Cross Disjoint Mortise Confined Solid-State Nanopores for Single-Molecule Detection

Solid-state nanopores have attracted widespread attention in the single-molecule detection application. However, getting controllable nanopores with high sensitivity and robustness requires a revolutionary breakthrough in nanopore fabrication. As a convenient and low-cost nanopore fabrication method, the controlled dielectric breakdown technology can hardly control the position and number of nanopores. This work proposes a concept of cross disjoint mortise confined solid-state nanopore (CDM-Nanopore) fabricated using a focused gallium ion beam and controlled dielectric breakdown technologies. A confined domain formed by the two cross disjoint mortise structures localizes the position for nanopore fabrication with a controlled dielectric breakdown method. The ion translocation analyses and noise performance of CDM-Nanopore were experimentally demonstrated with excellent sensitivities for long-term molecular detection due to their robustness and low noise characteristics of cross disjoint mortise structures. The surface charges have a great effect on the capture rate for DNA translocation in the confined nanopore while adding the formamide into G-quadruplex translocation experimentally. Besides, the COMSOL simulation results verify that the CDM-Nanopore has the same electrical properties as the conventional nanopore with the same effective thickness. These provide insight into an understanding of DNA translocation in the CDM-Nanopore to enable the localized nanopore fabrication with the controlled dielectric breakdown technology. Our results can be used to expand the membrane nanopores to zero-depth nanopores for molecular sensing and DNA/RNA sequencing.