Biomimetic nanopore for sensitive and selective detection of Hg(ii) in conjunction with single-walled carbon nanotubes

Abstract

In this article, we propose a new method for selective detection of Hg²⁺ based on a biomimetic nanopore sensing platform in combination with single-walled carbon nanotubes (SWNTs). As is well known, folded DNA in the presence of Hg²⁺ can be separated from single-stranded DNA through SWNTs, and the folded DNA can be quantitated with cone-shaped nanopore whose surface was coated by polyethyleneimine (PEI)/Zr⁴⁺. Both sensitivity and selectivity based on this paradigm can be guaranteed without immobilization of probes on the nanopore surface. This approach can warrant the detection limit for Hg²⁺ down to 8.3 nM (S/N = 3) with high selectivity against other metal ions. Moreover, the application of the sensor for lake water shows that the proposed method works well for real samples. This research demonstrates an alternative approach to detect targets of interest that holds high prospects for detecting other biomolecules or metal ions in the near future.