pH effect on the synthesis of different size silver nanoparticles evaluated by DLS and their size-dependent antimicrobial activity

Abstract

This paper reports citrate-stabilized silver nanoparticles (AgNPs) synthesized by nitrate ion chemical reduction with sodium borohydride, at different pHs (2–9). The AgNPs synthesized by this method exhibited size distribution from 5 to 249 nm, depending on pH, as determined by dynamic light scattering, and morphology spherical, as determined by transmission electron microscopy. In pH range 3–7 occurred aggregation of the nanoparticles. The size distribution depending on pH was determined by dynamic light scattering. The zeta potential was determined, and the colloidal stability was correlated with nanoparticles aggregation at different pHs. The size-dependent antimicrobial activity was evaluated for two solutions, wherein both samples exhibited antimicrobial activity, although the smallest AgNPs without agglomeration have enhanced antimicrobial properties.

Green synthesized silver nanoparticles: Optimization, characterization, antimicrobial activity, and cytotoxicity study by hemolysis assay

“…In acidic media compared to a basic one, the particle size is anticipated to be greater as well ( Khalil et al, 2014 ). These pH influences in the size-effect can be seen in the colors, which range from colorless to yellow ( Gontijo et al, 2020 ). The ability of the reaction pH to alter the electrical charges of biomolecules, which may have an impact on their capacity for capping and stabilizing, as well as the subsequent growth of the nanoparticles, is one of its significant influences.…”

Green Synthesis of Silver Nanoparticles Using Hypericum perforatum L. Aqueous Extract with the Evaluation of Its Antibacterial Activity against Clinical and Food Pathogens

“…The dynamic light scattering technique was used to estimate the mean size, size distribution, and agglomeration potential of AgNPs [ 58 ]. Figure 1 b shows the size of the resulting AgNPs depending on the relative frequency number weight (%).…”

Investigation of Antimicrobial Activity and Biocompatibility of Biogenic Silver Nanoparticles Synthesized using Syzigyum cymosum Extract

“…Any change in pH can alter the double-layer properties that directly influence the ζ potential of the system, increasing the chances of flocculation or coagulation because nanoparticles are stable near the isoelectric point . Additionally, the ζ potential near −30 mV is good for physical stability of nanoparticles (Figure S1a and Table S1), and the stability of bAgNPs did not significantly change between pH 5 and 10. Hence, solution pH does not significantly influence the ζ potential values of bAgNPs .…”