Assessment of Size-Dependent Antimicrobial and Cytotoxic Properties of Silver Nanoparticles

Abstract

Nanoscale silver has been increasingly applied to commercial products for their antimicrobial function as antibiotics and disinfectants. In this work, the different sizes of silver nanoparticles (AgNPs) were studied not only inMethylobacterium spp. for their antimicrobial potential but also in human peripheral blood mononuclear cells (PBMCs) for their cytotoxicity in order to determine responses dependent on their particle size. Size controlled silver particles were prepared by chemical reduction of silver cations (Ag+) and then dispersed in water for their physicochemical characterization using transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential measurements. To ascertain antimicrobial response, water-soluble silver nanoparticles were mixed intoMethylobacterium spp. cultured for two days and the sample from the broth was spread on the agar plate for colony counting. 10 nm nanoparticles showed more antimicrobial activity than 100 nm particles at which concentrations were equivalently controlled. Increased cytotoxic effect of smaller silver nanoparticles was also observed in PBMCs cocultured with particles. Silver ions released from 10 nm particles might be correlated with upregulated antimicrobial and cytotoxic properties of AgNPs.

Antimicrobial dependence of silver nanoparticles on surface plasmon resonance bands against <em>Escherichia coli</em>

“…Further observations showed that smaller NPs have higher antimicrobial properties compared to larger NPs because of better contact with microbial cells and their tendency to release more Ag + ions that can easily interact with microbial cells compared to larger NPs 2,8,22,23,30,50–52. The observations contradict the results of previous research13,24 that triangular AgNPs were more effective against E. coli than spherical NPs.…”

“…Therefore, much painstaking work has, over the decades, sought to optimize several factors that affect the shapes and sizes of NPs. The most notable studies have centered on the effects of shapes and sizes on the antimicrobial nature of NPs 13,14,24,30–32. The debate is currently over whether antimicrobial properties of AgNPs depend on the shape or size of NPs.…”

Assessment of antibacterial activity of two different sizes of colloidal silver nanoparticle (cAgNPs) against Vibrio harveyi isolated from shrimp Litopenaeus vannamei

“…So that smaller sized AgNPs showed faster bactericidal activity. Similar results were reported by Jeong et al (2014). They demonstrated that 10 nm AgNPs possess higher and faster cytotoxic and antimicrobial effects compared to 100 nm sized particles against Human PBMCs and Methylobacterium spp., respectively.…”

Biocidal properties study of silver nanoparticles used for application in green housing

“…During the last decades, silver metal nanoparticles (MNPs) have spurred a lot of interest due to their conductive, optical [1], catalytic [2], and more particularly biocidal properties [3,4]. In fact, among noble metals, Ag MNPs possess the most efficient biocidal properties with a very broad bactericidal and fungicidal activity spectrum.…”