Genetically Engineered Antibody Functionalized Platinum Nanoparticles Modified CVD‐Graphene Nanohybrid Transistor for the Detection of Breast Cancer Biomarker, HER3

Abstract

Biosensors based on graphene field effect transistors (GFETs) decorated with antibody‐functionalized platinum nanoparticles (PtNPs) are developed for the quantitative detection of breast cancer biomarker HER3. High‐quality chemical vapor deposited graphene is prepared and transferred over gold electrodes microfabricated on an SiO2/Si wafer to yield an array of 52 GFET devices. The GFETs are modified with PtNPs to obtain a hybrid nanostructure suitable for attachment of HER3‐specific, genetically engineered thiol‐containing single‐chain variable fragment antibodies (scFv) to realize a biosensor for HER3. Physical and electrical characterization of Bio‐GFET devices is carried out by electron microscopy, atomic force microscopy, Raman spectroscopy, and current–gate voltage measurements. A concentration‐dependent response of the biosensor to HER3 antigen is found in the range 300 fg mL−1 to 300 ng mL−1 and is in quantitative agreement with a model based on the Hill–Langmuir equation of equilibrium thermodynamics. Based on the dose–response data, the dissociation constant is estimated to be 800 pg mL−1, indicating that the high affinity of the scFv antibody is maintained after immobilization. The limit of detection is 300 fg mL−1, showing the potential for PtNP/G‐FETs to be used in label‐free biological sensors.