Electrochemiluminescence Resonance Energy Transfer Strategy Research Articles

Ultrasensitive Detection of SARS-CoV-2 Nucleocapsid Protein Based on Porphyrin-Based Metal-Organic Gels with Highly Efficient Electrochemiluminescence at Low Potential.

Metal-organic gels (MOGs) are a new type of intelligent soft material, which are bridged by metal ions and organic ligands through noncovalent interactions. In this paper, we prepared highly stable P-MOGs, using the classical organic electrochemiluminescence (ECL) luminescence meso-tetra(4-carboxyphenyl)porphine as the organic ligand and Fe3+ as the metal ion. Surprisingly, P-MOGs can stably output ECL signals at a low potential. We introduced P-MOGs into the ECL resonance energy transfer strategy (ECL-RET) and constructed a quenched ECL immunosensor for the detection of the SARS-CoV-2 nucleocapsid protein (SARS-CoV-2-N). In the ECL-RET system, P-MOGs were used as energy donors, and Au@Cu2O@Fe3O4 were selected as energy acceptors. The ultraviolet-visible spectrum of Au@Cu2O@Fe3O4 partially overlaps with the ECL spectrum of P-MOGs, which can effectively touch off the ECL-RET behavior between the donors and receptors. Under the ideal experimental situation, the linear detection range of the SARS-CoV-2-N concentration was 10 fg/mL to 100 ng/mL, and the limit of detection was 1.5 fg/mL. This work has broad application prospects for porphyrin-MOGs in ECL sensing.

A potential-resolved ratiometric electrochemiluminescence aptasensor for Pb2+: Gold nanoclusters and amino-terminated perylene derivative as both emitters and resonance energy transfer donor-acceptor pair

Searching for a pair of electrochemiluminescence (ECL) emitters that can be simultaneously applied as energy donor-acceptor pair is very vital for ECL resonance energy transfer strategy (ECL-RET)-based ratiometric ECL aptasensors, as it can avoid the complex design caused by the addition of exogenous donor or acceptor. Herein, gold nanoclusters (AuNCs) with aggregation-induced emission property and amino-terminated perylene derivative (PTC-NH2) with a broad absorption range were firstly combined to generate the anodic and cathodic ECL signals, respectively. Importantly, they were also operated as a novel ECL-RET donor-acceptor pair due to their favorable spectral overlap. On this basis, a potential-resolved ratiometric ECL aptasensor was established to detect lead ions (Pb2+). Specifically, the energy of AuNCs was absorbed by PTC-NH2 in the absence of Pb2+, leading to a decrease of the anodic ECL signal and the appearance of the cathodic ECL signal. Upon the addition of Pb2+, the ECL-RET process was impeded, and the ECL signals were reversed. By measuring the ratio of AuNCs and PTC-NH2 ECL intensities, the developed ratiometric ECL aptasensor displayed a low detection limit of 0.05 pM with excellent selectivity and satisfactory stability. Finally, the proposed aptasensor presented favorable feasibility for Pb2+ assays in soil samples.

A potential-resolved electrochemiluminescence resonance energy transfer strategy for the simultaneous detection of neuron-specific enolase and the cytokeratin 19 fragment.

An electrochemiluminescence resonance energy transfer (ECL-RET) immunosensor was developed based on the potential-resolved technology for the simultaneous detection of neuron-specific enolase (NSE) and the cytokeratin 19 fragment (CYFRA21-1). The absorption spectrum of gold nanorods (AuNRs) perfectly overlapped with the ECL spectra of SnS2@Pt and Ru(bpy)32+/Zn-MOF, so they exhibited an excellent ECL-RET effect with high efficiency. Zn-MOF possesses a large surface area, which allows for the loading of Ru(bpy)32+. This results in a signal probe of Ru(bpy)32+/Zn-MOF/Ab1 showing a strong ECL emission. Simultaneously, owing to the excellent electronic conductivity of PtNPs, they can increase the electron transfer rate between S2O82- and tin disulfide nanoflowers (SnS2NFs). Hence, the ECL signal of SnS2NFs can be enhanced. Under the optimal conditions, the linear range for NSE is 0.2 pg mL-1-20 ng mL-1 with a detection limit of 79 fg mL-1. The linear range for CYFRA21-1 is 1.25 pg mL-1-12.5 ng mL-1 with a detection limit of 0.43 pg mL-1. The proposed immunosensor can be used for the sensitive simultaneous detection of NSE and CYFRA21-1 in human serum and has promise for clinical diagnostics.

Electrochemiluminescence Double Quenching System Based on Novel Emitter GdPO4:Eu with Low-Excited Positive Potential for Ultrasensitive Procalcitonin Detection.

Nowadays, the electrochemiluminescence (ECL) immunosensor with the unique superiority of tunable luminescence and ultrahigh sensitivity has become one of the most promising immunoassay techniques, especially for low-abundance biomarkers analysis. However, the use of signal probes with high excited potential and applied emitters which owned good intensity but biotoxicity limited its application. Herein, an ECL resonance energy transfer strategy was developed based on protein bioactivity protection utilizing europium-doped phosphoric acid gadolinium (GdPO4:Eu) as novel low-potential luminophor (donor) and Pd@Cu2O as the quenching probe (acceptor). Specifically, GdPO4:Eu was first prepared by using the hydrothermal synthesis method to apply in ECL, and when it coexisted with K2S2O8, cathode, a strong ECL signal would be generated at a low potential of -1.15 V (vs Ag/AgCl), where the immunocompetence of antigens and antibodies can be maintained well. Electrical pair Eu3+/Eu2+, as the coreactant promoter, produced by potential excitation could produce more SO4•- to accelerate the oxidation process of GdPO4:Eu. Meanwhile, Cu2O coated onto Pd (Pd@Cu2O), as a dual-quencher, enhanced the quenching effect of Pd alone and controlled the ECL intensity of the "signal on" state within a reasonable range. As a result, the proposed biosensor for detection of trace procalcitonin, a biomarker of systemic inflammatory response syndrome, exhibited a far low detection limit, 0.402 fg/mL (S/N = 3). Importantly, this work not only utilized a promising ECL emitter for biosensing platform construction but also had momentous potential in biomarker detection of disease diagnosis and clinical analysis.

DNA nanomachine-based regenerated sensing platform: a novel electrochemiluminescence resonance energy transfer strategy for ultra-high sensitive detection of microRNA from cancer cells.

The construction of DNA nanomachines holds great significance in the development of DNA nanostructures; however, the real application of nanomachines is still in its early stage. Moreover, one-step regenerated sensing platforms for the detection of biomarkers in the current research remain a practical challenge. Herein, a novel electrochemiluminescence resonance energy transfer (ERET) strategy between Alexa Flour 488 (AF 488), which is a type of small molecule dye, as the donor and CdSe@ZnS quantum dots (QDs) as the acceptor, which easily enter the cells, has been reported and was applied for the construction of a DNA nanomachine-based regenerated biosensor for the ultra-high sensitive determination of cancer cells without any enzyme. First, a dual amplification strategy, including target recycling and signal transformation, was employed to achieve the conversion of a small number of miRNAs into a large amount of universal DNA reporters. Initially, the DNA tweezer was kept in the "off" state with two arms labeled with QDs and AF488, respectively. Second, in the presence of DNA reporters, the tweezer transformed to the "on" state through the hybridization of the reporter DNA and exposed the arms of the tweezer. Simultaneously, QDs and AF488 on the two arms were close enough to generate ERET, which remarkably increased the ECL intensity of the QDs. Impressively, the sensor could be regenerated by a one-step strand displacement and could be cycled for more than seven times. Owing to the dual amplification strategy and the high efficiency of the ERET between the QDs and AF488, the proposed biosensor performs in the linear range from 10 pM to 0.1 fM with a detection limit of 0.03 fM for miRNA determination, and the monitoring of different cancer cells was also achieved. Moreover, the elaborated biosensor can also realize the sensitive detection of Pb2+, which indicates that it can be potentially used for field environmental analysis and monitoring, thus offering a new modular platform for the construction of functional DNA nanomachines in the ultra-high sensitive analysis of promising biomarkers and toxic metals.