparticles for Regenerating Their Antimicrobial Surfaces

“…As opposed to the two-step increase observed at 100 °C, an additional slow increase, which lasts for approximately 20 min, appears before the rapid increase at 80 °C, showing a three-step increase. A three-step increase in SPR intensity has been observed in other syntheses of Ag NPs in bulk solutions with reducing and stabilizing agents. − In those syntheses, the three-step SPR evolution has been associated with a mechanism for NP formation involving three stages: (1) nucleation and nuclei growth, (2) particle coalescence, and (3) Ostwald ripening. The particle coalescence at the second stage gives rise to the greatest rate of particle growth.…”

Extracellular probiotic lipase capped silver nanoparticles as highly efficient broad spectrum antimicrobial agents

“…10,12,13,21 Table S1 † shows the comparative MIC values of Ag NPs available in the literature against various microbial strains. [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] As can be seen from the table, majority of the literature reported MIC values of Ag NPs against both bacteria and fungi in the mg mL À1 range. There are only a very few articles reporting the MIC values in the ng mL À1 range, which are closer to our current ndings.…”

Thermosensitive textiles made from silver nanoparticle-filled brown cotton fibers

“…27 Polyol molecules have been popularly used to synthesize Ag NPs. 28 The dendritic structure of tannins helps to cage Ag ions and stabilize the interaction with Ag ions for the reduction reaction. 27,29 Following nucleation and nuclei growth by the addition of Ag atoms, Ag particles rapidly grow by particle coalescence.…”