Interactions of Silver Nanoparticles with Pseudomonas putida Biofilms

Abstract

Silver nanoparticles (Ag NPs) may present a risk to the environment due to their expected toxicity and wide exposure. The interactions between Ag NPs and laboratory-grown Pseudomonas putida biofilms were investigated under a range of environmentally relevant conditions (pH 6 and 7.5; presence and absence of Suwannee River fulvic acid (SRFA)) over 4 days. In the absence of SRFA, there was extensive sloughing of the biofilm bacteria into suspension implying NP-bacterial interactions and potential effects on NP transport in the environment. In the presence of SRFA, sloughing of cells into suspension was reduced under some conditions and Ag NPs and their aggregates were observed and quantified on and in the bacterial cells in the biofilm. Viability of the cells in all cases appear unchanged by the presence of Ag NPs. Cell viability was independent of the concentration of NPs in solution, but sloughing rates varied substantially, sometimes in a dose-dependent manner. The results suggest that biofilms are impacted by Ag NPs when SRFA was not present, and that SRFA increases uptake and bioaccumulation of Ag NPs to biofilms, perhaps resulting in longer term effects, which need further investigation.

Biosynthesis, characterization, and evaluation of bioactivities of leaf extract-mediated biocompatible silver nanoparticles from an early tracheophyte,<em> Pteris tripartita</em> Sw.

“…The diameter of inhibitory zones ranged from 7.66 to 38.33 mm for AgNO 3 and AgNPs treatments, respectively (Table 3; Figure 5). The highest inhibitory effect was observed in treatment with 10 mg of AgNO 3 [67][68][69][70][71] In addition, biosynthesized Ag-NPs isolated from Citrullus colocynthis callus and Phyllanthus amarus extracts exhibited tremendous antibacterial activity against E. coli, P. aeruginosa, and P. vulgaris. 5,52 Both the concentrations of Ag-NPs (5 and 10 mg/mL) did not show any inhibitory activity against S. marcescens and positive strains like B. cereus 72 reported that Ag-NPs possessed antifungal properties because extracellular synthesis of NP helps trap metal ions on the cell surface and helps reduce ions in the presence of enzymes.…”

Silver Nanoparticles as Potential Antibacterial Agents

“…The results suggested that biofilms are impacted by the treatment with AgNPs. The nanoparticles analyzed in the study were of quite large dimensions (over 60 nm) [80]. One of the first reports on the antibiotic effect of AgNPs on P. aeruginosa and S. epidermidis, and their effect on biofilm formation, was produced by Kalishwaralal et al [81].…”

Nanomedicine opened new horizons for metal nanoparticles to treat multi-drug resistant organisms

“…The results suggested that biofilms are impacted by the treatment with NPs. The nanoparticles analyzed in the study were ofquite large dimensions (over 60 nm) (80). One of the first reports on the antibiotic effect of NPs on P. aeruginosa and S. epidermidis, and their effect on biofilm formation, was produced by Kalishwaralal et al2010., (81).…”