G-quadruplex-hemin DNAzyme functionalized nanopipettes: Fabrication and sensing application.

Solid-nanopores/nanopipettes have the exquisite ability to reveal the changes in molecular volume due to the advantages of adjustable size, good rigidity and low noise. Herein, a new platform for sensing application was established based on G-quadruplex-hemin DNAzyme (GQH) functionalized gold-coated nanopipettes. In this method, GQH was immobilized on gold-coated nanopipette, which could be used as a catalyst for the reaction of H 2 O 2 with 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) to promote the conversion of ABTS to ABTS+ ions inside gold-coated nanopipette, and the change of transmembrane ion current could be monitored in real time. At the optimal conditions, there was a correlation between the ion current and the concentration of H 2 O 2 in a certain range, which could be used for the hydrogen peroxide sensing. The GQH immobilized nanopipette provides a useful platform to investigate enzymatic catalysis in confined environment, which can be used in electrocatalysis, sensing and fundamental electrochemistry. [Display omitted] • GQH-functionalized gold-coated nanopipettes was fabricated successfully. • GQH-functionalized nanopipettes was used as a catalyst for H 2 O 2 and ABTS reaction. • The conversion of ABTS to ABTS + ions resulted the change of ICR. • A H 2 O 2 sensor was established using the GQH-functionalized nanopipettes platform. [ABSTRACT FROM AUTHOR]