V. Badets, J. Pandard, N. Sojic, S. Arbault

ChemElectroChem, 2016, 3, 2288-2296.

The reactivity of platinized electrode surface (Pt‐black) towards the oxidation of hydrogen peroxide is analyzed in the most common physiological buffer, namely phosphate buffer saline, used in the development of biosensors. It is shown here that the oxidation of hydrogen peroxide by Pt‐black involves first the adsorption of phosphate anions, which facilitates the oxidation of hydrogen peroxide at lower potentials when compared to classic polycrystalline platinum. This gives insight in the excellent analytical features of platinized electrodes for the detection of H2O2, even at nanomolar concentrations. The reactivity of platinized electrodes can be further improved by an oxygen plasma treatment. We demonstrate herein that such treatment creates an outermost layer of PtO2 oxides on the deposit, which improves the oxidation of hydrogen peroxide thermodynamically and kinetically, as well as of hydroquinone and superoxide radical anion.

2016 32

 

F. Girard, V. Badets, S. Blanc, K. Gazeli, L. Marlin, L. Authier, P. Svarnas, N. Sojic, F. Clément S. Arbault

RSC Advances, 2016, 6, 78457–78467.

Cold Atmospheric Plasmas (CAPs) or Non Thermal Plasmas (NTPs) are increasingly used for biomedical applications. Herein, we studied the interactions of such CAPs, typically atmospheric ionization waves produced in a helium–nitrogen mixture (He/1% N2) with a commonly used physiological liquid in biology, e.g. Phosphate Buffered Saline solution (PBS) at pH 7.4. Optical Emission Spectroscopy (OES) of the plasma phase revealed the formation in the He/1% N2 CAP of nitric oxide NO and hydroxyl HO˙ derivatives which can lead to numerous Reactive Oxygen and Nitrogen Species (RONS) after dissolution in the exposed PBS. Chemical changes in solution were first assessed by conductimetry and pHmetry; these experiments showed that an evaporation of the solution occurred under gas exposition and was amplified by the CAPs, being mostly related to the interaction between the ionization wave and the gas flow. Further, UV-visible absorption spectroscopy was used to identify and quantify long-lived RONS, namely nitrite (NO2), nitrate (NO3), as well as a short-lived species, i.e. peroxynitrite anion (ONOO). The production in physiological solution of ONOO under CAP exposure is demonstrated for the first time, based on experiments at two pH conditions (7.4 and 12) and on the analysis of decomposition kinetics of this unstable species. The combination of complementary physico-chemical techniques allows to decipher the complex reactivity of CAPs from the plasma phase to the liquid phase.

2016 31

 

V.S.R. Vajrala, E. Suraniti, M. Rigoulet, A. Devin, N. Sojic, S. Arbault

Integrative Biology, 2016, 8, 836-843.

Microwell arrays have been developed to monitor simultaneously, and on a large scale, multiple metabolic responses of single mitochondria. Wells of 50 to 1000 μm-diameter were prepared based on easy structuration of thin polydimethylsiloxane layers (PDMS; 100 μm thickness). Their surface treatment with oxygen plasma allowed the immobilization in situ and observation with time of populations of single isolated mitochondria. Their metabolic activities could be monitored individually by fluorescence microscopy under several activation/inhibition conditions. We measured the concomitant variations of two main metabolic parameters - the endogenous NADH level and the internal membrane potential difference Δψ owing to a cationic fluorescent probe (TMRM) - at energized, uncoupled and inhibited stages of the mitochondrial respiratory chain. Microwell arrays allowed analyses on large populations, and consequently statistical studies with a single organelle resolution. Thus, we observed rapid individual polarizations and depolarizations of mitochondria following their supply with the energetic substrate, while an averaged global polarization (increase of TMRM fluorescence within mitochondria) and NADH increase were detected for the whole population. In addition, statistical correlation studies show that the NADH content of all mitochondria tends toward a metabolic limit and that their polarization-depolarization ability is ubiquitous. These results demonstrate that PDMS microwell platforms provide an innovative approach to better characterize the individual metabolic status of isolated mitochondria, possibly as a function of their cell or organ origin or in different physio-pathological situations.

 

F. Sékli Belaïdi, E. Vanhove, W. Tiddi, M. Polverela, G. Lemercier, A. Lecestre, P. Dubreuil, J. Launay, S. Arbault, P. Temple-Boyer

Sensors Actuators B-Chemical, 2016, 232, 345-356.

In this work, we report the fabrication and the electrochemical characterization of recessed disk microelectrodes (DME) and ring nanoelectrodes (RNE) integrated in microwell arrays. Such configuration has all advantages of microelectrodes arrays but is more suitable for electrochemical measurement in sub-picolitre volumes (∼0.3 pL). The technological process based on the reactive ion etching of a SiO2/Ti/Pt/Ti/SiO2 stack is optimized in order to integrate RNE arrays on transparent glass substrate. Multiphysic simulations and electrochemical characterizations are conducted in order to study and improve the amperometric behaviour of recessed ring nanoelectrodes according to their geometry. A good fit is shown between experimental, theoretical and simulation results, allowing full understanding of the electrochemical detection properties of RNE-based microwell arrays. Then, a “generation − collection mode” chronoamperometric approach is proposed to evaluate experimentally the collection ratio of RNE arrays and compare it with simulation results. Finally, first electrochemical characterizations in sub-picolitre volumes are conducted with anti-oxidant species. All these results demonstrate that recessed ring nanoelectrode arrays are fitted to the detection of bio-electrochemical species at the microscale and, consequently to single mitochondrion or single sub-cellular organelle analysis.

2016 30

 

T. Yutthalekha,C. Wattanakit,V. Lapeyre,S. Nokbin,C. Warakulwit, J. Limtrakul, A. Kuhn 

Nature Commun. 2016, 7: 12678

see also CNRS press release

The synthesis of chiral compounds is of crucial importance in many areas of society and science, including medicine, biology, chemistry, biotechnology and agriculture. Thus, there is a fundamental interest in developing new approaches for the selective production of enantiomers. Here we report the use of mesoporous metal structures with encoded geometric chiral information for inducing asymmetry in the electrochemical synthesis of mandelic acid as a model molecule. The chiral-encoded mesoporous metal, obtained by the electrochemical reduction of platinum salts in the presence of a liquid crystal phase and the chiral template molecule, perfectly retains the chiral information after removal of the template. Starting from a prochiral compound we demonstrate enantiomeric excess of the (R)-enantiomer when using (R)-imprinted electrodes and vice versa for the (S)-imprinted ones. Moreover, changing the amount of chiral cavities in the material allows tuning the enantioselectivity.

2016-19

Deciphering the Platinized Surface Reactivity to Improve the Detection of Hydrogen Peroxide in Bioanalyses
Tuesday, 09 October 2018
V. Badets, J. Pandard, N. Sojic, S. Arbault ChemElectroChem, 2016, 3, 2288-2296. The reactivity of platinized electrode surface (Pt‐black) towards the oxidation of hydrogen peroxide is analyzed in...
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Formation of reactive nitrogen species including peroxynitrite in physiological buffer exposed to cold atmospheric plasma
Tuesday, 09 October 2018
F. Girard, V. Badets, S. Blanc, K. Gazeli, L. Marlin, L. Authier, P. Svarnas, N. Sojic, F. Clément S. Arbault RSC Advances, 2016, 6, 78457–78467. Cold Atmospheric Plasmas (CAPs) or Non Thermal...
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Integration of ring nanoelectrodes into microwells for the bioelectrochemical analysis in sub-picolitre volumes
Tuesday, 09 October 2018
F. Sékli Belaïdi, E. Vanhove, W. Tiddi, M. Polverela, G. Lemercier, A. Lecestre, P. Dubreuil, J. Launay, S. Arbault, P. Temple-Boyer Sensors Actuators B-Chemical, 2016, 232, 345-356. In this work,...
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PDMS microwells for multi-parametric monitoring of single mitochondria in a large scale: a study of the mitochondrial membrane potential and endogenous NADH
Tuesday, 09 October 2018
V.S.R. Vajrala, E. Suraniti, M. Rigoulet, A. Devin, N. Sojic, S. Arbault Integrative Biology, 2016, 8, 836-843. Microwell arrays have been developed to monitor simultaneously, and on a large scale,...
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Combining Microfluidics and FT-IR Spectroscopy: Towards spatially resolved information on chemical processes
Friday, 13 October 2017
A. Perro, G. Lebourdon, S. Henry, S. Lecomte, L. Servant, S. Marre React. Chem. Eng., 2016,1, 577-594. This review outlines the combination of infrared spectroscopy and continuous microfluidic...
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Essential Role of Electrode Materials in Electrochemiluminescence Applications
Thursday, 01 December 2016
Giovanni Valenti, Andrea Fiorani, Haidong Li, Neso Sojic and Francesco Paolucci ChemElectroChem, 2016, 3, 1990-1997 (selected as spotlights in...
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Combined Local Anodization of Titanium and Scanning Photoelectrochemical Mapping of TiO2 Spot Arrays
Tuesday, 01 November 2016
V. Badets, G. Loget, P. Garrigue, N. Sojic,  D. Zigah Electrochimica Acta, 2016, 222, 84–91   Localized growth of TiO2 and rapid screening of TiO2...
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Asymmetric synthesis using chiral encoded metal
Wednesday, 12 October 2016
T. Yutthalekha,C. Wattanakit,V. Lapeyre,S. Nokbin,C. Warakulwit, J. Limtrakul, A. Kuhn  Nature Commun. 2016, 7: 12678 see also CNRS press release The synthesis of chiral compounds is of crucial...
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Nanostructured Antimony-Doped Tin Oxide Layers with Tunable Pore Architectures as Versatile Transparent Current Collectors for Biophotovoltaics
Wednesday, 12 October 2016
K. Peters, H. N. Lokupitiya, D. Sarauli, M. Labs, M. Pribil, J. Rathouský, A. Kuhn, D. Leister, M. Stefik, D. Fattakhova-Rohlfing  Adv. Funct. Mater. 2016, 26, 6682–6692 Nanostructured...
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Selective Electrochemiluminescent Sensing of Saccharides using Boronic Acid-Modified Coreactant
Wednesday, 05 October 2016
H. Li, A. C. Sedgwick,  M. Li, R. A. R. Blackburn, S. D. Bull, S. Arbault, T. D. James and N. Sojic Chem. Comm., 2016, 52, 12845-12848. We report a strategy for modulating the electrogenerated...
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Antagonist Effects Leading to Turn-on Electrochemiluminescence in Thermoresponsive Hydrogel Films
Wednesday, 05 October 2016
H. Li, M. Sentic, V. Ravaine and N. Sojic Phys. Chem. Chem. Phys., 2016, in press We report the effects of the swell-to-collapse transition on the electrochemical and electrochemiluminescent (ECL)...
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Physicochemical and Electronic Properties of Cationic [6]Helicenes, from Chemical and Electrochemical Stabilities to Far-Red (Polarized) Luminescence
Wednesday, 05 October 2016
J. Bosson, G. M. Labrador, S. Pascal, F.-A. Miannay, O. Yushchenko, H. Li, L. Bouffier, N. Sojic, R. C. Tovar, G. Muller, D. Jacquemin, A. D. Laurent, B. Le Guennic, E. Vauthey, J. Lacour Chemistry-A...
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Analytical Electrochemiluminescence
Wednesday, 05 October 2016
H. Cui, F. Paolucci, N. Sojic, G. Xu Analytical and Bioanalytical Chemistry, 2016, 408, 7001–7002
Direct oxidative pathway from amplex red to resorufin revealed by in situ confocal imaging
Tuesday, 04 October 2016
P. Lefrançois, V. S. R. Vajrala, I. B. Arredondo, B. Goudeau, T. Doneux, L. Bouffier, S. Arbault Phys. Chem. Chem. Phys., 2016, 18, 25817-25822. Amplex Red (AR) is a very useful chemical probe that...
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Drainage dynamics of thin-liquid films containing soft PNiPAM microgels : influence of the cross-linking density and concentration
Monday, 25 July 2016
L. Keal, V. Lapeyre, V. Ravaine, V. Schmitt and C. Monteux Soft Matter, 2016, Accepted Manuscript We investigate the drainage dynamics of thin liquid foam films containing PNiPAM microgels...
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Saccharide-induced modulation of photoluminescence lifetime in microgels
Monday, 25 July 2016
S. A. Denisov, F. Pinaud, M. Chambaud, V. Lapeyre, B. Catargi, N. Sojic, N. D. McClenaghan, V. Ravaine Phys. Chem. Chem. Phys., 2016,18, 16812-16821 Sugar-responsive microgels were prepared by the...
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Templated growth of gold satellites on dimpled silica cores
Monday, 18 July 2016
C. Chomette, E. Duguet, S. Mornet, V. N. Manoharan, N. B. Schade, C. Hubert, S. Ravaine, A. Perro and M. Treguer-Delapierre Faraday Discussion, 2016. We synthesize robust clusters of gold...
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Elaboration of Metal Organic Framework Hybrid Materials with Hierarchical Porosity by Electrochemical Deposition-Dissolution
Saturday, 16 July 2016
C. Warakulwit, S. Yadnum, C. Boonyuen, C. Wattanakit, A. Karajic, P. Garrigue, N. Mano, D. Bradshaw, J. Limtrakul, A. Kuhn CrystEngComm, 2016,18, 5095-5100, COVER Rationally designed hierarchical...
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Coupling Electrochemistry with Fluorescence Confocal Microscopy To Investigate Electrochemical Reactivity: A Case Study with the Resazurin-Resorufin Fluorogenic Couple
Sunday, 05 June 2016
T. Doneux, L. Bouffier, B. Goudeau, S. Arbault.  Anal. Chem., 2016, 88, 6292-6300.  The redox couple resazurin-resorufin exhibits electrofluorochromic properties which are investigated...
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Regioselective functionalization of dimpled silica particles
Monday, 30 May 2016
C. Hubert,  C. Chomette,  P.-E. Rouet,  A. Désert,  M. Treguer-Delapierre, J. Majimel,  S. Mornet,  A. Perro,  E. Duguet,  S. Ravaine Coll. Surf. A...
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Dual enzymatic detection by bulk electrogenerated chemiluminescence
Tuesday, 24 May 2016
A. de Poulpiquet, B. Diez-Buitrago, M. Dumont Milutinovic, M. Sentic, S. Arbault, L. Bouffier, A. Kuhn, N. Sojic Anal. Chem., 2016, 88, 6585–6592 The combination of enzymes, as recognition...
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Generation of electrochemiluminescence at bipolar electrodes: concepts and applications
Tuesday, 17 May 2016
L. Bouffier, S. Arbault, A. Kuhn, N. Sojic Anal. Bioanal. Chem., 2016, 408, 7003–7011 Bipolar electrochemistry (BPE) is an unconventional technique where a conducting object is addressed...
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Real-time electrochemical LAMP: a rational comparative study of different DNA intercalating and non-intercalating redox probes
Tuesday, 17 May 2016
A. Martin, L. Bouffier, K. B. Grant, B. Limoges, D. Marchal Analyst, 2016, 141, 4196-4203. We present a comparative study of ten redox-active probes for use in real-time electrochemical loop-mediated...
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Bright Electrogenerated Chemiluminescence of a Bis-donor Quadrupolar Spirofluorene Dye and its Nanoparticles
Wednesday, 11 May 2016
H. Li, J. Daniel, J.-B. Verlhac, M. Blanchard-Desce, N. Sojic Chem. Eur. J., 2016, 22, 12702-12714 A series of symmetric fluorescent dyes built from a spirofluorene core, bearing electroactive...
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Double remote electrochemical addressing and optical readout of electrochemiluminescence at the tip of an optical fiber
Wednesday, 11 May 2016
H. Li, P. Garrigue, L. Bouffier, S. Arbault, A. Kuhn, N. Sojic Analyst, 2016, 141, 4299-4304 In this work, we report an original strategy for the wireless electrochemical generation of light at...
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Microscopic imaging and tuning of electrogenerated chemiluminescence with boron-doped diamond nanoelectrode arrays
Wednesday, 11 May 2016
M. Sentic, F. Virgilio, A. Zanut, D. Manojlovic, S. Arbault, M. Tormen, N. Sojic, P. Ugo Anal. Bioanal. Chem., 2016, 408, 7085–7094 Nanoelectrode arrays (NEAs) are increasingly applied for a...
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Dual-color electrogenerated chemiluminescence from dispersions of conductive micro-beads addressed by bipolar electrochemistry
Wednesday, 11 May 2016
A. de Poulpiquet, B. Diez-Buitrago, M. Milutinovic, B. Goudeau, L. Bouffier, S. Arbault, A. Kuhn, N. Sojic ChemElectroChem, 2016, 3, 404-409 Bipolar electrochemistry (BPE) is exploited here to...
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Patchy colloidal particles for programmed self-assembly
Friday, 08 April 2016
E. Duguet, C. Hubert, C. Chomette, A. Perro, S. Ravaine   C. R. Chimie. 2016, 19, 173  An increasing theoretical and experimental effort has been recently dedicated to the design and the...
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A Compelling Case for Bipolar Electrochemistry
Friday, 11 March 2016
A. Kuhn, R. M. Crooks, S. Inagi ChemElectroChem 2016, 3, 351-352 Bipolar electrochemistry is a wireless way of carrying out redox reactions, which is currently undergoing a renaissance highlighted by...
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Electric fields for generating unconventional motion of small objects
Thursday, 14 January 2016
L. Bouffier, V. Ravaine, N. Sojic and A. Kuhn.  Curr. Opin. Colloid Interface Sci., 2016, 21, 57-64. Electric fields can be used in several ways to generate motion of objects. In this article we...
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Selective Functionalization of Graphene Peripheries by using Bipolar Electrochemistry
Monday, 11 January 2016
L. Zuccaro, A. Kuhn, M. Konuma, H. Ki Yu, K. Kern, K. Balasubramanian ChemElectroChem, 2016, 3, 372-377. We present a contactless strategy based on bipolar electrochemistry for the local chemical...
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Early Diagnosis of fungal Infections using piezomicrogravimetric and electric Chemosensors based on Polymers molecularly imprinted with D-arabitol
Monday, 11 January 2016
M. Dabrowski, P. Sindhu Sharma, Z. Iskierko, K. Noworyta, M. Cieplak, S. Oborska, A. Kuhn, W. KutnerBiosensors and Bioelectronics, 2016, 79, 627-635. An elevated concentration of D-arabitol in urine,...
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