Graphene field-effect transistor microarray with simple preparation method, good stability, and high sensitivity for...

Graphene field-effect transistor (GFET) microarray with multiple channels, minimal size, high detection flux and high sensitivity demonstrates considerable promise for bioassay, clinical diagnosis, and health surveillance. However, their widespread application is hindered by the high cost, complex fabrication process, and poor analytical performance in aqueous systems. To address these issues, a simple method integrated with drop-casting, vapor chemical reduction, low temperature heat treatment, and oxygen plasma treatment is developed for the fabrication of highly stable and sensitive 8-channel GFET microarray on flexible polyethylene terephthalate substrate. The microarray could maintain good electrical performance in aqueous systems for up to 32 days and good recyclability against several high-low temperature treatments. The strong adhesion between the substrate and reduced graphene oxide facilitates the easy fabrication of graphene oxide/reduced graphene oxide heterostructure channels with both high electric conductivity and plenty carboxyl groups, which significantly enhance the probe density and ultimately lower the detection limits for interleukin-6 and DNA to fM levels. Additionally, the biosensor reliably quantified interleukin-6 in complex septic patient serum. Given the good analytical performances and the simple preparation strategy, this method may pave the way for the practical use of GFET microarray for bioassay.