Analytical electrochemiluminescence

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Electrochemiluminescence reaction pathways in nanofluidic devices

Nanofluidic electrochemical devices confine the volume of chemical reactions to femtoliters. When employed for light generation by electrochemiluminescence (ECL), nanofluidic confinement yields enhanced intensity and robust luminescence. Here, we investigate different ECL pathways, namely coreactant and annihilation ECL in a single nanochannel and compare light emission profiles. By high-resolution imaging of electrode areas, we show that different reaction schemes produce very different emission profiles in the unique confined geometry of a nanochannel. The confrontation of experimental results with finite element simulation gives further insight into the exact reaction ECL pathways. We find that emission strongly depends on depletion, geometric exclusion, and recycling of reactants in the nanofluidic device

Conception d'un laboratoire sur fibre pour l'analyse in vivo

International audienceThis work presents the proof of concept of the detection of optical index changes by surface plasmon resonance (SPR) thanks to optical fiber bundles. This proof of concept is the first essential step for the future design of a lab on fiber tool dedicated to molecular analysis for endoscopic diagnosis. Our approach is based on nanotextured optical fiber bundles comprising several thousands of individual optical fibers. These nanostructures were coated by a thin gold layer in order to exhibit interesting optical properties like SPR. The sensitivity of the bundle to optical index changes and the detection limit were measured in retro-reflection. We performed numerical simulations in order to enhance these performances based on an optimization of the fiber end geometry and the gold coating thickness. We finally obtained a detection limit of 10-4 refractive index unit, which is fully compatible with the detection of biological interactions involving large proteins or bacteria. </p

Selective electrochemiluminescent sensing of saccharides using boronic acid-modified coreactant

We report a strategy for modulating the electrogenerated chemiluminescence (ECL) response by integrating a boronic acid to the chemical structure of coreactants. Excellent selectivity for d-glucose was achieved by tuning the linker length of a bis-boronic acid amine coreactant.</p

Rational Design of Electrochemiluminescent Devices

ConspectusElectrochemiluminescence (ECL) is a light-emitting process which combines the intriguing merits of both electrochemical and chemiluminescent methods. It is an extensively used method especially in clinical analysis and biological research due to its high sensitivity, wide dynamic range, and good reliability. ECL devices are critical for the development and applications of ECL. Much effort has been expended to improve the sensitivity, portability, affordability, and throughput of new ECL devices, which allow ECL to adapt broad usage scenarios.In this Account, we summarize our efforts on the recent development of ECL devices including new electrodes, ECL devices based on a wireless power transfer (WPT) technique, and novel bipolar electrochemistry. As the essential components in the ECL devices, electrodes play an important role in ECL detection. We have significantly improved the sensitivity of luminol ECL detection of H2O2 by using a stainless steel electrode. By using semiconductor materials (e.g., silicon and BiVO4), we have exploited photoinduced ECL to generate intense emission at much lower potentials upon illumination. For convenience, portability, and disposability, ECL devices based on cheap WPT devices have been designed. A small diode has been employed to rectify alternating current into direct current to dramatically enhance ECL intensity, enabling sensitive ECL detection using a smart phone as a detector. Finally, we have developed several ECL devices based on bipolar electrochemistry in view of the convenience of multiplex ECL sensing using a bipolar electrode (BPE). On the basis of the wireless feature of BPE, we have employed movable BPEs (e.g., BPE swimmers and magnetic rotating BPE) for deep exploration of the motional and ECL properties of dynamic BPE systems. To make full use of the ECL solution, we have dispersed numerous micro-/nano-BPEs in solution to produce intense 3D ECL in the entire solution, instead of 2D ECL in conventional ECL devices. In addition, the interference of ECL noise from driving electrodes was minimized by introducing the stainless steel with a passivation layer as the driving electrode. To eliminate the need for the fabrication of electrode arrays and the interference from the driving electrode and to decrease the applied voltage, we develop a new-type BPE device consisting of a single-electrode electrochemical system (SEES) based on a resistance-induced potential difference. The SEES is fabricated easily by attaching a multiperforated plate to a single film electrode. It enables the simultaneous detection of many samples and analytes using only a single film electrode (e.g., screen-printed electrode) instead of electrode arrays. It is of great potential in clinical analysis especially for multiple-biomarker detection, drug screening, and biological studies. Looking forward, we believe that more ECL devices and related ECL materials and detection methods will be developed for a wide range of applications, such as in vitro diagnosis, point-of-care testing, high-throughput analysis, drug screening, biological study, and mechanism investigation.Conversion lumineuse par électrochimiluminescence photoinduit

Macroporous ultramicroelectrodes for improved electroanalytical measurements

Recent work on the preparation of highly organized macroporous electrodes and nanoporous ultramicroelectrodes has been combined and extended to elaborate macroporous ultramicroelectrodes (UMEs) by template synthesis using colloidal crystals and following two different and complementary methods. On the one hand, arched porous UMEs were prepared, and on the other hand, cylindrical porous UMEs were obtained by using cavity UMEs. These macroporous UMEs have an active surface area which is up to 2 orders of magnitude higher compared to that of a classical disk UME as characterized by cyclic voltammetry. To study their analytical performance, the macroporous UMEs have been modified with a redox-active thiol and also a model bioelectrocatalytical system containing a redox mediator, a cofactor, and glucose-dehydrogenase. In both cases the electrochemical signal is amplified by up to 2 orders of magnitude, which increases significantly the analytical performance of such electrodes and therefore opens up new applications for this kind of miniaturized electrochemical system

Selective electrochemiluminescent sensing of saccharides using boronic acid-modified coreactant

We report a strategy for modulating the electrogenerated chemiluminescence (ECL) response by integrating a boronic acid to the chemical structure of coreactants.</p

Développement de réseaux de capteurs pour l'imagerie chimique de micro-environnements

Mes travaux de recherche portent sur le développement de stratégies originales d'imagerie chimique de micro-environnements. Elles sont basées sur l'utilisation de faisceaux cohérents de fibres optiques associés aux méthodes de l'électrochimie. Dans un premier temps, nous avons développé une méthode d'imagerie dynamique des profils de concentration d'une couche de diffusion plane. Dans un second temps, nous avons réalisé un réseau ordonné de nanocapteurs transparents à la surface d'un faisceau de fibres optiques. Ce réseau aux propriétés opto-électrochimiques est notamment adapté à l'imagerie électrochimiluminescente à distance de composées d'intérêt bioanalytique. Une autre voie de recherche est orientée vers la fabrication et l'utilisation en microscopie à champ proche optique de réseaux de nano-ouvertures de dimension sub-longueur d'onde. Ces travaux sont notamment orientés vers le développement de réseaux de biocapteurs pour l'imagerie en milieu biologique.BORDEAUX1-BU Sciences-Talence (335222101) / SudocSudocFranceF

Développement de réseaux multiplexés de biocapteurs électrochimiques

Ce travail de thèse a porté sur le développement de réseaux de micro- et nanocapteurs opto-électrochimiques pour la bioanalyse. Ils répondent à la demande grandissante dans le domaine de la recherche et du diagnostic pour des outils permettant de réaliser de multiples analyses simultanément avec des échantillons de faibles volumes. Ces nouvelles biopuces de haute densité sont fabriquées à partir de faisceaux cohérents de fibres optiques. Une des deux faces est micro- ou nanostructurée par une attaque chimique, puis fonctionnalisée avec une sonde biologique. La première biopuce est un réseau de nanocapteurs fluorescents à ADN où les sondes ont été immobilisées grâce aux propriétés d électropolymérisation du pyrrole. La lecture est réalisée à distance au travers du faisceau d imagerie. En combinant la technique d immobilisation avec des microleviers électrochimiques, plusieurs sondes différentes ont pu être adressées sur le même réseau nanostructuré. La seconde biopuce permet d effectuer des immunodosages multiplexés en utilisant l imagerie électrochimiluminescente résolue à l échelle d une microsphère. Le développement de cette technique permet de combiner les avantages de l électrochimiluminescence avec des immunodosages multiplexés. L élaboration de ces réseaux allie différentes techniques physico-chimiques, notamment électrochimiques, pour obtenir des biopuces avec un fort potentiel, grâce à une densité et un degré de multiplexage importants.This work presents the development of optoelectrochemical micro- and nanosensor arrays for bioanalytical applications. These platforms respond to the growing need in research and diagnostic for tools allowing multiple and simultaneous analysis in small-volume samples. These new high density biochips are made from coherent optical fiber bundles: one face is micro- or nanostructured by chemical etching and then functionnalized with biological probes. The first biochip is a fluorescent DNA nanosensor array where probes have been immobilized by electrodeposition of a polypyrrole thin film. The detection of the hybridization is remotely performed through the imaging fiber. Different probes were succesfully addressed onto the same nanostructured array thanks to electrochemical cantilevers. The second biochip allows multiplexed sandwich immunoassays using electrochimiluminescent imaging resolved at the single bead level. In particular, the development of this new readout mechanism allows extending electrochemiluminescent detection for multiplexed immunoassays. Design and implementations of both platforms take advantages of different physical and chemical techniques, especially electrochemical, to obtain biochips with a great potential through high density and high multiplexing level.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF