High Yield and Scalable Fabrication of Nano/Bio Hybrid Graphene Field Effect Transistors for Cancer Biomarker Detection

Graphene field effect transistors (GFETs) hold tremendous promise for use as biosensor transduction elements due to graphene's high mobility, low noise and all-surface structure with every atom exposed to the environment. We developed a GFET array fabrication based on two approaches, pre-patterned transfer and post-transfer photolithography. Both approaches are scalable, high yield, and electrically stable. Functional groups for protein immobilization were added to the GFET using various bi-functional pyrene-based linkers. One approach immobilized an azide engineered protein through a ``Staudinger Reaction'' chemistry with NHS-phosphine reacting with a 1-aminopyrene linker. Another approach bound an engineered antibody via 1-pyrene butanoic acid succinimidyl ester, where an amine group of the antibody reacts to the succinimide of the linker. GFETs were studied by Raman spectroscopy, AFM and current-gate voltage (I-Vg) characterization at several steps of the fabrication process. A sensing response was obtained for a breast cancer biomarker (HER2) as a function of target concentration. We have started to design multiplexed sensor arrays by adding several functional groups to GFETs on a single chip. Simultaneous detection with these devices will be discussed.