Researchers from Penn State have combined commercial transistors and laser-induced graphene to create a portable and wireless device to detect SARS-CoV-2 and vitamin C at the same time.

The researchers explained that by simultaneously detecting the virus and vitamin C levels, the test might help individuals and their healthcare providers determine more effective treatment options.

“There are several studies that show that vitamin C can help with managing the symptoms of viral respiratory infections like SARS-CoV-2. 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,” the team noted. “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. We used the molecules to show our improvement in the test’s functionality compared to existing methods.”

The team explained that as soon as a saliva sample is processed, the device wirelessly sends results to a user’s smart phone to monitor their vitamin C levels at home. This enables the user to take action in the event vitamin C levels are low, for instance.

To construct this sensing platform, the team examined several parameters of laser-induced graphene, which is manufactured via highly precise laser printing. During this examination, the team assessed the laser induced graphene’s porosity, electrical properties and surface roughness to arrive at the best number of ‘passes,’ or layers, in which to print the sensors.

The researchers explained that the number of passes will impact the sensor’s sensitivity as well as limit of detection, which is a reference to the lowest concentration of a substance detectable within a specific confidence interval.

The team revealed that two laser printing passes — otherwise known as two-pass laser induced graphene — was the ideal number of passes in terms of sensor sensitivity and the limit of detection, both of which improved dramatically for vitamin C and SARS-CoV-2.