Portable wireless device detects COVID and vitamin C

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Commercial transistors and laser-induced graphene have been combined at Penn State to make a portable and wireless device to simultaneously detect SARS-CoV-2 and vitamin C.

The biosensing platform developed by Penn State engineering researchers incorporates two-pass laser induced graphene with commercial transistors to simultaneously test for SARS-CoV-2 and vitamin C
The biosensing platform developed by Penn State engineering researchers incorporates two-pass laser induced graphene with commercial transistors to simultaneously test for SARS-CoV-2 and vitamin C - Heshmat 'Amir' Asgharian/Penn State

By simultaneously detecting the virus and vitamin C levels, the test could help individuals and their healthcare providers decide on more effective treatment options, the researchers said. Someone with low vitamin C levels may benefit from a supplemental boost, while someone with normal or high vitamin C levels may need to consider other options. The research is detailed in ACS Applied Materials & Interfaces. 

“There are several studies that show that vitamin C can help with managing the symptoms of viral respiratory infections like SARS-CoV-2,” said corresponding author Aida Ebrahimi, the Thomas and Sheila Roell Early Career Associate Professor of electrical engineering, of biomedical engineering and of materials science and engineering. “There are testing platforms for vitamin C, but they are bulky, expensive and not suitable for point-of-care, at home testing. Our device is portable, easy to operate and can detect vitamin C and SARS-CoV-2 simultaneously, with the option to add new target molecules to the same testing platform in the future.” 

Researchers chose to test vitamin C and SARS-CoV-2 for their clinical importance and to demonstrate the versatility of their testing approach. 

“We used vitamin C and SARS-CoV-2 as model targets to demonstrate the applicability of our approach for detecting biomarkers with the two common types of sensors used in the biosensors community: those with a capture element to ‘capture’ the target molecules, and those without one,” Ebrahimi said in a statement. “We used the molecules to show our improvement in the test’s functionality compared to existing methods.” 

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After processing a small sample of saliva, the device sends results wirelessly to a user’s cell phone, said Ebrahimi. Users can then continue to monitor their vitamin C levels at home and take a supplement or eat vitamin-rich foods to potentially improve their symptoms.  

To develop their sensing platform, the researchers investigated several parameters of laser-induced graphene, which is fabricated by a highly precise laser printing.

The team assessed its porosity, electrical properties and surface roughness to determine the best number of ‘passes,’ or layers, in which to print the sensors. 

The number of passes impacts the sensor’s sensitivity and limit of detection, which refers to the lowest concentration of a substance that can be detected within a certain confidence interval.  

“We showed that with two laser printing passes, known as two-pass laser induced graphene, the sensor sensitivity and the limit of detection improve significantly for both vitamin C and SARS-CoV-2,” said first author Heshmat ‘Amir’ Asgharian, a doctoral student in electrical engineering at Penn State. 

Similar to the small test strips that diabetes patients use for glucose monitoring, the one-time-use sensing device, which is made on a plastic substrate, is cheap and easy to manufacture, the researchers said, while the testing module is reusable.  

The US National Science Foundation and the National Institutes of Health supported this research.

 

point of care sensor
Wireless biosensor