Electrical sensing of DNA-hybridization using two-port network based on suspended carbon nanotube membrane

An approach was presented for electrical sensing of deoxyribonucleic acid (DNA)-hybridization in solution using a two-port network based on single-walled suspended carbon nanotube (SWCNT) membrane. A single stranded probe DNA (5'-NH2-(CH2)6-CGC CGA TTG GAC AAA ACT TAA A-3') was immobilized on the SWCNT membrane. A solution with the complementary single stranded DNA (D'FITC: 5'-FITC-T TTA AGT TTT GTC CAA TCG GCG-3') in various concentrations was then dropped on the membrane. The two-port network composed of the suspended SWCNT membrane and its underneath gate were characterized by coupling with a vector network analyzer. The resonance frequency of transmission coefficient S21 was observed to be around 10 MHz. The resonance frequency shifts with DNA-hybridization, and the sensing limit was approximately 50 nM. The advantages of this approach include low-noise frequency output, solution based real time detection and capable of on-chip integration, etc.