Local solid-state modification of nanopore surface charges

TL;DR

This paper demonstrates a method to modify and tune the surface charges of solid-state nanopores using electron beam induced deposition (EBID) with silicon oxide, providing a stable and accessible alternative to high-energy fabrication techniques.

Contribution

The authors introduce a simple, accessible technique using standard micromachining and EBID to modify nanopore surface charges, avoiding damage from traditional high-energy methods.

Findings

EBID can effectively tune nanopore surface charge.

Surface charge remains stable across various concentrations.

The method is compatible with common fabrication techniques.

Abstract

The last decade, nanopores have emerged as a new and interesting tool for the study of biological macromolecules like proteins and DNA. While biological pores, especially alpha-hemolysin, have been promising for the detection of DNA, their poor chemical stability limits their use. For this reason, researchers are trying to mimic their behaviour using more stable, solid-state nanopores. The most successful tools to fabricate such nanopores use high energy electron or ions beams to drill or reshape holes in very thin membranes. While the resolution of these methods can be very good, they require tools that are not commonly available and tend to damage and charge the nanopore surface. In this work, we show nanopores that have been fabricated using standard micromachning techniques together with EBID, and present a simple model that is used to estimate the surface charge. The results show that EBID with a silicon oxide precursor can be used to tune the nanopore surface and that the surface charge is stable over a wide range of concentrations.