Functionalisation of Graphene Sensor Surfaces for the Specific Detection of Biomarkers

Abstract

We report on a controllable and specific functionalisation route for graphene field‐effect transistors (GFETs) for the recognition of small physiologically active molecules. Key element is the noncovalent functionalisation of the graphene surface with perylene bisimide (PBI) molecules directly on the growth substrate. This Functional Layer Transfer enables the homogeneous self‐assembly of PBI molecules on graphene, onto which antibodies are subsequently immobilised. The sensor surface was characterised by atomic force microscopy, Raman spectroscopy and electrical measurements, showing superior performance over conventional functionalisation after transfer. Specific sensing of small molecules was realised by monitoring the electrical property changes of functionalised GFET devices upon the application of methamphetamine and cortisol. The concentration dependent electrical response of our sensors was determined down to a concentration of 300 ng ml−1 for methamphetamine.

Sensitivity-Enhancing Strategies of Graphene Field-Effect Transistor Biosensors for Biomarker Detection

“…Reproduced with permission. 83 Copyright 2023, Angewandte Chemie. (c) Immobilizing amino-modified probes based on PASE cross-linking.…”

“…Self-assembled monolayers (SAMs) have been introduced as a cutting-edge noncovalent method for graphene functionalization in GFET biosensing. 92 Laura et al 83 utilized perylene bisimide (PBI) SAMs for the noncovalent functionalization of graphene, creating GFET biosensors that detect methamphetamine and cortisol effectively (Figure 3b). The PBI's perylene linker noncovalently binds to the graphene surface, enhancing the biosensor's selectivity and reproducibility.…”

“…(b) Noncovalent functionalization of the graphene surface with PBI molecules directly on the growth substrate. Reproduced with permission 83. Copyright 2023, Angewandte Chemie.…”

Asymmetric Schottky Barrier-Generated MoS2/WTe2 FET Biosensor Based on a Rectified Signal

“…However, the commonly used signals in FET biosensors are referred to as “absolute value signals”. These include Dirac voltage, threshold voltage V th , source-drain current I ds , and others [ 4 , 5 , 6 , 7 ]. These “absolute value signals” directly collect and process the specific changes in biomolecules.…”

Aromatic Ring–Mediated Nonspecific Signaling Mechanism and Nafion‐Dominated Solution in Graphene Field‐Effect Transistor–Based Nucleic Acid Biosensors

“…[ 6 ] However, during the actual detection process, other components in the sample beside the target molecule could nonspecifically adsorb to the graphene surface and disturb its surface charge. [ 7 ] The nonspecific adsorption causes the graphene Dirac point shifts by the doping effect, resulting in nonspecific signals and weak signal purity. [ 8 ]…”