Antimicrobial Effects of Silver Nanoparticles against Bacterial Cells Adhered to Stainless Steel Surfaces

Abstract

Given the increasing number of antibiotic-resistant bacteria and the need to synthesize new antimicrobials, silver has attracted interest in the scientific community because of its recognized antimicrobial activity. This study aimed to evaluate the antimicrobial effects of silver nanoparticles (NP) obtained by a new method and tested at concentrations of 6 μg/ml and 60 μg/ml against the species Staphylococcus aureus, Listeria innocua, Salmonella Choleraesuis, Pseudomonas aeruginosa, Escherichia coli, and Bacillus cereus. The ability of these nanoparticles to remove or kill vegetative cells adhered to stainless steel surfaces was also evaluated. We observed that the NP obtained with the new method, concentrated silver nanoparticles (CNP), and silver nanoparticles with added sodium chloride (NPNaCl) had high antimicrobial activities (P < 0.05). We also verified that the most effective condition for the removal of P. aeruginosa cells on stainless steel coupons (10 by 10 mm) was immersion of the surfaces in CNP. The CNP treatment produced a 5-log reduction of the microbial population after 30 to 60 min of immersion. The CNP treatment also performed better than water and sodium carbonate, a compound commonly applied in clean-in-place procedures in the food industry, in removing adherent B. cereus cells from stainless steel cylinders. Therefore, these results suggest that NP synthesized by a new procedure may be used as antimicrobials in the food industry, for example, for the sanitization of utensils that come into contact with foods.

Nanoparticle Characterization of Traditional Homeopathically-Manufactured Silver (Argentum Metallicum) Medicines and Placebo Controls

“…We chose silver as the initial source material for HMs because of the growing research literature on the potential clinical utility of engineered silver nanoparticles for cancer and infectious disease treatment [20,[44][45][46][47][48][49][50]. Silver has good optical contrast properties for visualization in TEM, NTA, and other NP characterization technologies and a welldescribed UV-vis wavelength range, including red-shift of silver surface plasmon resonance peaks from interactions with silica [51,52] Prior infrared and Raman spectroscopy and photoluminescence studies on homeopathically-prepared medicines have shown that the material retains a spectroscopic [34,53,54] and photonic [28][29][30] "signature" of the original source material.…”

Biosynthesis of silver nanoparticles by Novosphingobium sp. THG-C3 and their antimicrobial potential

“…Nanotechnology is one of the most attractive areas of research in modern material science due to their potential applications in numerous fields, including mechanics, biomedical, energy science, catalysis, optoelectronics, magnetics sciences, and sensors (Araujo et al 2012, Sulaiman et al 2013. Metal nanoparticles (MNPs) pave significance attraction of researchers because of their unique properties such as increased catalytic activity due to morphologies with highly active facets as compared to bulk material (Ahmed et al 2015).…”

Enhancement of adaptive biological effects by nanotechnology preparation methods in homeopathic medicines

“…34,137e140 Nanoparticles can adsorb onto stainless steel container surfaces as well. 141,142 However, if a manufacturer uses traditional methods to make their higher potency remedies, borosilicate glassware e and hence, silica e will likely be involved during succussion steps. 5 In contrast with conventional bulk form materials, smaller nanoscale structures, including nano-silica, acquire unusual electromagnetic, magnetic, optical, electronic, and quantum mechanical properties.…”