With the hazard of bacterial infections threatening public health and the emergence of multidrug-resistant bacteria, namely, superbugs, novel innovations for use against bacteria have been explored.
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Tungsten oxide (WO3) is a chemical compound containing the metal tungsten and oxygen and has gained remarkable attraction for its antibacterial properties. This could be a potentially innovative step towards solving antibiotic resistance, and incorporating nanotechnology for this application may advance medicine and healthcare globally. Here, we explore the use of tungsten oxide for antibacterial applications.
The threat to public health is complex, with many different pathogens which are a concern for morbidity and mortality.
Bacterial infections, for example, are a significant problem. Health statistics show approximately 48 million cases of pathogenic diseases are diagnosed annually. More specifically, bacterial infections are also an agent for 88,000 deaths per year in the United States. This illustrates the significance of bacterial strains on public health and the critical need for innovative research for quality disease treatment and prevention.
Additionally, the overuse of antibiotic treatment over recent years has decreased their level of efficacy against bacterial infections - resulting in the emergence of superbugs. These highly resistant bacterial strains are notoriously known for their resistance against antibiotic treatment, especially with the transference of resistant genes to other strains, furthering antibiotic resistance against bacteria.
Ultimately, this has led to the necessity of novel antibiotics to overcome the global public health concern against superbugs.
Current Antibacterial Research
Current research has illustrated the benefits of utilizing inorganic nanomaterials due to having a small size and large surface area, which enhances their high reactivity. Additionally, their suitability as an antibacterial agent enables inorganic nanomaterials to keep stable under harsh conditions, including high temperature and pressure.
Inorganic nanomaterials can be utilized for various biomedical applications in biocatalysis, cell imaging and drug delivery to use within tumor diagnosis and treatment.
Metal nanoparticles such as those incorporating silver and copper have illustrated strong germicidal activity; however, silver nanoparticles can be toxic to mammalian cells with their interactions with thiol groups of proteins within cells. In comparison, metal oxide nanoparticles have been a good candidate for use against bacteria due to low cost and reduced toxicity levels.
Tungsten Oxide Research for Antibacterial Applications
The antibacterial activity of tungsten has been explored by various researchers, such as incorporating tungsten oxide within nanodots, which was found to be more effective in killing germs than larger particles as these particles were more uniform ultra-small (1.1±0.3nm).
Tungsten oxide nanodots within the UV-vis spectrum illustrated strong absorption across the near-infrared range, making these innovative particles optimal for applications such as the imaging of tumors. The versatility of this antibacterial agent increases its research for various applications.
Specifically, the research into using tungsten oxide nanodots against bacteria has been shown to have positive results. Researchers have found that a 2-hour treatment of this antibacterial agent has illustrated high potential against germicidal activity against E.coli. A concentration of 100μg/mL was shown to decrease cell validity to 19.7%. The possibility of using this agent in a concentration-dependent manner could be a step towards possible novel antibiotic development.
This antibacterial efficacy against other bacterial species such as S. aureus was also found to be high with a 6-hour treatment with tungsten oxide nanodots enabling a maximum potential loss of viability of these bacteria species.
Bacterial impairment is enabled by the adherence of tungsten oxide to the surface of bacterial cells. The loss of cytoplasm within S. aureus was found to be the downfall of the interaction of this bacteria species with tungsten oxide. Additionally, images from transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have found severe injury of bacterial cells through membrane damage and effusion of cytoplasm. This illustrates that this interaction between tungsten oxide and bacteria may directly involve the membrane and result in its dysfunctionality.
The use of this antibacterial agent was found to be toxic for most of the bacteria strains studied without UV irradiation and can lead to complete E.coli sterilization within cultural media with extensive exposure.
Using tungsten oxide for antibacterial activity could be a potentially innovative method that may provide a solution for less effective antibiotics that may not be able to treat antibiotic-resistant strains. Incorporating nanotechnology within antibacterial use would be useful due to its nanoscale benefits. With tungsten oxide being a novel compound, resistance against bacteria would no longer be an issue.
Its promising results for concentration-dependent antibacterial activity against bacterial strains would require further research to translate this incorporation of tungsten oxide nanoparticles for commercial use as a medical product. Exploiting tungsten oxide for its antibacterial properties may solve many bacterial-related infections worldwide and help to reduce morbidity and mortality rates.
Continue reading: Disease Diagnosis with Magnetic Nanoparticles.
References and Further Reading
Duan, G., Chen, L., Jing, Z., De Luna, P., Wen, L., Zhang, L., Zhao, L., Xu, J., Li, Z., Yang, Z. and Zhou, R., (2018) Robust Antibacterial Activity of Tungsten Oxide (WO3-x) Nanodots. Available at: https://doi.org/10.1101/494260
Matharu, R., Ciric, L., Ren, G. and Edirisinghe, M., (2020) Comparative Study of the Antimicrobial Effects of Tungsten Nanoparticles and Tungsten Nanocomposite Fibres on Hospital Acquired Bacterial and Viral Pathogens. Nanomaterials, 10(6), p.1017. Available at: https://www.mdpi.com/2079-4991/10/6/1017
Popov, A., Zholobak, N., Balko, O., Balko, O., Shcherbakov, A., Popova, N., Ivanova, O., Baranchikov, A. and Ivanov, V., (2018) Photo-induced toxicity of tungsten oxide photochromic nanoparticles. Journal of Photochemistry and Photobiology B: Biology, 178, pp.395-403. Available at: https://www.sciencedirect.com/science/article/pii/S1011134417310448?via%3Dihub