Suter Jonathan D, White Ian M, Zhu Hongying, Shi Huidong, Caldwell Charles W, Fan Xudong
Department of Biological Engineering, 240D Bond Life Sciences Center, University of Missouri-Columbia, Columbia, MO 65211, USA.
Biosens Bioelectron. 2008 Feb 28;23(7):1003-9. doi: 10.1016/j.bios.2007.10.005. Epub 2007 Oct 22.
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 microM) 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/mm(2), corresponding to a density of 10(10) molecules/cm(2) 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.
我们展示了使用液芯光环谐振器（LCORR）传感器对DNA序列进行定量实时无标记检测。LCORR是一个最近开发的传感平台，它将微流控技术和光子传感技术集成在一起，具有低检测限和亚纳升检测体积。我们通过实验和理论分析了LCORR对各种具有不同链长（25 - 100个碱基）、碱基错配数（1 - 5个）和浓度（10 pM至10 microM）的DNA样品的响应，以评估LCORR的序列检测能力。特别地，我们建立了LCORR传感信号与分子密度之间的线性相关性，这使我们能够准确计算表面的分子密度。结果发现探针表面覆盖率为26 - 51%，杂交程度为40 - 50%。25碱基探针和25碱基靶DNA的滴定曲线得出解离常数为2.9 nM。使用37.1 nm/RIU的LCORR，证明了能够检测10 pM的本体DNA浓度。质量检测限估计为4 pg/mm(2)，对应于表面密度为10(10)个分子/cm(2)。我们还表明，基于原始传感信号和动力学分析，LCORR足够灵敏，能够区分仅存在少数碱基错配的DNA。我们的工作将为环形谐振器表面的光 - DNA相互作用提供重要见解，并为未来基于LCORR的无标记DNA微阵列开发奠定基础。
