Researchers from Friedrich Schiller University Jena, CNM Technologies, NOXXON Pharma, APTARION Biotech and Radboud University Medical Center have developed graphene field effect transistor (GFET) sensors based on van der Waals (vdW) heterostructures of single-layer graphene layered with a molecular ≈1 nm thick carbon nanomembrane (CNM).
1 / 1Schematic illustration of the fabrication steps of the l-AP/PEG-CNM GFET sensors. Credit: Advanced Materials
The CNM acts as an ultrathin molecular interposer between the graphene channel and the analyte and allows bio-functionalization without impairing the graphene properties including its charge carrier mobility.
To achieve specificity and reliability in the detection of biomarkers in real patient samples, the functionalization incorporates biostable aptamers in the non-natural l-configuration and hydrophilic polyethylene glycol for avoiding non-specific adsorption.
A rapid (≈5 min) detection of the clinically relevant inflammatory mediator CXCL8/IL-8 within the concentration range of 0.5 – 500 pM (5 – 5000 pg ml−1) was demonstrated in nasal swab samples collected from patients with respiratory tract infections. This detection range may aid in diagnostics of early-stage infectious diseases making the reported approach promising for the development of future medical tools.
The miniaturized GFET-based biosensors enabled ultrasensitive and specific detection of chemokines in clinical samples in a concentration range relevant for medical diagnostics. In their work, the team implemented strategies to mitigate the key challenges such as non-specific binding and interference from proteins in UTM and mucus.
The developed methodology holds great promise for development of sensors capable of detecting multiple biomarkers in patient samples for monitoring various diseases without any enzymatic amplification. Moreover, as the detection principle is purely electrical, this approach holds promise to support the development of small and fast point-of-care devices for various applications, e.g., for diagnosis of infection by measuring host responses during a pandemic situation.
