Biosensing Platform Simultaneously Detects Vitamin C and SARS-CoV-2

Several studies have demonstrated that vitamin C, an essential nutrient for immune function, can help manage symptoms of viral respiratory infections like SARS-CoV-2. During the COVID-19 pandemic, at-home testing became essential for determining when to isolate or wear a mask. While existing vitamin C tests are bulky and costly, researchers have now developed a portable, wireless device that can simultaneously detect SARS-CoV-2 and vitamin C levels. This dual testing approach could help individuals and healthcare providers determine the most effective treatment, such as providing vitamin C supplementation for low levels while considering alternative options for normal or high levels.

In their study, researchers at Penn State (University Park, PA, USA) selected vitamin C and SARS-CoV-2 to demonstrate their testing method's versatility. They used these two common biomarkers to showcase both types of sensors: those with a capture element to detect target molecules and those without one. The device works by processing a small saliva sample and wirelessly transmitting the results to the user’s phone. This allows individuals to monitor their vitamin C levels and adjust their diet or supplements accordingly to potentially improve their symptoms.

Image: The biosensing platform incorporates two-pass laser induced graphene with commercial transistors to simultaneously test for SARS-CoV-2 and vitamin C (Photo courtesy of Heshmat “Amir” Asgharian / Penn State)

To build the sensing platform, the team explored various properties of laser-induced graphene, a highly sensitive, thin material created using precise laser printing techniques. They examined its porosity, electrical properties, and surface roughness to optimize the sensor’s sensitivity. The study, published in ACS Applied Materials & Interfaces, found that two laser printing passes significantly improved the sensor's sensitivity and detection limit for both biomarkers. Similar to glucose monitoring strips used by diabetics, the inexpensive, single-use sensor, built on a plastic substrate, is easy to manufacture, and the testing module is reusable.

“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,” 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.