Sponsored by Dublin Institute of Technology (DIT) and Enterprise Ireland (EI), the Centre for Research in Engineering Surface Technology (CREST) was set up, to boost and combine the Institute’s research activity in favour of the industrial and academic communities. The Centre offers services ranging from material surface characterisation and corrosion control to the development of coatings and Nano-materials for diverse industries.
THE BUSINESS NEED
CREST and DIT developed a light-activated antibacterial surface coating, which was licensed by Radical-Coatings, a scientific spin out company launched in 2010. Radical-Coatings, the technology transfer company for CREST, were working with a tile manufacturer VitrA Ireland to produce antibacterial coating for tiles to sell specifically into the healthcare and swimming pool markets.
The coating of the tiles contains titanium dioxide, which when exposed to UV light creates free radicals that can kill bacteria. However as Radical-Coating’s target market is hospitals and swimming pools UV light reacting tiles are not practical. Therefore CREST and Radical-Coating altered the technology to react to visible light.
In order to achieve third party validation and provide Radical-Coating with world class data to present to international markets, the tiles needed to be tested according to the ISO 27447 standard.
Radical-Coating wanted their product tested to the ISO 27447 Standard, which measures the antibacterial activity of UV induced titanium dioxide coating, however as the technology was altered to react with visible light, the method of testing had to be adapted.
They also wanted the coating tested against different bacterial strains. Keeping their target market in mind, Radical-Coating wanted to specifically test the coating against MRSA (Methicillin-resistant Staphylococcus Aureus) and Trichophyton rubrum (an Athlete’s Foot fungus). As there are several types of fungi that cause Athlete’s Foot, it was vital that airmid healthgroup‘s team selected the right ones, aligned with Radical-Coating’s project goals.
The amount of sample testing required resulted in the generation of hundreds of plates and so the time management, sample tracking and interpretation had to be accurate and controlled.
The airmid healthgroup team applied an open approach to the project, involving the client at all stages this ensured the results of the research were in line with their objectives.
The study investigated the antibacterial reactions of 4 types of semiconducting photocatalytic using MRSA and Trichophyton rubrum.
Stage 1: MRSA Testing
The ISO 27447 2009 test method for antibacterial activity of semiconducting photocatalytic materials was used as a guide during testing, although a number of deviations to this standard were agreed with the client in advance of testing commencement. After exposure to the MRSA strain the sample was incubated aerobically for 24 hours before serial dilutions were carried out. The Tile samples were incubated under two different light exposures.
Stage 2: Trichophyton rubrum Testing
Antifungal activity of semi-conducting photocatalytic materials is not within the scope of ISO 27447 although testing was conducted based on this standard. Pure cultures of Trichophyton rubrum were grown and allowed to sporulate over a period of 5 weeks. Serial dilutions were made and tested on the tiles. Incubation conditions identical to those carried out during MRSA testing were applied.
After completing the research, airmid healthgroup validated that the light-activated antibacterial surface coating technology is 99.9% efficient at killing MRSA, E. Coli and the Trichophyton rubrum fungus that causes Athlete’s Foot.
CREST, Radical-Coating and VitrA Ireland showcased the tiling product range at the first European Innovation Convention in Brussels in December 2011. The innovative and ground-breaking technology was one of only 50 projects selected from 450 entries to take part in the inaugural event.
As the airmid research was independent, CREST now use the report data in their presentations on the subject as it clearly demonstrates how effective the tiles are in killing these bacteria.
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