Sapphire-supported nanopores for low-noise DNA sensing

Pengkun Xia, Jiawei Zuo, Pravin Paudel, Shinhyuk Choi, Xiahui Chen, Md Ashiqur Rahman Laskar, Jing Bai, Weisi Song, Jong One Im, Chao Wang

Research output: Contribution to journalArticlepeer-review

Abstract

Solid-state nanopores have broad applications from single-molecule biosensing to diagnostics and sequencing. The high capacitive noise from conventionally used conductive silicon substrates, however, has seriously limited both their sensing accuracy and recording speed. A new approach is proposed here for forming nanopore membranes on insulating sapphire wafers to promote low-noise nanopore sensing. Anisotropic wet etching of sapphire through micro-patterned triangular masks is used to demonstrate the feasibility of scalable formation of small (<25 μm) membranes with a size deviation of less than 7 μm over two 2-inch wafers. For validation, a sapphire-supported (SaS) nanopore chip with a 100 times larger membrane area than conventional nanopores was tested, which showed 130 times smaller capacitance (10 pF) and 2.6 times smaller root-mean-square (RMS) noise current (18–21 pA over 100 kHz bandwidth, with 50–150 mV bias) when compared to a silicon-supported (SiS) nanopore (~1.3 nF, and 46–51 pA RMS noise). Tested with 1k base-pair double-stranded DNA, the SaS nanopore enabled sensing at microsecond speed with a signal-to-noise ratio of 21, compared to 11 from a SiS nanopore. This SaS nanopore presents a manufacturable nanoelectronic platform feasible for high-speed and low-noise sensing of a variety of biomolecules.

Original languageEnglish (US)
Article number112829
JournalBiosensors and Bioelectronics
Volume174
DOIs
StatePublished - Feb 15 2021
Externally publishedYes

Keywords

  • DNA sensing
  • Low capacitance
  • Low noise
  • Sapphire etching
  • Scalable membrane fabrication
  • Signal-to-noise ratio

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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