Label‐Free Pyrophosphate Recognition with Functionalized Asymmetric Nanopores. Issue 15 (3rd March 2016)

• Record Type: Journal Article
• Authors: Ali, Mubarak; Ahmed, Ishtiaq; Ramirez, Patricio; Nasir, Saima; Niemeyer, Christof M.; Mafe, Salvador; Ensinger, Wolfgang
• Is Part Of: Small. Volume 12:Issue 15(2016)
• Page Start: 2014
• Page End: 2021
• Publication Date: 2016-03-03
• Subjects: current rectification -- functionalization -- sensors -- pyrophosphate, track‐etching -- Zn(II)–dipicolylamine complexes; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201600160
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract : The label‐free detection of pyrophosphate (PPi) anions with a nanofluidic sensing device based on asymmetric nanopores is demonstrated. The pore surface is functionalized with zinc complexes based on two di(2‐picolyl)amine [bis(DPA)] moieties using carbodiimide coupling chemistry. The complexation of zinc (Zn 2+ ) ion is achieved by exposing the modified pore to a solution of zinc chloride to form bis(Zn 2+ –DPA) complexes. The chemical functionalization is demonstrated by recording the changes in the observed current–voltage ( I–V ) curves before and after pore modification. The bis(Zn 2+ –DPA) complexes on the pore walls serve as recognition sites for pyrophosphate anion. The experimental results show that the proposed nanofluidic sensor has the ability to sense picomolar concentrations of PPi anion in the surrounding environment. On the contrary, it does not respond to other phosphate anions, including monohydrogen phosphate, dihydrogen phosphate, adenosine monophosphate, adenosine diphosphate, and adenosine triphosphate. The experimental results are described theoretically by using a model based on the Poisson–Nernst–Planck equations. Abstract : A nanofluidic sensor for sensing pyrophosphate (PPi) is developed by attaching bis(dipicolylamine) [bis(Zn 2+ –DPA)] onto pore surfaces. The interaction of the PPi anion with bis(Zn 2+ –DPA) moieties promotes sensitive changes in surface charges and concomitant current rectification characteristic of asymmetric nanopores.