Ultraviolet light to inactivate novel coronavirus

By Elton Alisson  |  FAPESP Innovative R&D – BioLambda, a biotech startup based in São Paulo City, Brazil, spent several years developing devices that emit ultraviolet-C radiation (UVC) to kill germs for use in food processing plants and drug factories, among other sectors. With the advent of the COVID-19 pandemic, the firm won support from FAPESP’s Innovative Research in Small Business Program (PIPE) to fast-track the development of a line of equipment for decontamination of face shields, surfaces, workspaces, and air, in a drive to reduce the risk of infection by SARS-CoV-2.

Some of the equipment is already on sale, including a handheld device for use in decontaminating telephones, keyboards, door handles, and groceries, as well as others for use in decontaminating air, N95 respirators, and cloth face masks. Another product line including ambient air decontamination units for smaller spaces will be launched soon.

“Tests performed in a biosafety level 3 [BSL-3] laboratory showed that even our least powerful device, which is the portable surface decontaminator, eliminates 99.9% of the viral load in less than a second,” Caetano Sabino, founder of the startup, told Innovative R&D.

The equipment is used by business organizations to decontaminate objects and spaces, and by homeowners to disinfect groceries and other purchases, for example.

“The system is extremely fast and effective,” Sabino said. “It leaves no residues, doesn’t degrade materials, and can be used on both simple surfaces such as metal or plastic and on more complicated ones such as parcel packaging, paper, fabric, foods, and appliances, on which disinfectant can’t be used.”

To guarantee microbicidal efficacy the devices are based on two main parameters: irradiance, defined as light power divided by area covered; and exposure time resulting in UVC dosage.

The wavelength used by BioLambda is 254 nanometers (nm). This dosage assures germicidal efficacy for bacteria, parasites, DNA viruses, and RNA viruses like SARS-CoV-2, according to Sabino and researchers at the University of São Paulo (USP) who authored a study published in the journal Photodiagnosis and Photodynamic Therapy.

Ultraviolet light at wavelengths above 180 nm can be a health hazard, causing eye damage, skin cancer, and aging. The skin and eyes must never be exposed to UVC. “Ultraviolet light can’t be used to decontaminate people or animals, only inanimate objects,” Sabino stressed.

The technology is germicidal because the pathogens’ RNA or DNA absorbs light in the UVC band, and the UVC radiation triggers a photoaddition reaction with nearby molecules, generating photoproducts that distort the structure of the RNA or DNA and inhibit the functions of this genetic material.

The bulbs in the equipment developed by BioLambda have a superimposed emission spectrum to absorb as much of the genetic material as possible and achieve the high-efficiency rating mentioned earlier. “Our keystones are safety and efficacy. We validate our equipment microbiologically and operationally in real-world spaces and independent laboratories,” Sabino said.

UVSurface, the handheld device, was validated at the BSL-3 facility in the University of São Paulo’s Biomedical Sciences Institute (ICB-USP). UVAir was validated at São Leopoldo Mandic Dental School in Campinas. The tests showed that the equipment reduced air contamination by 99.96% in 15 minutes.

“The tests were performed in a group clinic at the dental school where six dentists routinely work at the same time. This proves that the equipment can run uninterruptedly with people present in a wide array of workspaces,” Sabino said.

The firm already sells two models – one for areas up to 150 square meters (m²), and the other for up to 75 m². Both are designed to be used in industrial plants, hospitals, and offices. Within days it will launch two other models, for use in smaller areas (34 m² and 15 m²) such as conference rooms or dentists’ offices.

UVAir is made of stainless steel and has air exhaust fans and 254 nm UVC bulbs. On its way out the air is trapped for about two seconds in a mirrored chamber containing low-pressure mercury vapor bulbs that produce high-power UVC light, and is then expelled into the outside environment.

“The UVC is entirely contained within the device and doesn’t represent any health hazard at all,” Sabino said.

Forthcoming product launches

BioLambda has developed other products for ambient decontamination and is preparing to launch them soon. One is fixed to the ceiling and has redundant sensors that activate the system when people enter the space. It can also be switched on and off by remote control.

“This unit is designed for use in a range of workspaces, such as doctors’ and dentists’ offices, elevators, and washrooms,” Sabino said.

Hosted by the healthcare startup incubator run by the Albert Einstein Jewish-Brazilian Charitable Society (SBIBAE) in São Paulo, BioLambda is partnering with SBIBAE to develop a remotely operated mobile unit to decontaminate hospital spaces.