Fabrication of ultrasensitive graphene nanobiosensors

The development of miniaturised systems for detection of disease biomarkers, at clinically relevant concentrations in biological samples, is key in the early diagnosis and monitoring of diseases. This paper presents the development of novel antibody functionalized epitaxial graphene devices for bio-sensing applications. Epitaxial graphene has been grown on silicon carbide (SiC) substrates under high vacuum and high temperature conditions (1200-1700°C). A generic electrochemical surface functionalisation chemistry, which can be used to attach a variety of "bio-receptors" to graphitic surfaces, has been developed. The attached bio-receptors are capable of specific and selective interaction with disease biomarkers. When a target biomarker molecule interacts with the "bio-receptor" functionalised surface, the charge density at that surface is affected. This change can be detected as an electrical signal from the biosensor, enabling highly sensitive detection of biomarker analytes.