A glass nanopore ionic sensor for surface charge analysis

Surface charge-based nanopore characterization techniques unfold unique properties and provide a powerful platform for a variety of sensing applications. In this paper, we have proposed a nanoconfined inner wall surface charge characterization method with glass nanopores. The glass nanopores were functionalized with DNA aptamers that were designed for mercury (Hg(2+)) ion immobilization by forming thymine–Hg(2+)–thymine structures. The surface charge of the nanopores was modulated by surface chemistry and Hg(2+) ion concentrations and analysed by combining zeta potential measurements on glass slides and the ionic current rectification ratio of the nanopores. Also, 1 pM Hg(2+) ions could be detected by the nanopores.