‘LEGO-Box’ Solution for the Shortage of Corona Masks

UV sterilizer for N95 masks developed by Lehigh University and St. Luke’s (Source: Lehigh U.)

Right around the time in mid-March when Lehigh University moved to remote learning and researchers began to shut down on-campus labs, Nelson Tansu, professor in the department of electrical and computer engineering (ECE), received an email from Dr Christopher Roscher, an anesthesiologist at St. Luke’s University Health Network.

Roscher knew that a shortage of N95 masks would place at even higher risk the doctors and nurses treating Covid-19 patients. As St. Luke’s worked to increase its supply of essential personal protective equipment (PPE), the hospital needed a safe and effective way to extend the use of its existing supply. Roscher had been conducting personal research about the use of UV light for decontamination and discovered peer-reviewed literature in medical journals which suggested that, in a pandemic situation, using UV light could be a reasonable alternative if more masks were not available. He asked Tansu, who is also the director of Lehigh’s Center for Photonics and Nanoelectronics (CPN) and a fellow of the US National Academy of Inventors (NAI), if he thought a Lehigh team could help.

“St. Luke’s, like many other hospitals, is trying to conserve what we have,” says Roscher. “We approached this idea understanding that in an ideal world we would have a new mask for everybody who needed one, but the reality of the situation is that we need to conserve.”

Tansu’s response to that initial email was swift: Yes, he thought it could be done. The next day, he gathered an enthusiastic team of volunteers – staff members and students from the CPN and Lehigh’s department of electrical and computer engineering (ECE), all practicing social distancing in their own homes. They designed, completed the engineering fabrication of, and installed the device in 2.5 weeks – without ever stepping foot on Lehigh’s campus or meeting face to face.

The high-throughput UV sterilization system, now in use at St. Luke’s, can decontaminate two hundred N95 masks every eight minutes. The system, formally named the “High-Throughput Symmetrical and Non-Shadowing Ultraviolet Sterilization System,” but which the team at St. Luke’s has nicknamed the “bug zapper” due to its resemblance to the insect-killing device used by homeowners, “zaps” the masks with UV-C light. This specific range of ultraviolet light can cause changes in the DNA and RNA of viruses and other pathogens, including the Coronavirus, effectively deactivating them. The team has filed two patent applications associated with the new invention.

The “bug zapper” has a large, octagonal metal frame with UV lights positioned at its center to achieve symmetrical UV-C irradiation on the N95 masks. Its targeted capacity is approximately three thousand N95 masks per day, but St. Luke’s can scale up to 10,000 masks per day if necessary.

The goal, says Tansu, was to use enough UV-C light to damage viruses and bacteria but retain the integrity of the N95 mask, which can be degraded more significantly over time by steam or chemicals. Staff members at St. Luke’s monitor exposures with a device called a radiometer, which measures the amount of light irradiation to which the masks are exposed, and they take care to protect their own skin and eyes when sterilizing the masks.

The Lehigh / St. Luke’s team of inventors (L-R): Anthony L. Jeffers, Nelson Tansu, Jay Johnson, Grant Reed, Theodore L. Bowen, Renbo Song, Christopher Roscher, Ankhitha Manjunatha, Axel Y. Tansu, Eric Tesoriero. Not pictured: Adela Gozali Yose (Source: Lehigh U.)

The team’s initial design was cylindrical in shape to ensure even exposure, but that approach would require St. Luke’s staff to individually rotate each of the two hundred masks 180 degrees halfway through the exposure to decontaminate each side, says Tansu.

Tansu’s 8-year-old son, Axel, joined the project with a critical contribution to the device’s high throughput rate. He suggested that the device should have an octagonal shape instead, to allow for St. Luke’s staff to easily flip the frame on each of the eight sides to rotate the masks, rather than rotating each mask individually.

In an effort to maintain social distancing guidelines and avoid putting anyone at risk, the team then divided the project into individual tasks to build the device modularly. After they determined the materials they would need, team members had the materials delivered to their homes, where they worked, often in garages, on their assigned components, completing them in under five days. “Then after that, they assembled it like a LEGO box,” says Tansu.

“We are very thankful for the opportunity to help to design and build the high-throughput N95 mask sterilization system in response to the Covid-19 crisis,” says Tansu. “At the end of the day, medical professionals are the ones who are taking the high responsibility in responding to this Coronavirus pandemic issue. They are at very high risk on the job, and I’m glad that our team is able to at least help a little bit in assuring them that their masks are sterilized.” (Source: Lehigh U.)

Links: Center for Photonics and Nanoelectronics, P.C. Rossin College of Engineering and Applied Science, Sinclair Lab, Lehigh University, Bethlehem, PA, USASt. Luke’s University Health Network (SLUHN), Bethlehem, PA, USA

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