Direct Electrical Probing of Rolling Circle Amplification on Surface by Aligned-Carbon Nanotube Field Effect Transistor

E-mail: wsyun87@skku.eduReceived October 3, 2012, Accepted January 6, 2013Rolling circle amplification (RCA) of DNA on an aligned-carbon nanotube (a-CNT) surface was electricallyinterfaced by the a-CNT based filed effect transistor (FET). Since the electric conductance of the a-CNT willbe dependent upon its local electric environment, the electric conductance of the FET is expected to give a verydistinctive signature of the surface reaction along with this isothermal DNA amplification of the RCA. The a-CNT was initially grown on the quartz wafer with the patterned catalyst by chemical vapor deposition andtransferred onto a flexible substrate after the formation of electrodes. After immobilization of a primer DNA,the rolling circle amplification was induced on chip with the a-CNT based FET device. The electricconductance showed a quite rapid increase at the early stage of the surface reaction and then the rate of increasewas attenuated to reach a saturated stage of conductance change. It took about an hour to get the conductancesaturation from the start of the conductance change. Atomic force microscopy was used as a complementarytool to support the successful amplification of DNA on the device surface. We hope that our results contributeto the efforts in the realization of a reliable nanodevice-based measurement of biologically or clinicallyimportant molecules.Key Words : Electric probing, Rolling circle amplification, Aligned-carbon nanotube, NanobiosensorIntroductionSensitive detection of a target DNA by nanoscaled elec-tronic devices has been of great interest since its promisingadvantages to be applied in various bio and medical fields ofsciences and technologies.