This study is a framework proposal for understanding the antimicrobacterial effect of both α-Ag 2 WO 4 microcrystals (AWO) synthesized using a microwave hydrothermal (MH) method and α-Ag 2 WO 4 microcrystals with Ag metallic nanofilaments (AWO:Ag) obtained by irradiation employing an electron beam to combat against planktonic cells of methicillin-resistant Staphylococcus aureus (MRSA). These samples were characterized by X-ray diffraction (XRD), FT-Raman spectroscopy, ultraviolet visible (UV−vis) measurements, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and high resolution transmission electron microscopy (HRTEM). The results reveal that both AWO and AWO:Ag solutions have bacteriostatic and bactericidal effects, but the irradiated sample is more efficient; i.e., a 4-fold of the MRSA planktonic cells as compared to the nonirradiated sample was observed. In addition, first principles calculations were performed to obtain structural and electronic properties of AWO and metallic Ag, which provides strong quantitative support for an antimicrobacterial mechanism based on the enhancement of electron transfer processes between α-Ag 2 WO 4 and Ag nanoparticles.

In recent years, complex nanocomposites formed by Ag nanoparticles coupled to an α-Ag2WO4 semiconductor network have emerged as promising bactericides, where the semiconductor attracts bacterial agents and Ag nanoparticles neutralize them. However, the production rate of such materials has been limited to transmission electron microscope processing, making it difficult to cross the barrier from basic research to real applications. The interaction between pulsed laser radiation and α-Ag2WO4 has revealed a new processing alternative to scale up the production of the nanocomposite resulting in a 32-fold improvement of bactericidal performance, and at the same time obtaining a new class of spherical AgxWyOz nanoparticles.

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New, effective antimicrobial agents are constantly being evaluated for addressing the increased prevalence of bacterial and fungal infections and emerging drug resistance. In this study, α-Ag2WO4 microcrystals were prepared by controlled coprecipitation (90 °C for 10 min) in different solvents (e.g., water, an alcoholic solution, and an ammoniacal solution). From the X-ray diffraction results, the newly synthesized α-Ag2WO4 microcrystals are well-indexed to the orthorhombic structure. Two morphologies were seen by field-emission scanning electron microscopy: microrods in the alcoholic solution and flowerlike structures in water and the ammoniacal solution. The synthesized α-Ag2WO4 microcrystals exhibited antimicrobial activity against Candida albicans, Escherichia coli, and methicillin-resistant Staphylococcus aureus. In addition, the antibacterial performance of the α-Ag2WO4 samples as a function of their structural and morphological features was discussed.