Label-free dual sensing of DNA molecules using GaN nanowires

Chin Pei Chen, Abhijit Ganguly, Chen Hao Wang, Chih Wei Hsu, Surojit Chattopadhyay, Yu Kuei Hsu, Ying Chih Chang, Kuei Hsien Chen*, Li Chyong Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations


We demonstrate a rationale for using GaN nanowires (GaNNWs) in label-free DNA-sensing using dual routes of electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) measurements, employing a popular target DNA with anthrax lethal factor (LF) sequence. The in situ EIS reveals that both high surface area and surface band-bending in the nanowires, providing more binding sites and surface-enhanced charge transfer, respectively, are responsible for the enhanced sensitivity to surface-immobilized DNA molecules. The net electron-transfer resistance can be readily deconvoluted into two components because of the coexistence of two interfaces, GaN/DNA and DNA/electrolyte interfaces, in series. Interestingly, the former, decreasing with LF concentration (CLF), serves as a signature for the extent of hybridization, while the latter as a fingerprint for DNA modification. For PL-sensing, the band-edge emission of GaNNWs serves as a parameter for DNA modification, which quenches exponentially with CLF as the incident light is increasingly blocked from reaching the core nanowire by rapidly developing a UV-absorbing DNA sheath at high CLF. Furthermore, successful application for detection of "hotspot" mutations, related to the human p53 tumor-suppressor gene, revealed excellent selectivity and specificity, down to picomolar concentration, even in the current unoptimized sensor design/condition, and in the presence of mutations and noncomplementary strands, suggesting the potential pragmatic application in complex clinical samples.

Original languageEnglish
Pages (from-to)36-42
Number of pages7
JournalAnalytical chemistry
Issue number1
StatePublished - 1 Jan 2009


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