The facile surface chemical modification of a single glass nanopore and its use in the nonenzymatic detection of uric acid

Abstract

A conical glass nanopore was first modified with ultrathin gold nanofilm via a simple and innovative chemical reduction of HAuCl4 on a surface-attached poly(L-histidine) monolayer in the presence of a mild reductant, NH2OH·HCl, followed by surface functionalization with 2-thiouracil, and exploited for the selective nonenzymatic detection of uric acid and especially for serum sample detection.

Surface coatings for solid-state nanopores

“…Apart from gold deposition, SAM preparation does not require specialized equipment, the monolayers can form over large surfaces and they can provide surface groups that repel molecules, interact with, or covalently link to molecules of interest. 288,292 In the context of nanopore sensing, SAMs are predominantly used for sensing specific analytes, 193,201,203,204 minimizing non-specific interactions, 188,197,200,202,208 manipulating surface charge, 192,194,[196][197][198] and adding functionality such as gating of the pore, 192,205,206 preferential transport, 194,[196][197][198][199] or enhancing the signal of plasmonic nanopores. 207,209 Charles R. Martin's group was among the first to take advantage of SAMs in nanopores by chemisorbing thiols to gold surfaces deposited onto track etched nanotubes.…”

“…In another example of engineering specific interactions on the pore surface, He et al formed a gold film on glass nanopores with ∼30 nm diameters and decorated the film by selfassembly of 2-thiouracil (2-TU). 193 Hydrogen bonding between the amide moieties of uric acid and the 2-TU surface molecules allowed for the specific detection of uric acid, a biomarker used in the diagnosis of diseases like gout, arthritis and renal disease. 293 As the authors increased the concentration of uric acid in the recording buffer, the ionic current increased to a stable value, indicating the binding of uric acid to the SAM coating.…”

“…293 As the authors increased the concentration of uric acid in the recording buffer, the ionic current increased to a stable value, indicating the binding of uric acid to the SAM coating. 193 A SAM of nitrilotriacetic acid (NTA) groups on the goldcoated walls of a nanopore enabled specific detection of Histagged proteins. 204 This SAM also shrunk the diameter by ∼6 nm and prevented nonspecific interactions between proteins and pore walls.…”

Molecular Design of Solid‐State Nanopores: Fundamental Concepts and Applications

“…Uric Acid. He et al proposed a nonenzymatic route for sensing uric acid (UA) based on the application of glass capillary‐based nanopores . Glass nanopores were preconditioned with an ultrathin Au film, deposited by electroless plating, followed by the molecular assembly 2‐thiouracil (2‐TU).…”

CVD graphene as an electrochemical sensing platform for simultaneous detection of biomolecules

“…Scurvy is caused by a deficiency of AA 5 , and abnormal DA transmission has been implicated in Huntington’s disease and neuroendocrine disorders 6 . Abnormalities in UA levels indicate symptoms of gout, hyperuricemia, and leukemia 7 , 8 ; Trp is an essential amino acid and that is a serotonin precursor, Parkinson’s disease linked to Trp 9 ; is an important precursor in the formation of N-nitrosamines, many of which have been shown to be potent carcinogens in humans 10 – 12 . AA, DA, UA, Trp, and usually coexist in body fluids 13 , 14 .…”