Hollow Double-Shell CuCo₂O₄@Cu₂O Heterostructures as a Highly Efficient Coreaction Accelerator for Amplifying NIR Electrochemiluminescence of Gold Nanoclusters in Immunoassay

Abstract

The evolution of electrochemiluminescence (ECL) emission amplified by coreaction accelerator in near-infrared (NIR) area has been overwhelmingly anticipated for ultrasensitive detection of disease biomarkers. Herein, the hollow double-shell CuCo 2 O 4 @Cu 2 O (HDS-CuCo 2 O 4 @Cu 2 O) heterostructures were conveniently prepared and utilized as an attractive coreaction accelerator to improve the NIR ECL performance of gold nanoclusters (AuNCs) for the first time. Benefiting from perfectmatched lattice spacing, unique Cu 2 O nanoparticles (NPs) were formed in situ on the layered-hollow CuCo 2 O 4 nanospheres (NSs) to obtain HDS-CuCo 2 O 4 @Cu 2 O heterostructures. The formed heterojunctions supplied shorter charge transfer distance and better interfacial charge transfer efficiency as well as more effective separation performance. Consequently, HDS-CuCo 2 O 4 @Cu 2 O heterostructures as an admirable electroactive substrate could significantly promote the formation of sufficient coreactant intermediate radicals to react with AuNCs cationic radicals, realizing about 3-folds stronger NIR ECL response than that of individual AuNCs. In addition, the AuNCs templated by L-methionine (L-Met) exhibited NIR ECL emission around 830 nm, which could decrease the photochemical damage to even realize a nondestructive detection with improved susceptibility and circumambient adaptability. Subsequently, a well site-oriented fixation strategy utilizing HWRGWVC heptapeptide as the specific antibody immobilizer was introduced to further preserve the bioactivity of antibody on the HDS-CuCo 2 O 4 @Cu 2 O and AuNCs surface along with enhancing the incubation performance markedly. In view of the progressive sensing mechanism, a NIR immunosensor was obtained for the ultrasensitive analysis of CYFRA21−1, which achieved a broad linear ranging from 2 fg/mL to 50 ng/mL and a low limit of detection (LOD) of 0.67 fg/mL (S/N = 3).

Ultrasensitive Electrochemiluminescence Biosensor Based on 2D Co3O4 Nanosheets as a Coreaction Accelerator and Highly Ordered Rolling DNA Nanomachine as a Signal Amplifier for the Detection of MicroRNA

“…Luminol is an extensively studied electrochemiluminescence (ECL) luminophore due to the advantages of good water solubility, nontoxicity, and superior light-emitting yield. − However, the traditional luminol/H 2 O 2 binary system always suffered from deficient ECL efficiency because of the sluggish decomposition of coreactant H 2 O 2 into reactive oxygen species (ROS) like superoxide radicals (O 2 •– ) and hydroxyl radicals (OH • ). − Recently, nanomaterials of changeable valence metal cobalt (Co), such as CuCo 2 O 4 @Cu 2 O and Co-2-MI-ZnTCPP, were adopted as coreaction accelerators of H 2 O 2 for enhancing the ECL emission because the mutual conversion of the Co 2+ /Co 3+ redox pair could efficiently excite the generation of electron holes, and then react with the molecular orbital of H 2 O 2 for promoting its decomposition. Nevertheless, the active sites of CuCo 2 O 4 @Cu 2 O and Co-2-MI-ZnTCPP are rare and hidden inside the large three-dimensional structure and thus are difficult to realize the mutual conversion of Co 2+ /Co 3+ , severely restricting further enhancement of ECL efficiency.…”

Electrochemiluminescence Systems for the Detection of Biomarkers: Strategical and Technological Advances

“…As NIR emissions have a lower background interference, cause less photochemical damage, and have a deeper tissue penetration, NIR-ECL systems have become powerful analytical tools in biomedical and diagnostic fields. The Ru (II) complex [ 61 , 62 ], QDs [ 63 , 64 ], metal NCs [ 41 , 47 , 48 , 49 , 65 , 66 ], nanocrystals [ 46 , 50 ], and perylene diimide [ 67 ] have all been used as NIR-ECL emitters. Tetraphenylenthylene (TPE) NC was synthesised and applied to the aggregation-induced ECL emission method [ 46 ].…”

“…Upon exposure to the target, CA125 was captured with specific antibodies and sequentially bound to AgInS 2 /ZnS-labelled antibodies in a sandwich-type ELISA, resulting in an ECL emission. Another example reported the use of AuNC with hollow double-shell (HDS) CuCo 2 O 4 @Cu 2 O heterostructures as a co-reaction accelerator in order to detect the cancer marker CYFRA21−1 ( Figure 2 D) [ 41 ]. In order to detect the biomarkers, GCE was functionalised with HDS-CuCo 2 O 4 @Cu 2 O, which was fused with heptapeptides (HWRGWVC; HWR) capable of binding specifically with the Fc region of the antibodies for a site-specific antibody immobilisation on the substrate.…”

“…( C ) miRNA-141 detection system combined with multiple ECL-RET reactions and a Pb 2+ -dependent DNAzyme-assisted target-recycling amplification (reprinted with permission from [ 38 ], © 2020, Elsevier). ( D ) Alpha-fetoprotein antigen (AFP) detection system using CuNCs as a near-infrared (NIR)-ECL luminophore and K 2 S 2 O 8 as a co-reactant (reprinted with permission from [ 41 ], © 2022, American Chemical Society). CVD, chemical vapour deposition; HP, hollow porous; GCE, glassy carbon electrode; BSA, bovine serum albumin; THMS, triple-helix molecular switch; NF, nanoflower; QD, quantum dot; MB, magnetic bead; GCE, glassy carbon electrode; EDC, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride; NHS, N-hydroxysuccinimide; HWR, Fc-specific heptapeptide with HWRGWVC sequence; HS, hollow sphere.…”

Cucurbituril Enhanced Electrochemiluminescence of Gold Nanoclusters via Host–Guest Recognition for Sensitive D-Dimer Sensing

“…To maintain the bioactivity of the identification element and improve the performance of the biosensor, a nonapeptide YYYHWRGWV (YYYHWR) was introduced to the surface of the NH 2 −TiO 2 and CB [7]/L-Phe/ MPA-AuNCs. The bifunctional nonapeptide cannot only be a site-oriented immobilizer to recognize the crystallizable fragment (Fc) domains of the D-dimer antibody 34 but also act as an electron donor to facilitate electron transfer via three tyrosine of the N-terminal. 35 As a result, the prepared biosensor showed admirable results in D-dimer sensing, which exhibited a linear range from 50.00 fg/mL to 100.0 ng/mL and a detection limit of 29.20 fg/mL (S/N = 3).…”