Surface Defect-Involved and Single-Color Electrochemiluminescence of Gold Nanoclusters for Immunoassay

Abstract

Single-color electrochemiluminescence (ECL) of nanoparticles is normally achieved in a bandgap engineered route via passivating the nanoparticle surface. Herein, when linear mercaptoalkanoic acids are employed as the thiolcapping agent of unary Au nanoclusters (NCs), a single-stabilizer-capped strategy is proposed to achieve surface defect-involved and single-color ECL from the AuNCs with hydrazine (N 2 H 4 ) as the coreactant. The carbon skeleton of the linear mercaptoalkanoic acids exhibits important effects on the ECL of the AuNCs, and efficient oxidative−reductive ECL is achieved with 8-mercaptooctanoic acid (MOA), 11-mercaptoundecanoic acid (MUA), and 12-mercaptododecanoic acid (MDA) capped AuNCs, respectively. The ECL of these AuNCs not only exhibits similar ECL intensity−potential profiles with the same maximum emission potential of ∼1.20 V (vs Ag/AgCl), but also demonstrates almost identical spectral ECL profiles of the same maximum emission wavelength around 713 nm as well as the same fwhm of 64 nm. The ECL of AuNCs/N 2 H 4 is obviously red-shifted to the photoluminescence of AuNCs, which not only provides unambiguous evidence that bandgap-engineered ECL of these AuNCs is quenched but also manifests that the capping agent of linear mercaptoalkanoic acid is promising for the achievement of surface defect-involved and single-color ECL from AuNCs. The MUA capped AuNCs can be utilized as an ECL tag for a sensitive and selective immunoassay, which exhibits a broad linear range from 0.5 mU/mL to 1 U/mL with a low limit of detection of 0.1 mU/mL (S/N = 3) with CA125 as the model analyte. This work provides a promising alternative to the traditional surface-passivating strategy for the achievement of single-color ECL from nanoparticle luminophores.

Surface-Defect-Involved and Eye-Visible Electrochemiluminescence of Unary Copper Nanoclusters for Immunoassay

“…The effects of coreactants on ECLs of Cys-CuNCs are investigated. According to Figure A, TPrA enables Cys-CuNCs with much stronger ECLs than the other coreactants, such as 2-(dibutylamino)­ethanol (DBAE), , triethylamine (TEA), triethanolamine (TEOA), hydrazine hydrate (N 2 H 4 ), , and hydrogen peroxide (H 2 O 2 ). , Cys-CuNCs/DBAE exhibits two ECL processes around +0.88 and +1.19 V (curve b), which are much weaker than those of Cys-CuNCs/TPrA, respectively (curve a). Cys-CuNCs/TEA and Cys-CuNCs/TEOA only exhibit one weak ECL process around +1.15 V (curves c and d).…”

“…Cys CuNCs e 0.85 V (3) 53,54 triethylamine (TEA), 55 triethanolamine (TEOA), 39 hydrazine hydrate (N 2 H 4 ), 35,41 and hydrogen peroxide (H 2 O 2 ). 56,57 Cys-CuNCs/DBAE exhibits two ECL processes around +0.…”

“…33,34 To the best of our knowledge, although only very limited unary metal NCs, such AuNCs, can be highly passivated to give off bandgap-engineered ECL of a single color, 9 some investigation has provided unambiguous evidence that single-color ECL can be conveniently achieved from metal NC luminophores via completely blocking the bandgap-engineered route. 9,15,35 The unary metal NCs with single-color ECLs in the surface-defect- involved route might provide an alternative to molecular ECL luminophores for ECL evolution. 8,33,36−38 39 Zhai et al designed a doping growth strategy to prepare BSA-capped Au−Ag bimetallic NCs with surface-defectinvolved and single-color ECL around 794 nm.…”

“…Unary metal NCs are a kind of NPs of a few to several tens atoms; − their low or nontoxicities and high biocompatibilities are promising to develop and design toxic-element-free ECL luminophores. , To the best of our knowledge, although only very limited unary metal NCs, such AuNCs, can be highly passivated to give off bandgap-engineered ECL of a single color, some investigation has provided unambiguous evidence that single-color ECL can be conveniently achieved from metal NC luminophores via completely blocking the bandgap-engineered route. ,, The unary metal NCs with single-color ECLs in the surface-defect-involved route might provide an alternative to molecular ECL luminophores for ECL evolution. ,,− Jia et al proposed a dual-stabilizer-capped strategy to synthesize AuNCs with single-color and surface-defect-involved ECL around 860 nm . Zhai et al designed a doping growth strategy to prepare BSA-capped Au–Ag bimetallic NCs with surface-defect-involved and single-color ECL around 794 nm .…”

Electrochemiluminescence biosensor for cardiac troponin I with signal amplification based on a MoS2@Cu2O–Ag-modified electrode and Ce:ZnO-NGQDs

“…9,10 So far, it has been widely used in immunoassays. [11][12][13][14] Our work focuses on building a sandwiched ECL sensor to detect cTnI at ultrasensitive levels.…”