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A new light-activated material protects masses of people by killing viruses and superbugs

Published on 16.12.2021
Tampere University
LASU-tutkimusryhmä Festia-laboratoriossa
LASU reasearch group was photographed in Festia laboratory at Hervanta Campus. Left in front Tuula Heinonen, Lijo George and Zafar Ahmed, and in back Nikita Durandin, Ville Santala and Alexander Efimov. Photo: Jonne Renvall / Tampere University
Researchers at Tampere University have developed a light-activated dye that destroys bacteria, fungi, and viruses on the surface of textiles. The ground-breaking innovation called LASU (light-activated antimicrobial substance) may be used, for example, in face masks against airborne diseases like COVID-19 and drug-resistant bacteria.

For the last five years the researchers have developed a novel light-activated material which becomes self-disinfecting under light and can be used to protect people against drug-resistant infections and viruses a well as many types of microorganisms. According to the research group leader, Doctor Alexander Efimov, the innovative LASU patent family was recently sold to Plasmonics Oy, a Finnish start-up company, which will continue to commercialise it.

“We have demonstrated that the LASU material is more stable and efficient than the best photosensitisers known to date, and what is most important, it works under regular indoor light. It is also suitable for mass production. The material can be prepared by simple dyeing to be effectively self-disinfecting in real life settings. We have tested the hazards according to standards and LASU can be used for items that come to contact with human skin,” Efimov says.

Treatment with the LASU dye produces self-disinfecting materials that are effective against many types of microorganisms simultaneously, such as bacteria, fungi, and viruses including unknown strains.

“This makes LASU a perfect solution against future pandemics and virus mutations. LASU-treated materials can be used, for example, for personal protection and paramedic equipment in crisis and epidemic area and as a preventive measure against bioterrorism,” says Pasi Keinänen, General Manager of Plasmonics.

Dye that is durable, easy-to-use, and harsh on superbugs

The core of the new approach is using photodynamic inactivation of pathogens (PACT). Upon light irradiation, LASU employs a photosensitiser that generates reactive oxygen species (ROS) which destroy the treated cells via oxidative action.

“PACT has major advantages. First, photoinactivation is a universal process affecting all pathogens simultaneously including fungi, viruses, and undetected microbes. Second, as a general oxidation process, phototoxic action is effective against multi-drug resistant pathogens. Thirdly, PACT does not induce resistivity in the treated microorganisms,” Efimov explains.

The dyed materials are exceptionally effective against antibiotic-resistant E. coli and A. baylyi, methicillin-resistant S. aureus and vancomycin-resistant E. faecium as well as Candida fungi and the HCoV-229 coronavirus. 

“In addition, the stable but water-soluble dye binds readily to textiles and other materials. The dyed material is stable against detergents and photobleaching. It can be easily reapplied when needed, and it prevents the growth of resistant strains and superbugs making it safe to use against multi drug resistant pathogens,” Efimov adds.

When LASU is used, a 30-minute illumination with a conventional indoor light improves the inactivation rate of bacteria, fungi, and viruses on surfaces over 10,000-fold.

A huge need for personal protection in mass quarantines

The recent swine flu and Ebola epidemics and the COVID-19 pandemic show that self-disinfecting textiles for human protection are urgently needed.

“This far, it has not been possible to safely reactivate and reuse personal protection masks and cloths or to quickly mass produce such items. This means that there are no solutions to ensure sufficient personal protection in mass quarantines in personal use or in, for example, elderly care, kindergartens or schools,” Efimov says.

The burden is worsened by the spreading of hospital acquired infections (HAIs). Approximately 1 out of 18 inpatients acquires a HAI, which directly causes 40,000 deaths annually in EU countries alone. Most of the infections are caused by multidrug-resistant strains of S. aureus (MRSA), E. coli, and Enterecoccus and Acinetobacter strains. The currently used self-disinfecting materials that contain antibiotics, various biocides, and copper or silver coatings, have serious drawbacks such as the rapid loss of activity and the stimulation of drug-resistant strains.

In 2017, the research group, consisting of Ville Santala, Lijo George and Efimov applied for the first patent for LASU. The group has also published three peer-reviewed articles on their innovation, and it was the topic of Lijo George’s doctoral dissertation in 2018.

“In 2019–2020, we had a Business Finland-funded project called TUTLi for broader patenting, pilot production and hazards testing. We also had the chance to test our innovation against the HCoV229e coronavirus and LASU proved to be effective,” says Efimov.

“I am grateful to my research partners Professor Ville Santala, Doctor Zafar Ahmed, Doctor Natalia Grammatikova, Professor Tuula Heinonen and Doctor Nikita Durandin. It is their invaluable contribution and the financial support of our university and BusinessFinland that made the project so successful,” Efimov adds.

Further information

Alexander Efimov
+358 40 561 3419
alexandre.efimov [at]