Bacteria meet their match in antibacterial coatings
Professor Jyrki Mäkelä is based in the Department of Physics at TUT. He uses the Liquid Flame Spray (LFS) method developed at TUT to manufacture aerosol-based antibacterial nanomaterials.
The hardiest germs can linger for days on door handles, taps, kitchen countertops and other surfaces that can easily become a breeding ground for harmful bacteria. Advanced coatings can turn these household surfaces into inhospitable environments for bacterial growth.
Bacteria are found everywhere, including our entire body. They can travel through the air or hitch a ride on dust particles. They do not grow under dry conditions but can survive them ― some for minutes, others for hours or even days. And as soon as the surface gets wet, they start multiplying.
The proliferation of bacteria poses a clear health risk, especially in hospitals.
Thin antibacterial surfaces
“Bacteria cannot cling to antibacterial surfaces or soon lose their grip if they try. Antibacterial coatings can be made, among others, from silver, titanium dioxide, zinc dioxide, copper dioxide or cerium dioxide. Their catalytic properties repel bacteria,” says Professor Jyrki Mäkelä from the Department of Physics at TUT.
Professor Mäkelä, Professor Martti Toivakka from Åbo Akademi University, Professor David Cameron from Lappeenranta University of Technology, and Adjunct Professor Erkki Eerola from the University of Turku and their respective research groups are participating in a project that aims at developing ultra-thin, nanostructured, large-area antibacterial surfaces. The project is funded by the Academy of Finland.
“Door handles and taps are usually the most bacteria-laden surfaces in hospitals and public spaces. It would be a massive step forward in preventing the spread of infections, if antibacterial coatings were habitually applied to these critical control points,” Mäkelä says.
A further goal of the project is to develop porous paper- and nanocellulose-based materials for antibacterial filters. They could be used to purify water in developing countries.
Nanocoatings fight off bacteria
The four-year nLABS (Nanostructured Large-area Antibacterial Surfaces) project was launched in an effort to better understand how different bacteria respond to nanostructured metal and metal oxide surfaces. The aim of the project is to develop sustainable ways to effectively inhibit bacterial growth.
The project started in September 2014 and will continue until 2018. The partners have secured some 1.5 million euros of funding from the Academy of Finland. The project involves Professor Martti Toivakka from Åbo Akademi University, Professor David Cameron from Lappeenranta University of Technology, Adjunct Professor Erkki Eerola from the University of Turku and Professor Jyrki Mäkelä from Tampere University of Technology and their research groups.
Cost savings and fewer raw materials
“We’re using two methods to produce nanocoatings for antibacterial surfaces. The first one is the aerosol-based Liquid Flame Spray (LFS) method developed at TUT in which antibacterial nanograins are deposited on a substrate. The second one is the Atomic Layer Deposition (ALD) method, which was invented in Finland and has been adapted for roll-to-roll production by researchers at Lappeenranta University of Technology. ALD coatings improve the adhesion of nanograins on a substrate,” Mäkelä describes.
The combination of the two methods provides a cost-effective and affordable way to manufacture antibacterial surfaces.
According to Mäkelä, nanoparticles are a sustainable alternative to larger quantities of silver. Nanotechnology cuts the demand for raw materials and reduces the mineral load on environment.
Benefits for the healthcare sector
Researchers at Åbo Akademi University have special expertise on cellulose-based materials. The effects of different coatings on bacteria are tested at the University of Turku.
“We start by developing technology that allows us to study bacterial responses to different antibacterial coatings. Then we move on to investigate how the coatings work in practice,” says Erkki Eerola, Adjunct Professor in the Medical Microbiology and Immunology Unit at the University of Turku.
“All the scientific evidence indicates that coatings can prevent the growth of bacteria. Our research has the potential to bring substantial benefits to healthcare systems and attract widespread commercial interest,” Eerola says.