In a study just pre-published on medRxiv, researchers from the University of Liege (Belgium) further proved the power of the protective dye Methylene Blue plus light in inactivating dangerous pathogens. The study concludes, "Methylene blue photochemical treatment of murine norovirus-contaminated masks reduced infectious viral titers by over four orders of magnitude."

While previous studies have demonstrated the efficacy of protective dyes against SARS-CoV-2, MHV, and others, no study had proven efficacy against the "harder-to-kill" norovirus on personal protective gear (PPE) until now.  

Norovirus is one of the most difficult to inactivate of the gastrointestinal human viruses. Researchers chose norovirus for this study so that proven success could be used to predict efficacy against other less resistant viruses. Per the study:

While enveloped viruses, surrounded by an outer lipid layer, are susceptible to inactivating treatments, non-enveloped viruses are known to be significantly more resistant. Amongst them, the small, non-enveloped human norovirus, recognized as the major global cause of viral gastroenteritis, is notorious for its tenacity in the face of decontamination and as such may be considered the gold standard for validating viral inactivation.

Per the CDC's Global Burden Report, the disease burden for norovirus is considered high, causing approximately 200,000 deaths annually worldwide. The National Foundation for Infectious Diseases (NFID) says norovirus, which is commonly referred to as the "stomach bug," causes millions of hospital visits each year.

The most common setting for norovirus outbreaks is in healthcare facilities, including long-term care facilities and hospitals. Per the CDC, "Over half of all norovirus outbreaks reported in the United States occur in long-term care facilities." Other common locations for outbreaks worldwide: cruise ships, schools, military bases, and restaurants.

The NFID states, "Noroviruses are highly contagious. You can get norovirus from an infected person, contaminated food or water, or by touching contaminated surfaces."

The recent study sought to decontaminate the norovirus on masks standard in the healthcare setting (respirators and surgical masks). With healthcare facilities being the most common location for outbreaks, the ability to decontaminate this virus on soft surfaces, especially masks, is beyond important. Researchers demonstrated that norovirus-inoculated surgical masks could be successfully decontaminated when treated with a 100 μM Methylene Blue formulation and exposed to 12,500-lux red light for 30 minutes.

Per the authors, "The protocol developed here thus solidifies the position of methylene blue photochemical decontamination as an important tool in the package of practical pandemic preparedness."

Dr. Tom Lendvay, Chief Medical Officer at Singletto, says, "Not only does this better prepare us for future pandemics and PPE shortages by providing a known way of safe, simple, affordable decontamination of masks for re-use, but the data can also inform how we can improve mask and PPE technology."

Singletto is working with PPE manufacturers now to embed its protective dye technology Oxafence, which uses Methylene Blue and other protective dyes, into masks, PPE, and other soft surfaces, thereby allowing them to continually decontaminate pathogens while in use.

The study entitled, "Of masks and methylene blue - the use of methylene blue photochemical treatment to decontaminate surgical masks contaminated with a tenacious small non-enveloped norovirus" was co-authored by Wielick, Fries, Dams, Razafimahefa, Heyne, Harcourt, Lendvay, Willaert, de Jeager, Haubruge, Thiry, and Ludwig-Begalla, and can be viewed on medRxiv:


November 15, 2021
Protective Dye Methylene Blue Plus Light Proven to Inactivate "Hard-to-kill" Norovirus

Singletto's Dr. Lendvay contributed to a New MB Study


May 22, 2021
Infection Control & Hospital Epidemiology Publishes Drs. Lendvay, Chen, et al. WHO-led DeMaND Study

The Infection Control & Hospital Epidemiology medical journal has published the peer-reviewed DeMaND study. Singletto’s Dr. Tom Lendvay served as Lead Author.


May 20, 2021
Top Doctor 2021: Singletto’s Lendvay Named by Seattle Magazine

Dr. Thomas Lendvay, Singletto’s Co-Founder and Chief Medical Officer was just named a “Top Doctor” by Seattle Magazine.


March 25, 2021
A Moral Obligation: Why the Former Providence President Wants Singletto Tech Out Now

Mike Butler spent over two decades in leadership at Providence Health, growing such from a $2 billion organization to $25 billion. Upon recently retiring, Mike knew he wanted to find ways to continue impacting the lives and health of others. Now at Singletto, Mike is on a mission to bring the novel Singletto technology to market – in healthcare and beyond. But, it’s not just a passion project … upon learning about the technology, Mike felt a moral obligation to get it in as many hands as possible. More with recently retired Providence Health President Mike Butler…


February 25, 2021
Hospital News: Light kills. SARS-CoV-2, That Is.

Singletto Advisor Dr. Belinda Heyne shares DeMaND study results on Hospital News.

Lacey Duffy

Customer Experience
February 12, 2021
CBC: This simple mix of dye and light could decontaminate masks for reuse

Dr. Belinda Heyne was recently featured in a CBC piece covering the DeMaND study’s findings and the life-giving potential of dye and light.