RESUMEN
Herein we report electrochemiluminescence (ECL) generation from three new iridium(III)/ruthenium(II) (Ir(III)/Ru(II)) complexes with naphthyl (nap) tags in solutions and host-guest thin films. In comparison with its parent structure, the addition of a nap tag to [4-(2-naphthalenyl)-1,10-phenanthroline]bis(2,2'-bipyridine)ruthenium(II) results in a 6.1-fold enhancement in the ECL efficiency. Moreover, the nap tag enables the non-covalent immobilization of Ir(III)/Ru(II) complexes via host-guest interactions. Therefore, a molecular thin film was constructed by hydrophobic effects between the cavity of ß-cyclodextrin and the nap tags, which emits stable and strong ECL emission in the presence of tri-n-propylamine (TPrA). These results give a mechanistic insight into ECL generation from (Ir(III)/Ru(II)) complexes with host-guest recognition tags and may help in the development of host-guest thin film-based ECL sensors.
RESUMEN
One-dimensional molecular crystal waveguide (MCW) can transmit self-generated electrochemiluminescence (ECL), but heavy optical loss occurs because of the small difference in the refractive index between the crystal and its surroundings. Herein, we report a micropipette electrode-supported MCW (MPE/MCW) for precisely controlling the far-field transmission of ECL in air with a low optical loss. ECL is generated from one terminal of the MCW positioned inside the MPE, which is transmitted along the MCW to the other terminal in air. In comparison with conventional waveguides on solid substrates or in solutions, the MPE/MCW is propitious to the total internal reflection of light at the MCW/air interface, thus confining the ECL efficiently in MCW and improving the waveguide performance with an extremely low-loss coefficient of 4.49 × 10-3 dB µm-1. Moreover, by regulation of the gas atmosphere, active and passive waveguides can be resolved simultaneously inside MPE and in air. This MPE/MCW offers a unique advantage of spatially controlling and separating ECL signal readout from its generation, thus holding great promise in biosensing without or with less electrical/chemical disturbance.
RESUMEN
Developing highly sensitive multiplex immunoassays is urgently needed to guide medical research and improve clinical diagnosis. Here, we report the proximity electrochemiluminescence (ECL) generation enabled by gold microbeads (GMBs) for improving the detection sensitivity and multiplexing capacity of ECL immunoassays (ECLIAs). As demonstrated by microscopy and finite element simulation, GMBs can function as spherical ultramicroelectrodes for triggering ECL reactions in solutions. Employing GMBs as solid carriers in the bead-based ECLIA, the electrochemical oxidation of a coreactant can occur at both the GMB surface and the substrate electrode, allowing the coreactant radicals to diffuse only a short distance of â¼100 nm to react with ECL luminophores that are labeled on the GMB surface. The ECL generation via this proximity low oxidation potential (LOP) route results in a 21.7-fold increase in the turnover frequency of ECL generation compared with the non-conductive microbeads that rely exclusively on the conventional LOP route. Moreover, the proximity ECL generation is not restricted by the diffusion distance of short-lived coreactant radicals, which enables the simultaneous determination of multiple acute myocardial infarction biomarkers using size-encoded GMB-based multiplex ECLIAs. This work brings new insight into the understanding of ECL mechanisms and may advance the practical use of multiplex ECLIAs.
