Mingqian Tan,Yafeng Wang,Ziying Hong,Ping Zhou,Jie Jiang,Bin Su
Cathodic electrochemiluminescence (ECL) of a luminol (or its analogues)-dissolved oxygen (O2) system is an ideal alternative to ECL of the traditional luminol–hydrogen peroxide (H2O2) system, which can efficiently avoid the self-decomposition of H2O2 at room temperature. However, the mechanism for the generation of cathodic ECL by the luminol (or its analogues)–O2 system is still ambiguous. Herein, we report the study of cathodic ECL generation by the L012–O2 system at a glassy carbon electrode (GCE). The types of reactive oxygen species (ROS) involved generated during ECL reactions were verified. A possible reaction mechanism for the system was proposed and the rate constants of related reactions were estimated. Furthermore, several intermediates of L012 involved in the proposed pathways were validated by electrochemistry-coupled mass spectrometry. Finally, the cathodic ECL system was successfully used for measuring the antioxidant capacity of commercial juice with Trolox as a standard.
Improvement in the sensitivity and accuracy of ECL-based biosensors, to a great extent, depends on the fabrication of high-performance electrochemiluminescence (ECL) sensors. Herein, polyethyleneimine (PEI)-grafted bimetallic ZnNi metal-organic framework (ZnNi-MOF/PEI) nanospheres were synthesized to prepare a L012-based ECL immunosensor for detecting carbohydrate antigen 15-3 (CA15-3). The introduced PEI was utilized not only as a bridging element for L012 luminophore and detection antibody (Ab 2 ) immobilization but also as a co-reactant for generating the self-enhanced ZnNi-MOF/PEI-L012@Ab 2 ECL signal probe. Furthermore, Pt nanoparticle-functionalized CeO 2 nanorods (CeO 2 -Pt) featuring high-efficiency electrocatalytic properties, as a co-reaction accelerator, could catalyze H 2 O 2 to generate abundant reactive oxygen species (ROS), further augmenting the ECL signal of ZnNi-MOF/PEI-L012@Ab 2 . In the presence of CA15-3 antigen, the capture antibody (Ab 1 )-conjugated CeO 2 -Pt complex (CeO 2 -Pt@Ab 1 ) and ZnNi-MOF/PEI-L012@Ab 2 would get closer to each other, with the formation of a "signal-on" sandwich-type ECL immunosensor. The ZnNi-MOF-assisted ECL biosensor achieved a detection limit of down to 5.75✕10 -5 U mL -1 . This work shows distinguished potential for measuring low levels of biomarkers that may help in the clinical diagnosis of breast cancer.
Hydrogen peroxide (H2O2) release during blood flow is commonly provoked by the cyclic stretch and dynamic shear stress of endothelial cells and is of vital significance for maintaining vascular function. Flexible and stretchable electrochemical sensors show great capability in retrieving mechanical stimulation-induced H2O2 variation; however, cell secretions, especially electroactive constituents’ interferences, remain a big concern for sensing accuracy. Herein, we developed a stretchable electrochemiluminescence (ECL) sensor by synthesizing L012-reduced gold nanospheres and decorating them onto a polydimethylsiloxane film-supported gold nanotubes substrate (Au NTs/PDMS) to form dual gold nanostructure-modified meshwork interface. Given the specific reaction between L012 and H2O2, the as-prepared Au-L012/Au NTs/PDMS exhibited outstanding selectivity toward H2O2 quantification. Through culturing human umbilical vein endothelial cells (HUVECs), real-time monitoring of transient H2O2 release from mechanically sensitive HUVECs in stretching states was realized. This work successfully incorporated the ECL sensing model into in situ cellular sensing, therefore expanding the application mode of the ECL approach for health care and biomedical investigation.
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