Titanium Dioxide: A Nontoxic Anti-Microbial with a Wide Range of Applications

Titanium Dioxide: A Nontoxic Anti-Microbial with a Wide Range of Applications
Titanium Dioxide: A Nontoxic Anti-Microbial with a Wide Range of Applications

With the advent of the coronavirus, people want to protect themselves and their families from infection. Titanium dioxide antimicrobial coating may be one of the solutions.

What Is Titanium Dioxide?

Titanium dioxide is metal oxide found in a natural mineral known as Ilmenite. When used as a pigment, it’s is called Titanium white and has three crystalline structures: brookite, rutile and anatase.

How Does Titanium Dioxide Anti-Microbial Coating Provide Sanitation?

Titanium dioxide is the active ingredient in antimicrobial coatings, and recent studies have shown its effectiveness in disabling surface microbes. When a titanium dioxide coating is exposed to UV light, it reduces water vapor in the air and produces free oxygen radicals that attack microbes like bacteria, viruses, mold spores and other organic compounds on surfaces. These coatings can be applied to most hard or soft fixed surfaces.

The University of Canterbury Study

In hospitals, viruses and bacteria are present in high concentrations; affordable and effective ways to disable surface microbes without increasing antibiotic resistance are needed.

Susan Krumdieck, a mechanical engineer at the University of Canterbury in New Zealand, has developed “an ultrasonic atomizer that makes a fine mist of a titanium dioxide precursor and sprays pulses of it into the chamber.” This mist increases the rate at which titania crystals grow.

The coating that Krumdieck developed is activated by visible light and has a surface area 100 times greater than titania coatings made with nanoparticles. That increases the presence and concentration of microbe-killing reactive oxygen.

Krumdieck tested the effectiveness of her coating by treating it with an E. coli culture and then exposing it to both UV and visible light. All bacteria in the UV light group were killed. In the visible light samples, 99 percent of microbes were destroyed. The coating was then tested on stainless steel faucets and door handles and on surfaces as large as dinner plates. Krumdieck believes this method will work on other metal surfaces as well as on glass.

Titanium Dioxide Uses in Woven and Non – Woven Textiles in the Medical Setting

Woven and non–woven textile materials act as a good platform for the spontaneous growth of microorganisms. The materials present in the natural fibers provide sustenance to microorganisms and therefore foster acceleration of their growth.  This growth in the textiles cause multiple problems such as foul odor, loss of strength in the textile, stains and most importantly, affect the wellbeing of the wearer. It is therefore paramount to utilize antimicrobials on textiles to protect the health of the wearer. Several antimicrobial agents have been used in textile applications [1].

Inorganic materials such as metal and metal oxides have garnered study due to their ability to withstand harsh processing [2,3]. Metal oxide such as Titanium Dioxide is now focused upon as it is stable under harsh process conditions but also safe to humans and animals [4].

Being mindful of general health conditions and because of the crucial need for antimicrobials during pandemics, most people are now focused on educating and protecting themselves against harmful microorganisms. It is therefore paramount for antimicrobial finished textiles to provide a level of protection to the wearer from organisms than it was to simply protect the garment from fiber degradation. [5]. The need for antimicrobial textiles is now mainstream with the rise in resistant strains of microorganisms including the COVID-19 virus.

A coating of titanium dioxide on fabrics enables improvement in antimicrobial properties [6]. Titanium dioxide is normally preferred over other titanium compounds due to its higher efficacy in preventing infectious microorganisms from growing.  In the specific instance of titanium dioxide treated textiles, no growth has been observed on fabric in numerous studies. [7] Treated woven fabrics exhibit better infectious organism reduction than their knitted counterpart, due to their construction.

Other Applications

Another recent application focused on cruise ships, hotels and airlines.  The coatings use the Titanium dioxide as active ingredient. After application, exposure of the treated surface to either artificial light or sunlight sets off a photocatalytic reaction in the coating that produces an ongoing cycle of surface and air purification.

Other Uses of Titanium Dioxide

Titanium dioxide is used to make a wide variety of products including sunscreen, toothpaste, tattoo pigment, ceramic glaze, paint, varnish, plastics, paper and food coloring.

The mineral is also used in fibers, printing inks, cosmetics and food. The ingredient can be found in glass ceramics, glass, metal patinas, electrical ceramics, electric conductors, catalysts and chemical intermediates.

FOOTNOTES

  1. Gao and R. Cranston, “Recent advances in antimicrobial treatments of textiles,” Textile Research Journal, vol. 78, no. 1, pp. 60–72, 2008.
  2. Fu, Z. Liu, Y. Liu et al., “Beaded cobalt oxide nanoparticles along carbon nanotubes: Towards more highly integrated electronic devices,” Advanced Materials, vol. 17, no. 2, pp. 217–221, 2005.
  3. Makhluf, R. Dror, Y. Nitzan, Y. Abramovich, R. Jelinek, and A. Gedanken, “Microwave-assisted synthesis of nanocrystalline MgO and its use as a bacteriocide,” Advanced Functional Materials, vol. 15, no. 10, pp. 1708–1715, 2005.
  4. K. Stoimenov, R. L. Klinger, G. L. Marchin, and K. J. Klabunde, “Metal oxide nanoparticles as bactericidal agents,” Langmuir, vol. 18, no. 17, pp. 6679–6686, 2002.
  5. Yadav, V. Prasad, A. A. Kathe et al., “Functional finishing in cotton fabrics using zinc oxide nanoparticles,” Bulletin of Materials Science, vol. 29, no. 6, pp. 641–645, 2006.
  6. J. Lee and S. H. Jeong, “Bacteriostasis and skin innoxiousness of nanosize silver colloids on textile fabrics,” Textile Research Journal, vol. 75, pp. 551–556, 2005.
  7. P. Chattopadhyay and B. H. Patel, “Improvement in physical and dyeing properties of natural fibres through pre-treatment with silver nanoparticles,” Indian Journal of Fibre and Textile Research, vol. 34, no. 4, pp. 368–373, 2009.
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