Highly sensitive graphene biosensor by monomolecular self-assembly of receptors on graphene surface

• Published in: Applied physics letters Vol. 110; no. 20
• Main Authors: Kim, Ji Eun, No, Young Hyun, Kim, Joo Nam, Shin, Yong Seon, Kang, Won Tae, Kim, Young Rae, Kim, Kun Nyun, Kim, Yong Ho, Yu, Woo Jong
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 15-05-2017
• Subjects: Applied physics; Biomolecules; Biosensors; Biotin; Coupling (molecular); Graphene; Peptides; Proteins; Receptors; Response time; Self-assembly; Sensitivity; Sensors
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4983084

Graphene has attracted a great deal of interest for applications in bio-sensing devices because of its ultra-thin structure, which enables strong electrostatic coupling with target molecules, and its excellent electrical mobility promising for ultra-fast sensing speeds. However, thickly stacked receptors on the graphene's surface interrupts electrostatic coupling between graphene and charged biomolecules, which can reduce the sensitivity of graphene biosensors. Here, we report a highly sensitive graphene biosensor by the monomolecular self-assembly of designed peptide protein receptors. The graphene channel was non-covalently functionalized using peptide protein receptors via the π-π interaction along the graphene's Bravais lattice, allowing ultra-thin monomolecular self-assembly through the graphene lattice. In thickness dependent characterization, a graphene sensor with a monomolecular receptor (thickness less than 3 nm) showed five times higher sensitivity and three times higher voltage shifts than graphene sensors with thick receptor stacks (thicknesses greater than 20 nm), which is attributed to excellent gate coupling between graphene and streptavidin via an ultrathin receptor insulator. In addition to having a fast-inherent response time (less than 0.6 s) based on fast binding speed between biotin and streptavidin, our graphene biosensor is a promising platform for highly sensitive real-time monitoring of biomolecules with high spatiotemporal resolution.