In Situ Controllable Generation of Copper Nanoclusters Confined in a Poly-l-Cysteine Porous Film with Enhanced Electrochemiluminescence for Alkaline Phosphatase Detection

Abstract

Copper nanoclusters (Cu NCs) as emerging luminescent metal NCs are gaining increasing attention owing to the comparatively low cost and high abundance of the Cu element in nature. However, it remains challenging to manipulate the optical properties of Cu NCs. Unlike most dispersed Cu NCs, whose luminescence efficiency was restricted by nonexcited relaxation, the Cu NCs confined in a porous poly-L-cysteine (poly-L-Cys) film were generated controllably with enhanced electrochemiluminescence (ECL) by in situ electrochemical reduction. Specifically, poly-L-Cys provided a porous structure to regulate the generation of Cu NCs within its holes, which not only increased the restriction on the intramolecular vibration and rotation of the ligands but also expedited the electron transfer near the electrode surface, reflecting in an enhancement of the ECL signal and efficiency. As an application of the confined Cu NCs, an ECL biosensor with high performance was constructed skillfully for highly sensitive detection of alkaline phosphatase (ALP), which adopted Cu NCs as the ECL luminophore and poly-L-Cys as a coreaction accelerator in a novel ECL ternary system (Cu NCs/S 2 O 8 2− /poly-L-Cys). Furthermore, an ingenious target amplification based on the combination of a DNA walker and click chemistry was developed to convert ALP to DNA strands efficiently, achieving great improvement in the recognition efficiency. As a result, the biosensor had a low detection limit (9.5 × 10 −7 U•L −1 ) and a wide linear range (10 −8 −10 −2 U•L −1 ) for ALP detection, which showed great promise for the detection of non-nucleic acid targets and the diagnosis of diseases.

Development of Hollow Electrochemiluminescent Nanocubes Combined with a Multisite-Anchored DNA Nanomachine for Mycotoxin Detection

“…The bare GCE (Φ = 4 mm) was handled based on the reported approach to achieve a smooth and clean surface . Then, 12 μL of the hollow Pd-Rub-Ag@Au nanocube solution was coated onto the bare GCE to obtain the hollow Pd-Rub-Ag@Au nanocube-modified electrode (Pd-Rub-Ag@Au nanocubes/GCE).…”

“…The bare GCE (Φ = 4 mm) was handled based on the reported approach to achieve a smooth and clean surface. 21 Then, 12 μL of the hollow Pd-Rub-Ag@Au nanocube solution was coated onto the bare GCE to obtain the hollow Pd-Rub-Ag@Au nanocube-modified electrode (Pd-Rub-Ag@Au nanocubes/GCE). Subsequently, 10 μL of the solution of 2 μM quenching DNA hybridization product (C1-S1-S2) formed by annealing (as shown in the Supporting Information (SI) Section S1.1) was incubated on the resultant electrode overnight at 4 °C by a Pd−N bond to obtain C1-S1-S2/Pd-Rub-Ag@Au nanocubes/GCE.…”

DNA Technology-assisted Signal Amplification Strategies in Electrochemiluminescence Bioanalysis

“…Pan et al confined Cu nanoclusters in a porous poly-L -cysteine film via in-situ EC reduction with efficient solidstate ECL emission. The cascade of alkaline phosphatase (ALP)-initiated click chemistry and NEase (Nb.BbvcI)-powered DNA walker resulted in the release of Fc-DNA from the electrode surface, and the ECL of Cu nanoclusters was recovered for ALP detection [63].…”

MicroRNA-Triggered Deconstruction of Field-Free Spherical Nucleic Acid as an Electrochemiluminescence Biosensing Switch

“…The bare glassy carbon electrode (GCE) was first polished by alumina slurry, followed by rinsing with ethanol and ultrapure water to obtain a clean surface. 21 Afterward, the clean GCE was deposited in 2 mL of hydrogen tetrachloroaurate hydrate (HAuCl 4 , 1%) at −0.2 V for 30 s to obtain Au nanoparticle-modified electrode (AuNPs/GCE). Then, 10 μL of Rub-Pt@mSiO 2 NSs (1 mg/mL) was coated on the AuNPs/GCE and dried naturally to form a uniform film (Rub-Pt@mSiO 2 /AuNPs/GCE).…”