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Linking Glucose Oxidation to Luminol-based Electrochemiluminescence using bipolar Electrochemistry
Asymmetric Modification of TiO2 Nanofibers with Gold by Electric-Field-Assisted Photochemistry
Stimuli-responsive microgels for electrochemiluminescence amplification
Electropolymerization of Polypyrrole by Bipolar Electrochemistry in an Ionic Liquid
In our last paper published in Langmuir, pyrrole has been electropolymerized on a bipolar electrode - either in ionic liquid or in acetonitrile - and the resulting polymer films were characterized by Scanning Electron Microscopy and by contact profilometry.
A new tool for Transfer of Technology
Launched in last January, the BrivaTech cluster is your privileged interlocutor if you are interested in using some of the technologies developed in the NSysA research group.
Site-Selective Synthesis of Janus-type Metal-Organic Framework Composites
Bipolar electrochemistry is applied in a straightforward way to the site-selective in situ synthesis of metal–organic framework structures. The novelty of the presented work is that the deposit can be intentionally confined to a defined area of a substrate without using masks or templates.
Electrochemistry of Biosystems
Part of our research activities are devoted to the development of sensors and methodologies for the detection of biological activities in order to elucidate with biologists and clinicians fundamental metabolic or genetic mechanisms.
Mapping the Electrogenerated Chemiluminescence Reactivity in Space: Mechanistic Insight into Model Systems Used in Immunoassays
The remarkable characteristics of electrogenerated chemiluminescence (ECL) as a readout method are successfully exploited in microbead-based immunoassays.
Straight-forward Synthesis of Ringed Particles
Here, we report the straightforward chemical synthesis of complex metallic ring structures on the surface of spherical particles using an original template-free bulk process.
Impact of pNIPAM Microgel Size on their Ability to stabilize Pickering Emulsions
In this Langmuir publication, we studied the influence of the particle size on the ability of poly(N-isoprolylacrylamide) microgels to stabilize direct oil-in-water Pickering emulsions. The microgel size wass varied from 250 to 760 nm, the cross-linking density being kept constant.
L. Bouffier, N. Sojic, A. Kuhn
Electrophoresis, 2017, in press
A bipolar electrode is quite unconventional as it behaves simultaneously as an anode and a cathode in contrast to a classic electrochemical setup where the electron-transfer reactions are promoted on two different electrodes. The driving force is the polarization potential established between the solution and the bipolar electrode which allows a wireless electrochemical addressing. In the past decade or so, bipolar electrochemistry (BPE) has encountered a remarkable renewal of interest with extraordinary potentialities ranging from materials science to analytical chemistry. For practical reasons, BPE experiments are very often performed in home-made electrochemical cells comprising tubes or capillaries. This review is focussed on specific applications based on such types of experimental set-ups, from the macroscale where the tube acts only as an ordinary container down to the microscale where specific properties of the capillary come also into play.
M. Dabrowski, M. Cieplaka, P. Sindhu Sharma, P. Borowicz, K. Noworyta, W. Lisowski, F. D'Souza, A. Kuhn, W. Kutner
Nanostructured artificial receptor materials with unprecedented hierarchical structure for determination of human serum albumin (HSA) are designed and fabricated. For that purpose a new hierarchical template is prepared. This template allowed for simultaneous structural control of the deposited molecularly imprinted polymer (MIP) film on three length scales. A colloidal crystal templating with optimized electrochemical polymerization of 2,3′-bithiophene enables deposition of an MIP film in the form of an inverse opal. Thickness of the deposited polymer film is precisely controlled with the number of current oscillations during potentiostatic deposition of the imprinted poly(2,3′-bithiophene) film. Prior immobilization of HSA on the colloidal crystal allows formation of molecularly imprinted cavities exclusively on the internal surface of the pores. Furthermore, all binding sites are located on the surface of the imprinted cavities at locations corresponding to positions of functional groups present on the surface of HSA molecules due to prior derivatization of HSA molecules with appropriate functional monomers. This synergistic strategy results in a material with superior recognition performance. Integration of the MIP film as a recognition unit with a sensitive extended-gate field-effect transistor (EG-FET) transducer leads to highly selective HSA determination in the femtomolar concentration range.
The electrochemistry and annihilation electrochemiluminescence (ECL) of a series of chiral cationic helicene luminophores containing various substituents were investigated in acetonitrile as solvent. The electrochemical characterization evidenced a systematic reversible reduction of the cation whereas the oxidation could be reversible or not depending on the nature of the core heteroatoms within the structure as well as the functional group appendages. One of the key-parameters governing the ECL intensity is indeed the formal redox potentials for the electrogeneration of the neutral radical and dication radical species which will undergo the annihilation reaction. On that basis, a thermodynamic wall of efficiency was proposed in the case of ECL annihilation pathway to predict the formation efficiency of the emitting excited state and eventually light emission strength. This very simple wall is constructed by plotting the difference of formal potentials in function of the fluorescence wavelength delimiting thus two domains where ECL is thermodynamically possible or unfavorable.
Here, we describe a new aspect of multicolor potential-resolved electrochemiluminescence (ECL) based on bipolar electrochemistry (BPE). BPE involves a potential gradient established along a polarized conducting object which thus acts as a bipolar electrode (BE). The resulting driving forces can induce electron-transfer reactions, necessary for processes such as ECL occurring at different longitudinal locations along the same BE. In this work, we exploit the entire spatial domain where anodic polarization occurs to demonstrate for the first time how the potential gradient along a BE may be used to simultaneously resolve the emissions of ECL-active luminophores with differing oxidation potentials. The control of both size and position of the ECL-emitting domains was achieved by tuning the applied electric field. Multicolor light-emission was analyzed in detail to demonstrate spatial and spectral resolution of a solution containing different emitters.
Nenad R. Filipović, Hana Elshaflu, Sonja Grubišić, Ljiljana S. Jovanović, Marko Rodić, Irena Novaković, Aleksandar Malešević, Ivana S. Djordjević, Haidong Li, Nešo Šojić, Aleksandar Marinković, Tamara R. Todorović
First Co(III) complexes with (1,3-selenazol-2-yl)hydrazones as an unexplored class of ligands were prepared and characterized by NMR spectroscopy and X-ray diffraction analysis. Novel ligands act as NNN tridentate chelators forming octahedral Co(III) complexes. The impact of structural changes on ligands' periphery as well as isosteric replacement of sulphur with selenium on electrochemical, and electronic absorption features of complexes are explored. To support the experimental data, density functional theory (DFT) calculations were also conducted. Theoretical NMR chemical shifts, the relative energies and natural bond orbital (NBO) analysis are calculated within the DFT approach, while the singlet excited state energies and HOMO-LUMO energy gap were calculated with time-dependent density functional theory (TD-DFT). The electrophilic f– and nucleophilic f+ Fukui functions are well adapted to ﬁnd the electrophile and nucleophile centres in the molecules. Both, (1,3-selenazol-2-yl)- and (1,3-thiazol-2-yl)hydrazone Co(III) complexes showed potent antimicrobial and antioxidant activity. Significant difference among them was a smaller cytotoxicity of selenium compounds.