Label-free quantitative DNA detection using the liquid core optical ring resonator

Jonathan D. Suter, Ian M. White, Hongying Zhu, Huidong Shi, Charles W. Caldwell, Xudong Fan

Research output: Contribution to journalArticlepeer-review

145 Scopus citations


We demonstrated quantitative real-time label-free detection of DNA sequences using the liquid core optical ring resonator (LCORR) sensor. The LCORR is a recently developed sensing platform that integrates microfluidics and photonic sensing technology with low detection limit and sub-nanoliter detection volume. We analyzed experimentally and theoretically the LCORR response to a variety of DNA samples that had different strand lengths (25-100 bases), number of base- mismatches (1-5), and concentrations (10 pM to 10 μM) to evaluate the LCORR sequence detection capability. In particular, we established the linear correlation between the LCORR sensing signal and the molecule density, which allows us to accurately calculate the molecule density on the surface. It is found that the probe surface coverage was 26-51% and the extent of hybridization was 40-50%. The titration curve for 25-base probe and 25-base target DNA yields a dissociation constant of 2.9 nM. With a 37.1 nm/RIU LCORR, detection of 10 pM bulk DNA concentration was demonstrated. The mass detection limit was estimated to be 4 pg/mm2, corresponding to a density of 1010 molecules/cm2 on the surface. We also showed that the LCORR was sensitive enough to differentiate DNA with only a few base-mismatches based on the raw sensing signal and kinetic analysis. Our work will provide important insight into the light-DNA interaction at the ring resonator surface and lay a foundation for future LCORR-based DNA label-free microarray development.

Original languageEnglish (US)
Pages (from-to)1003-1009
Number of pages7
JournalBiosensors and Bioelectronics
Issue number7
StatePublished - Feb 28 2008
Externally publishedYes


  • DNA detection
  • Label-free
  • Microfluidics
  • Optical ring resonator
  • Refractometric detection

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry


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