Dielectric‐Modulated Biosensing with Ultrahigh‐Frequency‐Operated Graphene Field‐Effect Transistors. Issue 7 (6th January 2022)

• Record Type: Journal Article
• Authors: Zhang, Xiaoyan; Liu, Tingxian; Boyle, Aimee; Bahreman, Azadeh; Bao, Lei; Jing, Qiushi; Xue, Honglei; Kieltyka, Roxanne; Kros, Alexander; Schneider, Grégory F.; Fu, Wangyang
• Is Part Of: Advanced materials. Volume 34:Issue 7(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-06
• Subjects: dielectric modulation -- field effect -- graphene biosensors -- ionic screening -- ultrahigh frequency; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202106666
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Owing to their excellent electrical properties and chemical stability, graphene field‐effect transistors (Gr‐FET) are extensively studied for biosensing applications. However, hinging on surface interactions of charged biomolecules, the sensitivity of Gr‐FET is hampered by ionic screening under physiological conditions with high salt concentrations up to frequencies as high as MHz. Here, an electrolyte‐gated Gr‐FET in reflectometry mode at ultrahigh frequencies (UHF, around 2 GHz), where the ionic screening is fully cancelled and the dielectric sensitivity of the device allows the Gr‐FET to directly function in high‐salt solutions, is configured. Strikingly, by simultaneous characterization using electrolyte gating and UHF reflectometry, the developed graphene biosensors offer unprecedented capability for real‐time monitoring of dielectric‐specified biomolecular/cell interactions/activities, with superior limit of detection compared to that of previously reported nanoscale high‐frequency sensors. These achievements highlight the unique potential of ultrahigh‐frequency operation for unblocking the true potential of graphene biosensors for point‐of‐care diagnostic. Abstract : Electrolyte‐gated graphene field‐effect transistors (Gr‐FETs) are configured in reflectometry mode at ultrahigh frequencies (UHF), where the conductivity of high‐salt solutions, and thus the ionic screening is fully cancelled. By simultaneous characterization using field effect and UHF reflectometry, dielectric‐modulated Gr‐FET biosensors with high sensitivities are achieved.