Electrocheluminescence (ECL) immunoassay amplified by coreaction accelerators has experienced major breakthroughs in ultrasensitive detection of biomarkers. Herein, CeO2/SnS2 heterostructures were synthesized and applied as a novel coreaction accelerator to enhance the ECL efficiency of the luminol–dissolved O2 system for the first time. Benefiting from the well-matched lattice spacing, ultrafine CeO2 nanoparticles (NPs) were grown in situ on layered SnS2 nanosheets (NSs) with improved dispersion. CeO2/SnS2 as an electroactive substrate can remarkably accelerate the generation of abundant superoxide anion radicals (O2 •–) to react with luminol anion radical (L•–), achieving about 2-fold stronger ECL intensity than that of pure CeO2 NPs. To avoid harsh chemical synthesis of conventional ECL labels and simplify the antibody conjugation process, ferritin (Ft) was served as a natural nanocarrier to immobilize luminol molecules (Lum@Ft) via a one-step linkage, whose protein nanocage can easily connect with the detection antibody. Moreover, a robust site-oriented immobilization strategy using HWRGWVC heptapeptide as specific capturer was further adopted to maintain the bioactivity of the capture antibody on the amine-functionalized CeO2/SnS2 surface, which promoted the incubation efficiency markedly. On account of this advanced sensing strategy, a brand new biosensor was constructed for the accurate detection of heart failure biomarkers, which performed with favorable linearity in the range of 0.0001–50 ng/mL and achieved the detection limit of 36 fg/mL.
The expansion of electrochemiluminescence (ECL) technology to immunoassay at the core of care emphasizes all immune molecules will not be inactivated in the analysis process. That poses a major challenge to ECL-based biosensors due to the deoxynucleotide sequences of an antigen or antibody could be oxidized through a route of excessive cyclic potential. Herein, an ultrasensitive ECL biosensor was developed based on a novel bioactivity-protected sensing strategy utilizing Au nanoclusters (Au NCs) as low-potential luminophor for detection of procalcitonin (PCT). Bovine serum albumin (BSA)-templated Au NCs exhibited a low-potential anodic ECL signal in triethylamine (TEA) solution at 0.87 V, where it is suitable for the survival of immune molecules. Taking advantage of good conductivity and high surface area, a Cu2S snowflake not only functions as a satisfying substrate for connecting immune molecules but also acts as co-reaction accelerator to produce more cationic radicals TEA•+, which could improve the ECL intensity needed to meet the requirements of trace analysis. Otherwise, HWRGWVC (HC-7) heptapeptide as specific antibody immobilizer for site-oriented fixation was introduced to further maintain the bioactivity of an antibody. In view of the preceding discussion, the obtained biosensor exhibited ultrahigh immune recognition to targets so that the detection limit was as low as an unprecedented value of 2.36 fg/mL, which will be of great significance to the application and development of a biosensor in the future.
The theory of aggregation-induced electrochemiluminescence (AIECL) has introduced new vitality into preparing new electrochemiluminescence (ECL) emitters. However, the progress in the application of biosensing analysis has been slow owing to the lack of AIECL-based functional nanomaterials. Herein, a biosensor was fabricated using mesoporous silica nanosphere (MSN) matrix-confined 1,1,2,2-tetra(4carboxylphenyl)ethylene (TPE) as a well-ordered ECL emitter and selfdesigned WHPWSYC (WC-7) heptapeptide as the target capturer for CD44 detection. TPE and its co-reactant, triethylamine (TEA), were encapsulated in the MSN nanomatrix to enhance the radiation transition by limiting the intramolecular rotation of TPE molecule benefit from the spatial confinement effect, and the ECL intensity is self-enhanced by replacing electron free diffusion in the conventional ECL system. MSN−TPE−TEA can act as satisfactory sensing substrates that improve the reproducibility and batch-to-batch consistency of biosensors and functions as a stable signal label for trace analysis of biomarkers. As a substitute for antibody and hyaluronic acid, the WC-7 heptapeptide significantly reduced the steric hindrance of the sensing interface in CD44 affinity tests. Combined with the DNA strand displacement reaction, this strategy shows a good ECL response to standard CD44 antigen and MCF-7 cells with different concentrations, which is another feasible method for detecting CD44 in body fluids or living cells.
This work outlines a versatile and high-performance electrochemiluminescence (ECL) platform that uses complex luminescent molecules [Ru(II) complex] formed by carbohydrazide (CON4H6) and tris(4,4′-dicarboxylicacid-2,2′-bipyridyl)ruthenium(II) dichloride [Ru(dcbpy)3 2+] as emitters to facilitate the intramolecular ECL mechanism for reducing the response distance and interference, and they were kept immobilized on a porous bismuth vanadate nanoarray (BiVO4 NA) to improve the orderliness of electron transfer. In addition, the detection was made depending on the etching of triangular silver nanoparticles (T-Ag NPs) by self-generated hydrogen peroxide (H2O2) to initiate the recovery response of the originally quenched ECL due to ECL-RET between the Ru(II) complex (donor) and T-Ag NPs (receptor). Because of the antibacterial application of dopamine, its own redox ability could produce more H2O2 for etching receptor T-Ag NPs under near-infrared (NIR) stimulation. Notably, in this system, the specific binding of antigens and antibodies with the autogenesis process of H2O2 and the ECL detection procedure are independent. Therefore, the proposed system can avert the impact of complex biological samples effectively, and the ECL efficiency of the Ru(II) complex can be readily utilized. On this basis, a biosensor is explored for the primary diagnosis of squamous cell carcinoma by detecting the biomarker named after cytokeratin fragment 19 (CYFRA21-1), from which an excellent linearity from 0.1 pg/mL to 50 ng/mL is achieved with a detection limit of 0.058 pg/mL. All of these results confirmed that this strategy can be a promising candidate for fabricating an ECL-based biosensor.
The development of label-free electrochemiluminescence (ECL)-based sensing technology for biomarkers detection has a congenital defect compared to noncompetitive sandwich-type biosensors due to the lack of detection antibody conjugated with a signal label. Nevertheless, it is still not difficult to realize the ultrasensitive analysis benefit from the exploration of efficient sensing substrates and signal transducers. In this work, an innovative sensing system is purposed utilizing Fe2O3 nanoarrays (Fe2O3 NAs) as a well-ordered coreaction accelerator and polypeptide-biomineralized gold nanoclusters (Au NCs) as a signal transducer. Bifunctional peptide ligands of H2N-MMYYHFRRHL-COOH (MYH-10) are self-designed; it cannot only play a role of reductant and coupling reagent for cluster formation using the MMYY sequence root in the N-terminal but also act as a connection for coupling carriers and immune molecules via the HFRRHL region of the C-terminal. In addition to intramolecular ECL emission between Au NCs and tris(3-aminoethyl)amine (TAEA), all strategies undoubtedly reduce the spatial hindrance of the sensing interface and increase the effectiveness of the electron transfer and immune recognition. With CYFRA21-1 as a target, the biosensor exhibits a linear ECL response in a wide range (10 fg mL–1 to ∼100 ng mL–1) and an ultralow detection limit of 1.33 fg mL–1 (S/N = 3). With convincing experimental data, these innovative strategies will be more eye-catching in peptide-based nanocluster synthesis and expansion of a more novel thought for sensing platform fabrication.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.