An FET-type charge sensor for highly sensitive detection of DNA sequence.
We have fabricated an field effect transistor (FET)-type DNA charge sensor based on 0.5 microm standard complementary metal oxide semiconductor (CMOS) technology which can detect the deoxyribonucleic acid (DNA) probe's immobilization and information on hybridization by sensing the variation of drain current due to DNA charge and investigated its electrical characteristics. FET-type charge sensor for detecting DNA sequence is a semiconductor sensor measuring the change of electric charge caused by DNA probe's immobilization on the gate metal, based on the field effect mechanism of MOSFET. It was fabricated in p-channel (P) MOSFET-type because the phosphate groups present in DNA have a negative charge and this charge determines the effective gate potential of PMOSFET. Gold (Au) which has a chemical affinity with thiol was used as the gate metal in order to immobilize DNA. The gate potential is determined by the electric charge which DNA possesses. Variation of the drain current versus time was measured. The drain current increased when thiol DNA and target DNA were injected into the solution, because of the field effect due to the electrical charge of DNA molecules. The experimental validity was verified by the results of mass changes detected using quartz crystal microbalance (QCM) under the same measurement condition. Therefore it is confirmed that DNA sequence can be detected by measuring the variation of the drain current due to the variation of DNA charge and the proposed FET-type DNA charge sensor might be useful in the development for DNA chips.
Kim
Dong-Sun
DS
School of Electronic & Electrical Eng., Kyungpook National University, 1370 Sangyuk-dong, Buk-gu, Daegu 702-701, South Korea.
Jeong
Yong-Taek
YT
Park
Hey-Jung
HJ
Shin
Jang-Kyoo
JK
Choi
Pyung
P
Lee
Jong-Hyun
JH
Lim
Geunbae
G
D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004247:DNA / Q000032:analysis* / Q000737:chemistry; D015342:DNA Probes / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017403:In Situ Hybridization / Q000295:instrumentation* / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA / Q000295:instrumentation* / Q000379:methods; D014159:Transducers; D014173:Transistors, Electronic
D020099:Coated Materials, Biocompatible; D015342:DNA Probes; D004247:DNA