Antibacterial and antibiofilm effect of silver and gold nanoparticles in Uropathogenic Escherichia coli

Nosocomial infections of the urinary tract are the most common nosocomial infections. Infectious diseases currently pose a life threatening due to the increasing phenomenon of infectious agent resistance. One of the factors known to cause resistance to broad-spectrum antimicrobials agent is the susceptibility to biofilm formation. The use of silver nanoparticles (NPs) is now regarded as one of the most promising strategies to target infections associated with biofilms. This study aims to determine the application of nanotechnology in the form of metal nanoparticles in targeting the formation of biofilms on infectious agents. The antibacterial and antibiofilm activity test was performed on a 96-well microtiter plate on uropathogenic Escherichia coli (UPEC) at concentrations of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 ppm. The results showed the addition of silver and gold nanoparticles at different concentrations affected and inhibited the growth of UPEC and prevented the formation of biofilms, as indicated by a decrease in the OD value. In conclusion, silver and gold nanoparticles have antibacterial and antibiofilm effects on UPEC.

Efficacy of silver and gold nanoparticles obtained from vermiwash: In vitro study on antimicrobial and antidiabetic activities

Emerging nanobiotechnology has provided innovative techniques to synthesize nanoparticles through biological methods to explore the potentialities of biological sources like phytoextracts, microbes, animal secretions and excretion. This research studies the potential of vermiwash to synthesize the silver and gold nanoparticles and evaluate its in vitro effect of antimicrobial and antidiabetic activities. The characterization of the nanoparticles was analyzed through various techniques. Ultraviolet (UV)-Visible spectroscopy showed the maximum absorption spectrum at 413 nm for silver and 541 nm for gold nanoparticles. Fourier transform infrared spectroscopy (FTIR) revealed the reducing agent involved in nanoparticles synthesis. Scanning electron microscope (SEM) images revealed the size of the silver and gold nanoparticles as 24 nm and 50 nm, respectively. Energy dispersive X-ray (EDAX) analysis revealed the elemental composition of the synthesized nanoparticles. X-ray diffraction (XRD) analysis confirmed the crystalline nature of the nanoparticles that displayed the preferential orientation of the crystals toward the (111) plane. Antimicrobial activity was assessed using the resazurin assay method. A minimum inhibitory concentration (MIC) of less than 7.8 µg was observed in Staphylococcus aureus and Klebsiella pneumoniae. In the antifungal activity, MIC at 250 µg was noted in Mucor sp. and Candida albicans. Antidiabetic activity was assessed by α-amylase and α-glucosidase inhibitory assay. IC50 of α-amylase and α-glucosidase activity of the silver nanoparticles was noted as 218 and 221 µg/mL, respectively. IC 50 value for the enzymatic assay dose-dependently confirmed the effect. Conclusively biosynthesized nanoparticles from vermiwash showed potential efficiency of antibacterial, antifungal and antidiabetic activities.

Plasmon-Modulated Excitation-Dependent Fluorescence and Antimicrobial Activities of Silver and Gold Nanoparticles Prepared with Eugenia unifloraL. extracts

Green synthesis using plant extract is a sustainable method to obtain silver and gold nanoparticles (Ag and AuNPs) and was employed in this work. The Eugenia uniflora L. fruits and leaves extracts were used in nanoparticles synthesis. The photoreduction process with a xenon lamp and pH control improved optical properties and nanoparticles stability. The UV-vis, TEM, FTIR, and Zeta potential of the prepared solutions were obtained. The fluorescence spectra of Ag and AuNPs were investigated at different excitation wavelengths, which showed two kinds of fluorescence peaks. The shorter wavelength peaks red-shift with the increasing excitation wavelength, which results from the electron interband transitions, and the longer fixed wavelength peaks due to the local field enhancement. Finally, the antimicrobial tests were performed with Gram-negative and Gram-positive bacteria and Candida albicans. The best results were obtained with EuAgNPs prepared with fruits extract, photoreduction, and pH 7.0 (with a mean of 95.12% ± 10.29% of inhibition).

Current Knowledge of Silver and Gold Nanoparticles in Laboratory Research—Application, Toxicity, Cellular Uptake

Silver and gold nanoparticles can be found in a range of household products related to almost every area of life, including patches, bandages, paints, sportswear, personal care products, food storage equipment, cosmetics, disinfectants, etc. Their confirmed ability to enter the organism through respiratory and digestive systems, skin, and crossing the blood–brain barrier raises questions of their potential effect on cell function. Therefore, this manuscript aimed to summarize recent reports concerning the influence of variables such as size, shape, concentration, type of coating, or incubation time, on effects of gold and silver nanoparticles on cultured cell lines. Due to the increasingly common use of AgNP and AuNP in multiple branches of the industry, further studies on the effects of nanoparticles on different types of cells and the general natural environment are needed to enable their long-term use. However, some environmentally friendly solutions to chemically synthesized nanoparticles are also investigated, such as plant-based synthesis methods.