On-Site Unzipping of Single-Molecule DNA in a Spot-Heated Nanopore

Strand separation is a prerequisite for any genome sequencing method, including the single-molecule approach via solid-state nanopore sensing. Here, we report on the local electrical heating of nanofluidic channels for on-site denaturation to resistive pulse analysis of nucleic acids. We lithographed a Pt nanocoil around a nanopore in a SiN_x membrane. The local temperature at the pore was finely controlled by the voltage applied to the metallic nanowire for the self-heating. The capture-to-translocation motions of DNA were found to be influenced by temperature-gradient-mediated factors, including electrophoresis, viscous dragging, and thermophoresis. Most importantly, we demonstrated unzipping to single-molecule detections of pBR322 plasmid and lambda DNA in the nanopore locally heated with the nanoheater of temperature above 423 and 564 K, respectively. This device concept may be useful for solid-state nanopore sequencing of DNA and proteins.