NANO.IL.

Single Molecule Optical DNA Sensing Using Solid-State Nanopores

Tal Gilboa Biomedical engineering, The Technion – Israel Institute of Technology, Haifa, Israel

Nanopores are single-molecule biosensors that could be used to monitor individual DNA molecules in minute quantities for the purpose of personalized diagnostics. To date, most of the work involved measurements of temporal changes in the ionic current caused by the passage of charged molecules through the nanometeric pore. Here we complement the electrical measurements in solid state nanopores with high-sensitivity optical detection in order to detect specific features on the molecule as it translocates through the pore1. This characterization technique is based on labeling specific regions of diagnostic importance with fluorescent dyes, identifying the color sequence as the molecule translocate through the pore, and classifying the molecule according to the optical signal obtained. One possible application of this sensing platform is quantification of the number of unmethylated CpGs in the DNA target sequences2. In this case, each DNA molecule is first labeled using a single step covalent coupling with synthetic AdoMet analogues and DNA methyltransferases (MTases), and then analyzed using electro-optical nanopore detection and quantification with a single or multiple colors2. Furthermore, we combine the unique molecular-focusing capability of a solid-state nanopore with a plasmonic nanowell structure to achieve localized fluorescence enhancement of the labeled DNA molecules as they translocate through a nanopore. The stacked plasmonic nanowell-nanopore biosensor suppresses almost entirely the background fluorescence and yields net >10 fold enhancement of the fluorescence intensity, offering an extremely high S/B ratio for single-molecule detection at minimal laser excitation while maintaining sub-ms resolution3.

References:

  1. Gilboa, T. and A. Meller, Optical sensing and analyte manipulation in solid-state nanopores. Analyst,
  2. Gilboa, T.; Chen Torfstein, C.; Juhasz, M.; Grunwald, A.; Ebenstein, Y.; Weinhold, E.; Meller A. DNA methylation quantification using electro-optical sensing in solid-state nanopores. ACS Nano, 2016
  3. Assad, O. N.; Gilboa, T.; Spitzberg, J.; Juhasz, M.; Weinhold, E.; Meller, A. Light-Enhancing Plasmonic-Nanopore Biosensor for Superior Single-Molecule Detection. Adv. Mater. 2016








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