Cellulose nanofibrils improve dispersibility and stability of silver nanoparticles and induce production of bacterial extracellular polysaccharides

Abstract

Many polymer-stabilized silver nanoparticles (AgNPs) with enhanced antibacterial properties have been synthesized, but very little is known about the fate of these materials and their interactions with microbes in physiological solutions. In this study, we evaluated the role of cellulose nanofibrils (CNFs) in stabilizing AgNPs (CNF-AgNPs) in a bacterial growth medium, determined the antibacterial properties of CNF-AgNPs and assessed the CNF and CNF-AgNP interactions with bacteria. The attachment of AgNPs to CNFs significantly improved the stability and dispersibility of AgNPs in the bacterial growth medium compared to colloidal AgNPs. The CNF-AgNPs exerted a concentration-dependent growth-inhibitory effect on E. coli. An extracellular polysaccharide (EPS)-like structure was formed around the E. coli bacterium when incubated with a sub-lethal CNF-AgNP concentration, which led to the clustering of neighboring bacteria. No EPS-like structure was observed around the bacterium incubated with high concentration of CNF-AgNPs. Overall, this study demonstrated that CNFs significantly improved the stability and dispersibility of AgNPs in physiological medium, validated the antimicrobial potential of CNF-AgNPs, and provided an insight into the physio-chemical interactions between bacteria and CNF-AgNPs in a physiological growth medium.

Wood‐Based Nanotechnologies toward Sustainability

“…Silver nanoparticles (Ag NPs), known for their antibacterial properties, are prone to aggregate in physiological solutions, and therefore are limited in performance. Stabilizing the as‐synthesized Ag NPs with surface carboxylated CNF has been reported, showing that Ag NPs remain uniformly dispersed on the CNF surface after incubating in Lysogeny broth (LB) media at 37 °C for 18 h, without signs of aggregation (Figure g,h) . The CNF‐stabilized Ag NPs showed 40% cell viability and 3log decrease in bacterial counts by measure of the colony‐forming unit value.…”

“…Owing to its biodegradable and renewable characteristics, along with the high specific surface area and versatile surface chemistry, nanocellulose has been widely applied in wastewater treatment. The applications of nanocellulose in wastewater treatment generally include absorption/adsorption, catalytic degradation, and antibacterial ( Figure ), and the specific applications span from oil contaminant cleanup, heavy metals' adsorption, organic pollutant removal, as well as antibacterial . The detailed applications of nanocellulose in wastewater treatments have been recently reviewed, and therefore will only be briefly outlined here.…”

“…i) Fluorescence microscopy image of bacteria in the 150 × 10 −6 m CNF–Ag NPs for 18 h at 37 °C. g–i) Reproduced with permission . Copyright 2014, the Royal Society of Chemistry.…”

Synthesis of Cellulose Nanofibril Bound Silver Nanoprism for Surface Enhanced Raman Scattering

“…With added AgNO 3 , Ag + could bind with COO − by replacing Na + , as previously confirmed. 64 At lower CNF concentrations, both bound and free Ag + could be rapidly reduced by NaBH 4 , while free Ag atoms could nucleate with other free and bound Ag and grow quickly into small uniform AgNSs (Supporting Information, Scheme S1). At higher CNF concentrations with COO − in excess, most Ag + would bind with the CNF surface COO − and reduce to zero valence Ag atoms while still being attached to the CNF surfaces.…”

Nanocrystalline Cellulose-Assisted Generation of Silver Nanoparticles for Nonenzymatic Glucose Detection and Antibacterial Agent

“…(3) NCC has abundant hydroxyl groups as well as the charged surface, making it stable in water. 2 Due to these privileged physicochemical properties, NCC has attracted tremendous 3 interest from both scientific and industrial communities, and showed great potential in a variety of applications, including drug delivery, bioimaging, tissue engineering, [9][10][11][12][13][14][15][16][17] reinforcement of functional materials, [18][19][20][21] fabrication of structural color materials, [22][23][24][25][26][27] and so forth. 8,[28][29][30] NCC has also been proposed as a bio-derived matrix for the fabrication of various nanoparticles, such as silver, gold, platinum and palladium nanoparticles in a facile method.…”