Bioelectronics and Interfaces Using Monolayer Graphene

Abstract

Graphene is expected to revolutionize several application areas ranging from portable energy conversion and storage to miniaturized biosensors for medical applications. In this endeavor, the control of surface characteristics is an essential aspect for understanding fundamental phenomena occurring at the graphene‐liquid interface. In this comprehensive review, we address recent progress in the investigation of the interfacial characteristics of monolayer graphene and methods for modulating the physical and chemical properties of this interface. We focus on the electrochemistry and field‐effect measurements in liquid, which provide an improved understanding of the unique graphene‐liquid interface, with due consideration of the influence of the underlying substrate and structural defects in graphene. Finally, we present reported examples of using single graphene monolayers in miniaturized devices for realizing sensors, neural interfaces and batteries.

Ultrasensitive Materials for Electrochemical Biosensor Labels

“…Graphene and graphene-related materials are renowned for exceptional electrical, chemical, thermal, mechanical, and optical properties [ 51 , 52 , 53 , 54 , 55 ]. The significant interest of graphene and related materials in electrochemical applications is mainly due to the large surface area and the fast charge transfer kinetics [ 56 , 57 , 58 , 59 , 60 , 61 ]. These unique features also make them promising signaling labels for bio-recognition events in biosensing applications.…”

Advances on the Use of Graphene as a Label for Electrochemical Biosensors

“…One of the greatest challenges that are faced when developing a biosensor include the formation of a stable and specific layer of the biorecognition element. In order to achieve that on graphene surface: different functionalization strategies have been explored and compared, including physical adsorption, conjugation by covalent bonds or by the formation of affinity interactions (see Figure B); topological constraint of immobilized biorecognition elements have been investigated (see one example of DNA probe immobilization from different soldering points shown in Figure C); the kind and amount of surface functional groups have been tuned during graphene synthesis for the optimization of the bio‐conjugation process; large area CVD single‐layer graphene has been employed especially for biosensors based on for field effect transistors (see an example of bacteria detection on graphene‐FET modified with anti‐ E. coli antibody in Figure D) …”

“…Besides its exceptional optical, mechanical, chemical and thermal properties, graphene outstanding electrical conductivity, high electron mobility, fast charge transfer rate and large surface area are the principal reasons for its widespread usage in electrochemistry related applications …”

Colour-sensitive conjugated polymer inkjet-printed pixelated artificial retina model studied via a bio-hybrid photovoltaic device

“…Undoubtedly their ability to conduct ions, in addition to electrons and holes, opens a new communication channel with biology due to the importance of ion fluxes in biological systems 18 . Furthermore, these materials in an engineered nanoscale, including carbon nanotubes 19 , 20 graphene 21 , 22 and conjugated polymers 23 , 24 , have the potential to interact with biological systems on a molecular scale, offering unprecedented levels of control over physiological activity 25 , 26 .…”