The Antimicrobial Activity of Silver & Silver Iodide Nanoparticles Synthesized Via Chemical Reduction Method

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Saeed M. Feyadh, Asma H. Mohammed


Background: Nanotechnology is a new type of technology that has resulted in significant progress in a variety of disciplines. Nanoparticles (NPs) are extremely valuable in the field of biotechnology due to their unique properties and applications. Silver nanoparticles (AgNPs) have become one of the most investigated and explored nanotechnology-derived nanostructures in recent years, owing to the fact that nanosilver-based materials have proven to have interesting, challenging, and promising properties suitable for a variety of biomedical applications. Halogens are effective antibacterial agents; a combination of heavy metal compounds and halogens might be devised to increase antimicrobial activity. The purpose behind employing a low solubility chemical (AgI) as the shell is to prevent Ag from diffusing into the water and thereby poisoning it.

Objectives: To create AgNPs and AgI NPs using a chemical reduction approach. Examining the characteristics of the nanoparticles created and investigating the antibiological activity of the synthetized nanoparticles against a variety of harmful bacteria, including Gram-positive and Gram-negative bacteria, as well as antifungal activities.

Methods: A chemical reduction method was used for the synthesis of silver nanoparticles (AgNPs) and silver iodide nanoparticles (AgI NPs). Various techniques are used to investigate the optical and structural properties of product AgNPs and AgI NPs and determination of different parameters. Included UV–vis absorption, Photoluminescence (PL) spectra, X-ray diffraction (XRD), Field emission scanning electron microscope (FE-SEM), Transmission electron microscope (TEM) and Dynamic light scattering (DLS).  

Results: The presence of a plasmon peak was revealed by the optical data at 433 and 425 nm for AgNPs and AgI NPs respectively. At room temperature, the optical bandgap for AgNPs was found to be 2.94eV and 2.78eV for AgI NPs. Through XRD technique, the crystalline structure and the phase of the AgNPs and AgI NPs are identified. SEM results show that synthesized AgNPs and AgI NPs agglomerate and aggregate. According to TEM analysis, AgNPs and AgI NPs have a spherical shape with a Gaussian particle size distribution, with an average particle size of around 14 nm for AgNPs and 20 nm for AgI NPs. The data revealed an impact antibacterial activity of synthesized AgNPs and AgI NPs against both gram-positive and gram-negative bacterial strains. The prominent antimicrobial capability was for AgI NPs as well as being more effective against gram-negative bacteria.

Conclusions: The current study found that uniform and well-dispersed silver nanoparticles and silver iodide nanoparticles could be successfully produced and analyzed utilizing structural and optical methods employing a simple chemical precipitation approach. Their antibacterial properties have also been tested against a variety of common diseases. The average size of these precipitated nanostructures and they were spherical shape confirmed by UV-Vis, Pl spectra, XRD, FE-SEM, TEM, DLS and zeta potential analyses. Silver nanoparticles showed significant antibacterial activity against the selected Gram-negative and Gram-positive bacteria. The AgI NPs had a strong antibacterial capability against all of the microorganisms studied more than AgNPs in this study. As a result, the iodide enhanced antibacterial activity of the silver in combination of silver compounds and halogens. Also, there is no toxicity associated with the use of AgI NPs in various domains. It's worth noting that the AgI NPs examined are more efficient against gram-negative bacteria than they are against gram-positive bacteria. As a result, AgI NPs could be a promising candidate for development as an antibacterial agent against multidrug-resistant bacteria.

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