S. Arnaboldi, B. Gupta, T. Benincori, G. Bonetti, R. Cirilli, A. Kuhn

Anal.Chem., 2020, in press, doi.org/10.1021/acs.analchem.0c01817

Chiral discrimination is of crucial importance for many applications, including drug cross checking and electronic tongue type devices. In a typical sensing scheme, an enantiomeric selector is combined with an appropriate transduction mechanism. We propose here a hybrid material composed of an electrically conducting oligomer i.e. oligo-(3, 3’-dibenzothiophene) bearing inherently chiral features, and polypyrrole as a support which can undergo electrochemical actuation. The combination of both leads to a freestanding film that is addressable in a wireless way based on the principle of bipolar electrochemistry. The induced redox reactions lead to well-pronounced actuation when DOPA with the right chirality is present in solution as a model analyte, whereas absolutely no electromechanical response is measured for the wrong enantiomer. This constitutes a straightforward and absolute read out of chiral information where the amplitude of actuation is correlated with the concentration of the analyte. Optimization of the scheme results in highly efficient bending, and thus opens up new directions in the field of chiral technologies.

2020 10

G. Salinas, A. Villarroel Marquez, M. Idir, S. Shinde, B. A. Frontana-Uribe, M. Raoux, J. Lang, E. Cloutet, A. Kuhn

ChemElectroChem, 2020, 7, 2826-2830

An electropolymerized ion selective PEDOT analog is presented in this communication. Poly-(2-phenyl-15crown-5-(3,4-ethylene-dioxythiophene)-amine) (PEDOT-Crown15) showed excellent electrochemical stability with a fast electron transfer (ΔEp = 50 mV). In comparison with unmodified PEDOT, a faster change from isolating to conducting state was observed. This is attributed to the formation of a well-ordered internal polymer matrix, caused by the aniline-Crown15 moiety. In-situ electrochemical conductance measurements in the presence of different monovalent cations showed high affinity for Na+ ions, as evidenced by the decrease of the conductance of the polymer in comparison with K+ and Li+. This selectivity is attributed to a limitation of the charge hopping conductance.

2020 09

 

H. Li, V. Ravaine, N. Sojic

Journal of Analysis and Testing, 4, 2020, 107-113

Electrochemiluminescence (ECL) has attracted considerable interest for many applications such as microscopy, (bio)analysis, light-emitting materials or devices. In this work, we report the fabrication and characterization of ECL-active hydrogel films with tunable thickness. The redox films were prepared by electrochemically-assisted radical polymerization by potential cycling of a PBS solution containing the monomer N-isopropylacrylamide, the initiator potassium persulfate, the cross-linker N,N′-methylenebis(acrylamide) and the Ru(bpy)3 monomer. The deposits were easily prepared in a rapid and well-controlled one-step procedure. The resulting homogeneous films are composed of a poly(N-isopropylacrylamide) (pNIPAM) matrix, which incorporates covalently [Ru(bpy)3]2+ centers. The thickness and the number of ECL-active sites is tuned by controlling the number of voltammetric scans. The deposited pNIPAM films are permeable to water-soluble chemicals such as the coreactant tri-n-propylamine (TPrA). The voltammetric characterization shows a continuous increase of the number of redox active sites. Results indicate that ECL signals are proportional to the number of electrodeposited [Ru(bpy)3]2+ centers. Such approach combining ECL and stimuli-responsive hydrogels open exciting prospects for developing new (bio)sensing materials.

S. Voci, J.-B. Verlhac, F. Polo, G. Clermont, J. Daniel, F. Castet, M. Blanchard-Desce, N. Sojic

Chem. Eur. J., 2020, DOi: 10.1002/chem.202000474

We synthesized and characterized a series of dyes built from spirofluorene or truxene core. The quadrupolar spirofluorene system is the initial building unit for the design and preparation of more complex star-shaped dyes consisting of a truxene core bearing three di- or triphenylamine moieties with or without thiophene connector. Their photophysical, electrochemical, and electrochemiluminescence (ECL) properties were first investigated in solution. Structure/activity relationships were derived and rationalized by comparing the quadrupolar system and trigonal truxene-core derivatives using computational studies. The photophysical and redox characteristics are drastically tuned by the introduction of thiophene bridge and electron-donor substituents at their terminal branches. These comparative studies show the essential role of the stability of both radical cations and anions to obtain efficient ECL dyes. The stabilization of the radicals is directly related to the charge delocalization due to the π-conjugation by the thiophene bridge. The brightest ECL is achieved by annihilation and coreactant (benzoyl peroxide) pathways with the blue-emitting truxene dye, which is 2-time and 4.5-time greater than that of the quadrupolar compound and reference [Ru(bpy)3]2+ emitter, respectively. Such an extensive study on these extended π-conjugated molecules presenting different core structures may guide the design and synthesis of new ECL dyes with a strong efficiency.

TOC CEJ2020

P. Dutta, D. Han, B. Goudeau, D. Jiang, D. Fang, N. Sojic

Biosensors and Bioelectronics, 2020, DOI: 10.1016/j.bios.2020.112372

Electrochemiluminescence (ECL) is a powerful (bio)analytical method based on an optical readout. It is successfully applied in the heterogeneous format for immunoassays and imaging using the model and most widely used ECL system, which consists of the immobilized [Ru(bpy)3]2+ label with tripropylamine (TPA) as a coreactant. However, a major drawback is the significant decrease of the ECL intensity over time. Herein, to decipher the process responsible for this progressive loss of ECL signal, we investigated its electrochemical and photophysical properties by mapping the luminescence reactivity at the level of single micrometric beads. Polystyrene beads were functionalized by the [Ru(bpy)3]2+ dye via a sandwich immunoassay or a peptide bond. ECL emission was generated in presence of the very efficient TPA coreactant. Imaging both photoluminescence and ECL reactivities of different regions (located near or far from the electrode surface) of a [Ru(bpy)3]2+-decorated bead allows us to demonstrate the remarkable photophysical stability of the ECL label, even in presence of the very reactive electrogenerated TPA radicals. We show that the ECL vanishing correlates directly with the lower TPA oxidation current. Finally, we propose a simple electrochemical treatment, which allows to regenerate the electrode surface and thus to recover several times the strong initial ECL signal. The reactivity imaging approach provides insights into the ECL mechanism and the main factors governing the stability of the emission, which should find promising ECL applications in bioassays and microscopy.

TOC BIOS2020

Thumbnail Dezest M., Bulteau A.L., Quinton D., Chavatte L., Le Béchec M., Arbault S., Salvayre A.N., Cousty S., Clément F. PLOS One, 2017, 12(3) Cold atmospheric pressure plasmas (CAPPs) are known to have...
Thumbnail C. Wattanakit, T. Yutthalekha, S. Asssavapanumat, V. Lapeyre, A. Kuhn Nature Comm. 2017, 8, 2087 see also CNRS press release Asymmetric synthesis of molecules is of crucial importance to obtain...
Thumbnail Giovanni Valenti, Sabina Scarabino, Bertrand Goudeau, Andreas Lesch, Milica Jovic, Elena Villani, Milica Sentic, Stefania Rapino, Stephane Arbault, Francesco Paolucci, and Neso Sojic J. Am. Chem....
Thumbnail V. Eßmann, S. Voci, G. Loget, N. Sojic, W. Schuhmann, A. Kuhn J. Phys. Chem. Lett. 2017,8, 4930–4934   Bipolar electrochemistry has been shown to enable and control various kinds of propulsion of...
Thumbnail Guangnan Meng, Vinothan N. Manoharan and Adeline Perro Soft Matter, 2017,13, 6293-6296 We design polystyrene–poly(N′-isopropylacrylamide-co-acrylic acid) core–shell particles that exhibit...
Thumbnail J. Gao, S. Chen, F. AlTal, S. Hu, L. Bouffier, G. Wantz.  ACS Appl. Mater. Interfaces, 2017, 9, 32405–32410.  A linear array of aluminum discs is deposited between the driving electrodes of an...
Thumbnail B. Gupta, B. Goudeau, A. Kuhn Angew.Chem. Int. Ed. 2017, 56, 14183-14186 see also Highlight in Chemistry Views and CNRS press release Electrochemical actuation of conducting polymers usually...
Thumbnail Z. Ali Fattah, L. Bouffier, A. Kuhn Applied Materials Today 2017, 9, 259–265, COVER Self-propelled micro/nanoswimmers performing directional motion are of great potential nowadays in the frame of...
Thumbnail T.D. Le, D. Lasseux, X.P. Nguyen, G. Vignoles, N. Mano, A. Kuhn Chemical Engineering Science 2017, 173, 153–167 A multi-scale model of diffusion/reaction at play in a porous electrode is developed...
Thumbnail M. Dabrowski, M. Cieplak, K. Noworyta, M. Heim, W. Adamkiewicz, A. Kuhn, P. S. Sharma, W. Kutner J. Mater. Chem. B, 2017,5, 6292-6299 Molecular imprinting in polymers leads, among others, to...
Thumbnail L. Bouffier, T. Doneux.  Current Opinion in Electrochemistry, DOI: 10.1016/j.coelec.2017.06.015. Electrochemistry and fluorescence microscopy are two complementary transduction techniques that offer synergetic...
Thumbnail G. Di Martino,V. A. Turek,  A. Lombardi, I.  Szabó, B. de Nijs,  A. Kuhn, E. Rosta, J.J. Baumberg Nano Lett. 2017, 17, 4840-4845 We study in real time the optical response of individual plasmonic...
Thumbnail Rémy Bois, Sabina Scarabino, Valérie Ravaine, Neso Sojic Langmuir, 2017, DOI: 10.1021/acs.langmuir.7b01585 We describe a method to confine electrochemiluminescence (ECL) at the oil-water interface of emulsion...
Thumbnail D. Zigah, O. Fontaine World Scientific, 2017, ISBN: 978-1-78634-353-6   Bioelectrochemical Systems (BESs) are innovative and sustainable devices. They combine biological and electrochemical...
Thumbnail C. Bodin,  E. Mourad,  D. Zigah,  S. Le Vot,  S. A Freunberger,  F. Favier, O. Fontaine Faraday Discuss., 2017,DOI: 10.1039/C7FD00174F   Nowadays, commercial supercapacitors are based on purely...
Thumbnail S. Tiewcharoen, C. Warakulwit, V. Lapeyre, P. Garrigue, L. Fourier, C. Elissalde, S. Buffière, P. Legros, M. Gayot, J. Limtrakul, A. Kuhn Angew.Chem.Int.Ed. (2017) 56, 11431-11435, COVER, HOT...
Thumbnail G. Di Martino, V. A. Turek,  C. Tserkezis, A. Lombardi, A. Kuhn, J.J. Baumberg Faraday Discuss., 2017, in press,doi 10.1039/C7FD00130D We study the optical response of individual nm-wide plasmonic...
Thumbnail A. G. Mark, E. Suraniti, J. Roche, H. Richter, A. Kuhn, N. Mano, P. Fischer Lab Chip, 2017, 17, 1761 HOT PAPER see also CNRS press release A variety of diagnostic and therapeutic medical...
Thumbnail I. Malytska, C. Mézière, M. Keilar, L. Hirsch, G. Wantz, N. Avarvari, A. Kuhn, L. Bouffier. Journal of Physical Chemistry C 2017, 121, 12921-12927.   Bipolar electrochemistry has recently emerged as a very...
Thumbnail L. Bouffier, S. Reculusa, V. Ravaine, A. Kuhn. ChemPhysChem 2017, 18, 2637-2642.   A new simple and versatile method for the preparation of surface wetting gradients is proposed. It is based on the...
Thumbnail C.A. Busatto, H. Labie, V. Lapeyre, R. Auzely-Velty, A. Perro, N. Casis, J. Luna, D.A. Estenoz, V. Ravaine Journal of Colloid and Interface Science, 493, 2017, 356–364. Polymer microgels have received...
Thumbnail L. Bouffier, N. Sojic, A. Kuhn Electrophoresis, 2017, 38, 2687-2694. A bipolar electrode is quite unconventional as it behaves simultaneously as an anode and a cathode in contrast to a classic...
Thumbnail M. Dabrowski, M. Cieplaka, P. Sindhu Sharma, P. Borowicz, K. Noworyta, W. Lisowski, F. D'Souza, A. Kuhn, W. Kutner Biosens.&Bioelectron.2017, 94, 155-161 Nanostructured artificial receptor...
Thumbnail Nenad R. Filipovic, Hana Elshaflu, Sonja Grubic, Ljiljana S. Jovanovic, Marko Rodic, Irena Novakovic, Aleksandar Malecevic, Ivana S. Djordjevic, Haidong Li, Neso Sojic, Aleksandar Marinkovic,...
Thumbnail Haidong Li, Silvia Voci, Antoine Wallabregue, Catherine Adam, Geraldine M. Labrador, Romain Duwald, Irene Hernández Delgado, Simon Pascal, Johann Bosson, Jérôme Lacour, Laurent BouffierNeso...