LABEL-FREE BIOMOLECULAR DETECTION USING CARBON NANOTUBE FIELD EFFECT TRANSISTORS

Abstract

Carbon nanotube field effect transistor (FET) type biosensors have been widely investigated as one of the promising platforms for highly sensitive personalized disease-monitoring electronic devices. Combined with high level cutting edge information technology (IT) infra systems, carbon nanotube transistor biosensors afford a great opportunity to contribute to human disease care by providing early diagnostic capability. Several key prerequisites that should be clarified for the real application include sensitivity, reliability, reproducibility, and expandability to multiplex detection systems. In this brief review, we introduce the types, fabrication, and detection methods of single-walled carbon nanotube FET (SWNT-FET) devices. As surface functionalization of the devices by which nonspecific bindings (NSBs) are efficiently prohibited is also another important issue regarding reliable biosensors, we discuss several key strategies about surface passivation along with examples of various biomolecules such as proteins, DNA, small molecules, aptamers, viruses, and cancer and neurodegenerative disease markers which have been successfully sensed by SWNT-FET devices. Finally, we discuss proposed detection mechanisms, according to which strategies for fabricating sensor devices having high sensitivity are determined. Two main mechanisms — charge transfer (or electrostatic gate effect) and Schottky barrier effect, depending on the place where biomolecules are adsorbed — will be covered.