New Signal Amplification Strategy Using Semicarbazide as Co-reaction Accelerator for Highly Sensitive Electrochemiluminescent Aptasensor Construction

Abstract

A highly sensitive electrochemiluminescent (ECL) aptasensor was constructed using semicarbazide (Sem) as co-reaction accelerator to promote the ECL reaction rate of CdTe quantum dots (CdTe QDs) and the co-reactant of peroxydisulfate (S2O8(2-)) for boosting signal amplification. The co-reaction accelerator is a species that when it is introduced into the ECL system containing luminophore and co-reactant, it can interact with co-reactant rather than luminophore to promote the ECL reaction rate of luminophore and co-reactant; thus the ECL signal is significantly amplified in comparison with that in which only luminophore and co-reactant are present. In this work, the ECL signal probes were first fabricated by alternately assembling the Sem and Au nanoparticles (AuNPs) onto the surfaces of hollow Au nanocages (AuNCs) via Au-N bond to obtain the multilayered nanomaterials of (AuNPs-Sem)n-AuNCs for immobilizing amino-terminated detection aptamer of thrombin (TBA2). Notably, the Sem with two -NH2 terminal groups could not only serve as cross-linking reagent to assemble AuNPs and AuNCs but also act as co-reaction accelerator to enhance the ECL reaction rate of CdTe QDs and S2O8(2-) for signal amplification. With the sandwich-type format, TBA2 signal probes could be trapped on the CdTe QD-based sensing interface in the presence of thrombin (TB) to achieve a considerably enhanced ECL signal in S2O8(2-) solution. As a result, the Sem in the TBA2 signal probes could accelerate the reduction of S2O8(2-) to produce the more oxidant mediators of SO4(•-), which further boosted the production of excited states of CdTe QDs to emit light. With the employment of the novel co-reaction accelerator Sem, the proposed ECL biosensor exhibited ultrahigh sensitivity to quantify the concentration of TB from 1 × 10(-7) to 1 nM with a detection limit of 0.03 fM, which demonstrated that the co-reaction accelerator could provide a simple, efficient, and low-cost approach for signal amplification and hold great potential for other ECL biosensors construction.

Electrochemiluminescence of Supramolecular Nanorods and Their Application in the “On–Off–On” Detection of Copper Ions

“…Significantly, when the PTCA‐An/GCE was measured in S 2 O 8 2− solution, the ECL signal was noticeably increased about two‐fold (Figure A, curve c) compared with that of PTCA/GCE (Figure A, curve b). Thus, we speculated that the aniline might act as a new co‐reaction accelerator in the PTCA/S 2 O 8 2− system, which was similar to the effect of semicarbazide in the CdTe QDs/S 2 O 8 2− system . Specifically, the co‐reaction accelerator of aniline is a species that could interact with co‐reactant of S 2 O 8 2− rather than the luminophore of PTCA to promote the ECL reaction rate of the luminophore and co‐reactant, resulting in enhancement of the ECL response.…”

“…Thus, we speculated that the aniline might act as an ew co-reaction accelerator in the PTCA/S 2 O 8 2À system, which was similart ot he effect of semicarbazide in the CdTe QDs/S 2 O 8 2À system. [48] Specifically,t he co-reactiona ccelerator of aniline is as peciest hat could interact with co-reactant of S 2 O 8 2À rathert han the luminophore of PTCA to promote the ECL reactionrate of the luminophoreand co-reactant, resulting in enhancement of the ECL response. Curve ci nF igure 2B shows the corresponding CV wave of PTCA-An/GCE;i tc an be seen that the reduction peak potentials hiftedn egatively and the corresponding peak currenti ncreased distinctly in comparison to that of PTCA/GCE ( Figure 2B,c urve b), indicating that the aniline could promote the oxygenation between PTCA and S 2 O 8 2À .H owever,w hen the PTCA-An/GCE was measured in PBS solution,p redictably,n oE CL signal was observedi ns amep otential range (Figure 2A,c urve d), provingt hat the aniline could not interactw ith the luminophore (PTCA) to amplify the ECL.…”

Triple Amplification of 3,4,9,10-Perylenetetracarboxylic Acid by Co2+-Based Metal–Organic Frameworks and Silver–Cysteine and Its Potential Application for Ultrasensitive Assay of Procalcitonin

“…To study a possible ECL enhancing mechanism of ZIF-67 particles and the AgCys complex, the ECL responses in various systems were measured. As illustrated in Figure A, the ECL peak of bare GCE was first detected in S 2 O 8 2– solution, which was because of the emission of singlet oxygen ( 1 (O 2 ) 2 *) (curve a) . Curve b demonstrated the ECL response of pure PTCA, which was ascribed to the emission of the PTCA excited state ( 1 PTCA*) .…”

“…As illustrated in Figure 2A, the ECL peak of bare GCE was first detected in S 2 O 8 2− solution, which was because of the emission of singlet oxygen ( 1 (O 2 ) 2 *) (curve a). 32 Curve b demonstrated the ECL response of pure PTCA, which was ascribed to the emission of the PTCA excited state ( 1 PTCA*). 33 Afterward, a further modified electrode, PTCA/ZIF-67/AgCys/GCE, was tested in a S 2 O 8 2− solution, and the results exhibited a significant enhancement of ECL intensity compared to pure PTCA (curve c).…”

Capillary Electrophoresis and Quantum Dot Electrochemiluminescence by Micellar Reversed Sweeping

“…Dong 等 [8] 通过化学氧化活性炭制备了直径 3～4 nm 的石墨烯量子点, 具有很强的电化学发光特性. Ma 等 [9] 用氨基脲作为共反应剂增强 CdTe 量子点的电化学 发 光 强 度 检 测 凝 血 酶 . Jie 等 [10] 研 究 了 树 枝 状 的 CdSe-ZnS 量子点纳米簇用于电化学发光检测肿瘤细胞.…”