Nanogap capacitors for label free DNA analysis

Joon Sung Lee, Yang Kyu Choi, Michael Pio, Jeonggi Seo, Luke P. Lee

Research output: Contribution to journalConference articlepeer-review

12 Scopus citations


Nanogap capacitors are fabricated for DNA hybridization detection. Without labeling, the nanogap capacitors on a chip can function as DNA microarray sensors. The difference in dielectric properties between single-stranded DNA and double-stranded DNA permits use of capacitance measurements to detect hybridization. To obtain high detection sensitivity, a 50 nm gap capacitor was fabricated using a Si-nanotechnology. To ensure proper measurement of DNA's dielectrical properties, the probe ssDNA was first immobilized onto the electrode surface using self-assembly monolayers and allowed to hybridize with the target ssDNA. The capacitance changes were measured for 35-mer homonucleotides. The self-assembly monolayer and DNA immobilization events were verified independently by contact angle measurement and FTIR. Capacitance values are measured at frequencies ranging from 75 kHz to 5 MHz, using 0 VDC bias and 25 mVAC signals. Approximately 9% change in capacitance was observed after DNA hybridization at 75 kHz.

Original languageEnglish
Pages (from-to)185-190
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
StatePublished - 2002
EventBioMEMS and Bionanotechnology - San Francisco, CA, United States
Duration: 1 Apr 20023 Apr 2002


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