High‐Performance Flexible and Printed Graphene‐Field Effect Biosensor for Ferritin Detection

Abstract

A flexible and printed field‐effect biosensor with a graphene channel (Gr‐FET biosensor) is designed and characterized to detect ferritin. The biosensor offers an onboard Ag/AgCl gate to give stable transfer characteristics with a significantly low gate leakage current of 0.06% of the minimum drain current. Further, the proposed Gr‐FET shows 1.5–3 times higher transconductance (gm) with a value of gm,hole up to 400 µS and gm,electron up to 250 µS, compared to the reported printed electrolyte‐gated Gr‐FET on flexible substrates. The Gr‐FET operation is also optimized to have a minimal hysteresis effect for reliable sensing operation. The Gr‐FET shows fairly linear characteristics at a low ferritin concentration (0.05–0.5 µg L−1) with sensitivity as high as ≈230 mV/(µg L−1) and a very low limit of detection (LOD) ≈27 ng L−1. Given the cost‐effective fabrication process and scalability, the proposed printed Gr‐FET biosensor can be deployed on a large scale for early diagnosis of iron deficiency anemia.