Chapter 4 - Graphene Functionalization for Biosensor Applications

Abstract

This chapter reviews the growth, chemical functionalization, and sensing applications of graphene. Techniques used to modify graphene in order to attach “bioreceptor” molecules, capable of specific and selective detection of target biomarkers, are reviewed. A range of different chemistries are discussed including methods used for exfoliated and solution-based graphene, as well as chemical vapor deposition (CVD) and epitaxial graphene. The suitability of different types of graphene for sensing applications will be discussed. Direct and indirect (using a modification of an adsorbed layer or polymer film on top of the graphene) functionalization techniques will be reviewed. Emphasis is placed on techniques suitable for fabricating devices on a wafer scale, using CVD and epitaxial graphene grown on SiC. Sensor device design and fabrication will be discussed. The effect of functionalization on the electrical transport properties, including carrier type and mobility, will be examined. Issues including characterization of sensor operation, reproducibility, and reliability will all be addressed. There are several advantages of graphene sensors over alternative sensor platforms such as carbon nanotubes or silicon nanowires. The main benefits of graphene for sensing applications will be highlighted in a comparison with other materials. Finally, the range of potential applications from DNA sensors to immunoassays to detection of food toxins will be reviewed.