A dielectric-modulated field-effect transistor for biosensing.
Interest in biosensors based on field-effect transistors (FETs), where an electrically operated gate controls the flow of charge through a semiconducting channel, is driven by the prospect of integrating biodetection capabilities into existing semiconductor technology. In a number of proposed FET biosensors, surface interactions with biomolecules in solution affect the operation of the gate or the channel. However, these devices often have limited sensitivity. We show here that a FET biosensor with a vertical gap is sensitive to the specific binding of streptavidin to biotin. The binding of the streptavidin changes the dielectric constant (and capacitance) of the gate, resulting in a large shift in the threshold voltage for operating the FET. The vertical gap is fabricated using simple thin-film deposition and wet-etching techniques. This may be an advantage over planar nanogap FETs, which require lithographic processing. We believe that the dielectric-modulated FET (DMFET) provides a useful approach towards biomolecular detection that could be extended to a number of other systems.
Im
Hyungsoon
H
Nano-Oriented Bio-Electronic Lab, School of Electrical Engineering and Computer Science, Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
Huang
Xing-Jiu
XJ
Gu
Bonsang
B
Choi
Yang-Kyu
YK
D015374:Biosensing Techniques / Q000295:instrumentation*; D001710:Biotin / Q000032:analysis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D036103:Nanotechnology / Q000295:instrumentation*; D012680:Sensitivity and Specificity; D019809:Streptavidin / Q000032:analysis*; D014173:Transistors, Electronic
D001710:Biotin; D019809:Streptavidin