AVS 58th Annual International Symposium and Exhibition
    Nanometer-scale Science and Technology Division Wednesday Sessions
       Session NS-WeM

Paper NS-WeM10
Horizontally Aligned Carbon Nanotubes on Quartz Substrate for Electrolyte-Gated Chemical and Biological Sensing

Wednesday, November 2, 2011, 11:00 am, Room 203

Session: Carbon-Based Nanomaterials
Presenter: Satoshi Okuda, Osaka University, Japan
Authors: S. Okuda, Osaka University, Japan
Y. Ohno, Osaka University, Japan
K. Maehashi, Osaka University, Japan
K. Inoue, Osaka University, Japan
K. Matsumoto, Osaka University, Japan
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Electrolyte-gated carbon nanotube field-effect transistors (CNTFETs) based highly sensitive chemical and biological sensors were demonstrated. Dense, well-aligned CNTs grown on quartz substrates were utilized as channels of CNTFETs. Using the large number of CNTs is a simple strategy to realize excellent performance of CNTFETs. First, the pH dependence of CNTFETs was measured in buffer solution ranging from pH 4.0 to 8.3 by monitoring the drain current (ID) in the CNTFET. Clearly and stepwise increases in ID were observed against the change in pH in the solution. The detection limit for changes in pH was estimated to be 0.015, which is a superior characteristic to that of conventional CNTFETs. The result indicates that CNTFETs on quartz substrates can be used as highly sensitive pH sensors. Moreover, label-free biomolecule sensing was demonstrated. The target protein was a class of antibody, immunoglobulin E (IgE). To achieve the electric detection of IgE, we used aptamer-modified CNTFETs with multichannel. Then, binding event of target IgE onto the aptamers was detected. IgE-concentration dependence measurements revealed that we succeeded in detection of nM quantities of IgE. In conclusion, electrolyte-gated multichannel CNTFETs will be useful for highly sensitive chemical and biological sensors.