TiO2 Nanoparticles from Baker��s Yeast: A Potent Antimicrobial

Abstract

Titanium dioxide (TiO2) is commonly applied in food industry, cosmetics and pharmaceuticals due to its photocatalytic activity, stability, optical and electronic properties and biocidal activity. TiO2 nanoparticles (NPs) can be synthesized by conventional chemical, physical and biological methods. In this study, TiO2 NPs were biosynthesized using Baker's yeast (Y-TiO2) and characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray analysis (EDX). Antimicrobial activity was studied using plate coating method with and without sunlight exposure. XRD pattern confirmed the formation of pure anatase TiO2 nanoparticles. The porous surface of yeast cells act as the site for Ti 3 + nucleation. According to EDX data, Ti (Atomic percentage of 20.89%), O (70.95%), P (5.78%) and N (2.38%) were the key elements in the sample. TEM imaging revealed that the nanoparticles were spherical with an average size of 6.7 ± 2.2 nm. The photocatalytic activity of TiO2 NPs was studied by monitoring the degradation of Methylene blue dye. Fifty percent of dye degradation was observed within 15 min of UV exposure. This study is the first report on antimicrobial study of yeastmediated TiO2 NPs synthesized using TiCl3. Antimicrobial activity of TiO2 nanoparticles was high against selected Gram positive bacteria and Candida albicans compared to Gram negative bacteria in the presence or absence of exposure to sunlight. The percentage reduction of colony forming units (CFU/mL) after exposure to Y-TiO2 NPs following 30 min of sunlight exposure significantly reduced S. aureus ATCC 25923 (77%), MRSA clinical isolate (97%) and C. albicans ATCC 10231 (95%) compared to the control due to the photocatalytic activity. The percentage reduction of CFU/mL for gram negative bacteria P. aeruginosa ATCC 27853, E. coli ATCC 25922 and A. baumannii clinical isolate were 58%, 46% and 50% respectively after exposure to sunlight. Y-TiO2 NPs showed antimicrobial activity in the absence of exposure to sunlight under room conditions. After 30 min of contact with Y-TiO2 NPs, percentage inhibition of S. aureus (20%), MRSA (25%), C. albicans (74%), P. aeruginosa (30%), E. coli (26 %) and A. baumannii (23%) were lower compared to sunlight exposure. Sunlight exposure has enhanced antimicrobial activity of TiO2 NPs. The outcomes indicate the significant physical properties and the impact of yeast-mediated TiO2 nanoparticles as a novel antimicrobial.

Green synthesized titanium dioxide nanoparticles and their future applications in biomedicine, agriculture and industry

“…The same situation was observed by Peiris et al (2018) with thermic treatments of TiO 2 NPs synthesized by Saccharomyces cerevisiae. In all cases an anatase crystalline phase of TiO 2 NPs was obtained (Peiris et al, 2018).…”

“…In their experiment, biosynthesis reaction performed using yeast or albumen has led to the formation of anatase-TiO 2 NPs while rutile-TiO 2 NPs were obtained using dandelion pollen, these results being unchanged at different temperatures from 250°C to 750°C (Bao et al, 2012). The same situation was observed by Peiris et al (2018) with thermic treatments of TiO 2 NPs synthesized by Saccharomyces cerevisiae. In all cases an anatase crystalline phase of TiO 2 NPs was obtained (Peiris et al, 2018).…”

“…In general, these studies reported the formation of NPs with a small size, up to 20 nm. Peiris et al (2018) reported TiO 2 NPs with a size between 3.6 nm and 12 nm while NPs synthesized by He et al (2011) were 10-12 nm in diameter. Jha et al (2009) reported slightly larger NPs with dimensions ranging from 8 nm to 20 nm.…”

“…The antibacterial activity of green synthesized TiO 2 NPs was so far assessed on different types of human pathogenic bacteria including the most common Escherichia coli and other gastrointestinal pathogens, but also the ones causing lung infectious diseases (Subhapriya and Gomathipriya, 2018;Bavanilatha et al, 2019;Ahmad et al, 2020;Ağçeli et al, 2020). When it comes to fungal species, the most targeted seems to be Candida albicans (Ağçeli et al, 2020;Peiris et al, 2018;Subhapriya and Gomathipriya, 2018;Sundrarajan et al, 2017), although some experiments tested the antifungal activity of TiO 2 NPs against some species of Aspergillus (Ağçeli et al, 2020;Ahmad et al, 2020;Sundrarajan et al, 2017) or Arthrographis cuboid (Ahmad et al, 2020). Using phytochemicals from Kniphofia foliosa plant, Bekele et al (2020) managed to obtain bio-TiO 2 NPs that were almost as effective as gentamicin, a commonly used antibiotic.…”

The Antibiofilm Effect of a Medical Device Containing TIAB on Microorganisms Associated with Surgical Site Infection

“…The antimicrobial activity is performed through the induction of the production of reactive oxygen species (ROS), which damage the cellular membrane and cause the peroxidation of proteins and lipids. Recently, Peiris et al showed that the antimicrobial activity of TiO 2 nanoparticles biosynthesized by using Backer’s yeast was greater versus Gram-positive bacteria and Candida albicans than versus Gram-negative ones [14]. Noble metals such as Ag are often used to modify oxide-based semiconductors for improving the antimicrobial activity [15].…”