A Flexible and Regenerative Aptameric Graphene–Nafion Biosensor for Cytokine Storm Biomarker Monitoring in Undiluted Biofluids toward Wearable Applications

Wearable sensors that can conveniently detect cytokine levels in human biofluids are essential for assisting hospitals to maximize the benefits of anti-inflammatory therapies and avoid cytokine storm with high mortality. Measurement of cytokine levels in biofluids still remains challenging for existing sensors due to high interferences from the background. Here, this challenge is overcome through developing a flexible and regenerative aptameric field-effect transistor biosensor, consisting of a graphene-Nafion composite film, for detecting cytokine storm biomarkers in undiluted human biofluids. The composite film enables the minimization of nonspecific adsorption and empowers the renewability to the biosensor. With these capabilities, the device is capable of consistently and sensitively monitoring cytokines (e.g., IFN-γ, an inflammatory and cancer biomarker) in undiluted human sweat with a detection range from 0.015 to 250 nM and limit of detection down to 740 fM. The biosensor is also shown to incur no visible mechanical damages and maintian consistent sensing response throughout the regenerative (up to 80 cycles) and crumpling (up to 100 cycles) tests. Experimental results demonstrate that the biosensor is expected to offer opportunities for developing wearable biosensing systems for distinguishing acute infectious disease patients and monitoring of patients' health conditions in daily life.