M. Feng, A. L. Dauphin, L. Bouffier, F. Zhang, Z. Wang, N. Sojic
Electrochemiluminescence (ECL) behavior of luminol derivative was investigated in reduction on different electrode materials. We found that luminol and its widely used L-012 derivative, emitting at physiological pH values, exhibit strong cathodic ECL emission on iron and stainless steel electrodes with hydrogen peroxide, whereas no ECL signal was observed with other classic electrode materials (Au, Pt, and C). On a Ni electrode, a low cathodic ECL signal was observed. This points out to the essential role of iron-containing materials to enhance the cathodic ECL emission. Under the reported conditions, the cathodic ECL signal of L-012 is comparable to the classically used anodic ECL emission. Thus, dual bright ECL emissions with L-012 were obtained simultaneously in oxidation and in reduction on iron materials as imaged in a wireless bipolar electrochemistry configuration. Such an ECL system generating light emission concomitantly in oxidation and in reduction is extremely rare and it opens appealing (bio)analytical and imaging applications, in biosensing, remote detection, bipolar ECL analysis, and ECL-based cell microscopy.
Y. Zhao, J. Yu, J.-F. Bergamini, Y. Léger, N. Sojic, G. Loget
The photoelectrochemical charge-transfer process occurring at semiconductor surfaces has important implications in the fields of solar fuels and biodetection. Usually, physical light sources located outside the liquid phase, such as a solar simulator, a light-emitting diode (LED), or a laser, are used for photoelectrochemical studies. Here, we report inducing photoelectrochemistry using an electrochemical source of light, that is, the electrochemiluminescence (ECL) emitted by a model co-reactant system. Results reveal that the ECL illumination can activate several semiconductor (SC) photoelectrodes based on n-type Si, n-type GaAs, and p-type Si. We demonstrate that this emitter-receiver concept, based on dual-light conversion, enables photoelectrochemical charge transfer at the solid/liquid interface, which correlates with the ECL intensity. The singularities of this concept lie in the fact that light emission and collection both occur in the liquid phase, that ECL is an easily miniaturizable photon source, and that the SC/liquid junction can be easily implemented. This approach may open perspectives for remote ECL detection strategies and original photoelectrochemical analytical systems.
G. Salinas, S.M. Beladi-Mousavi, A. Kuhn
Recent progress in the field of enzyme-powered micro/nanoswimmers is summarized and discussed, covering different theoretical and mechanistic aspects, as well as potential applications. This is motivated by the increasing number of reports focusing on the design of biocompatible systems, able to move in complex environments and their potential use for biomedical applications. Motion is achieved by enzymatic reactions, enabling bubble-propulsion and self-diffusiophoretic or self-electrophoretic displacement. Single- and multiple-enzyme-powered micro/nanoswimmers are presented as interesting and original systems for cargo delivery, the detection of various analytes and the biodegradation of complex organic molecules.
Y. Liu, H. Zhang, B. Li, J. Liu, D. Jiang, B. Liu, N. Sojic
Herein, a single biomolecule is imaged by electrochemiluminescence (ECL) using Ru(bpy)32+-doped silica/Au nanoparticles (RuDSNs/AuNPs) as the ECL nanoemitters. The ECL emission is confined to the local surface of RuDSNs leading to a significant enhancement in the intensity. To prove the concept, a single protein molecule at the electrode is initially visualized using the as-prepared RuDSN/AuNPs nanoemitters. Furthermore, the nanoemitter-labeled antibody is linked at the cellular membrane to image a single membrane protein at one cell, without the interference of current and optical background. The success in single-biomolecule ECL imaging solves the long-lasting task in the ultrasensitive ECL analysis, which should be able to provide more elegant information about the protein in cellular biology.
C. Zhang, H. Zhang, J. Pi, L. Zhang, A. Kuhn
Electrochemical regeneration of reduced nicotinamide adenine dinucleotide (NADH) is an extremely important challenge for the electroenzymatic synthesis of many valuable chemicals. Although some important progress has been made with modified electrodes concerning the reduction of NAD+, the scale-up is difficult due to mass transport limitations inherent to large-size electrodes. Here, we propose instead to employ a dispersion of electrocatalytically active modified microparticles in the bulk of a bipolar electrochemical cell. In this way, redox reactions occur simultaneously on all of these individual microelectrodes without the need of a direct electrical connection. The concept is validated by using [Rh(Cp*)(bpy)Cl]+ functionalized surfaces, either of carbon felt as a reference material, or carbon microbeads acting as bipolar objects. In the latter case, enzymatically active 1,4-NADH is electroregenerated at the negatively polarized face of the particles. The efficiency of the system can be fine-tuned by controlling the electric field in the reaction compartment and the number of dispersed microelectrodes. This wireless bioelectrocatalytic approach opens up very interesting perspectives for electroenzymatic synthesis in the bulk phase.
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