Synthesis and Complete Antimicrobial Characterization of CEOBACTER, an Ag-Based Nanocomposite

Abstract

The antimicrobial activity of silver nanoparticles (AgNPs) is currently used as an alternative disinfectant with diverse applications, ranging from decontamination of aquatic environments to disinfection of medical devices and instrumentation. However, incorporation of AgNPs to the environment causes collateral damage that should be avoided. In this work, a novel Ag-based nanocomposite (CEOBACTER) was successfully synthetized. It showed excellent antimicrobial properties without the spread of AgNPs into the environment. The complete CEOBACTER antimicrobial characterization protocol is presented herein. It is straightforward and reproducible and could be considered for the systematic characterization of antimicrobial nanomaterials. CEOBACTER showed minimal bactericidal concentration of 3 μg/ml, bactericidal action time of 2 hours and re-use capacity of at least five times against E. coli cultures. The bactericidal mechanism is the release of Ag ions. CEOBACTER displays potent bactericidal properties, long lifetime, high stability and re-use capacity, and it does not dissolve in the solution. These characteristics point to its potential use as a bactericidal agent for decontamination of aqueous environments.

Effect of antimicrobial nanocomposites on Vibrio cholerae lifestyles: Pellicle biofilm, planktonic and surface-attached biofilm

“…In V. cholerae, in the presence of sub-lethal concentrations of AgNPs and ZnONPs, changes on the relative expression of outer membrane proteins such as OmpT and OmpU were reported [7]. In the present study, the antimicrobial properties of CEOBACTER (AgNP-doped zeolites, ZEO-AgNPs) [24,25], and the new nanocomposites ZEO-CuNPs, and ZEO-ZnNPs (copper and zinc nanoparticles-doped zeolites, respectively) were evaluated on three different lifestyles of Vibrio cholerae O1 biotype El Tor A1552: pellicle biofilm (PB), planktonic cells, and surface-attached biofilm (SB) [26]. We analyzed changes on gene expression of vpsR, vpsL, rbmA and bap1, genes involved in biofilm formation.…”

“…Silver, copper and zinc zeolite nanocomposites (ZEO-AgNPs, ZEO-CuNPs, and ZEO-ZnNPs) were synthesized following the methodology described in the patent application MX/a/2012/ 013218 and in previous work [24,25]. ZEO-AgNPs, ZEO-CuNPs, and ZEO-ZnNPs were characterized by X-ray diffraction (XRD, Philips X'Pert diffractometer-CuKα radiation), by scanning electron microscopy (SEM, JEOL JSM-5300 microscope) and by transmission electron microscopy (TEM, JEOL JEM-2010 with accelerating voltage of 200 kV).…”

“…The resulting nanocomposites, ZEO-AgNPs, ZEO-CuNPs, and ZEO-ZnNPs, were insoluble powders as observed in scanning electron microscopy (SEM) images (S1 Fig), consisting of spheroidal-shape grains with 25 μm of average diameter, formed by packing of needle-shaped mordenite crystals. X-ray diffraction (XRD) patterns exhibit good defined single phase mordenite-type zeolite structure with high crystallinity, where no reflections of the metallic silver, copper, or zinc were present as evidence of the absence of bulk-like particles [24,25,30]. To demonstrate the presence of the nanoparticles and to evaluate their size, AgNPs, CuNPs and ZnNPs were visualized by transmission electron microscopy (TEM) before and after 48h of culture media treatment, and no changes due to media and incubation time were detected (S2 Fig).…”

“…The Zeta-potential analysis showed the good quality of the nanocomposites before and after treatment, with an average value of -15.50 mV before treatment and -18.15mV after 48 hours of treatment (S1 Table). Due to the synthesis method, the advantage of these nanoparticles is that they do not detach from the crystalline zeolite structure, and more importantly, the crystalline structure allows liquid permeation and ions release, which carry out the antimicrobial effect [25]. The nanoparticles immobilization hinders their oxidation, degradation and agglomeration, favoring long-term antimicrobial activity, as well as preventing detachment.…”

Bismuth Nanoantibiotics Display Anticandidal Activity and Disrupt the Biofilm and Cell Morphology of the Emergent Pathogenic Yeast Candida auris

“…While numerous nanotechnology-based drugs (nanopharmaceuticals) are currently under preclinical and clinical development [ 30 , 31 ], many are now available for use in healthcare, such as vaccines and nanoantibiotics [ 32 , 33 , 34 ]. Nanomaterials display a wide range of inhibitory activities against a broad diversity of pathogens—including viruses, bacteria, fungi, and protozoa—and can even overcome their resistance to current antimicrobial drugs [ 35 , 36 , 37 , 38 , 39 ]. The use of antimicrobial nanomaterials (nanoantibiotics) is a novel approach to combat C. auris , due to the possibility of synthesizing cost-effective, potent disinfectants and treatments.…”