Versatile Graphene-Based Platform for Robust Nanobiohybrid Interfaces

TL;DR

This paper presents a controlled covalent functionalization method for graphene using thiol chemistry, enabling stable attachment of nanomaterials and biomolecules for advanced bioelectronic and sensing applications.

Contribution

It introduces a novel ultrahigh vacuum covalent functionalization technique for graphene that preserves electronic properties and allows versatile nanobiohybrid interface development.

Findings

Covalent attachment of metal nanoparticles and DNA aptamers to graphene was achieved and characterized.

Functionalized graphene retained its electronic properties and bio-recognition capabilities.

The approach was successfully integrated into graphene-based biosensing devices.

Abstract

Technologically useful and robust graphene-based interfaces for devices require the introduction of highly selective, stable, and covalently bonded functionalities on the graphene surface, whilst essentially retaining the electronic properties of the pristine layer. This work demonstrates that highly controlled, ultrahigh vacuum covalent chemical functionalization of graphene sheets with a thiol-terminated molecule provides a robust and tunable platform for the development of hybrid nanostructures in different environments. We employ this facile strategy to covalently couple two representative systems of broad interest: metal nanoparticles, via S-metal bonds, and thiol-modified DNA aptamers, via disulfide bridges. Both systems, which have been characterized by a multi-technique approach, remain firmly anchored to the graphene surface even after several washing cycles. Atomic force microscopy images demonstrate that the conjugated aptamer retains the functionality required to recognize a target protein. This methodology opens a new route to the integration of high-quality graphene layers into diverse technological platforms, including plasmonics, optoelectronics, or biosensing. With respect to the latter, the viability of a thiol-functionalized chemical vapor deposition graphene-based solution-gated field-effect transistor array was assessed.