G. S. Kassahun, E. D. Farias, S. Benizri, C. Mortier, A. Gaubert, G. Salinas, P. Garrigue, A. Kuhn, D. Zigah, P. Barthélémy
Inserting complex biomolecules such as oligonucleotides during the synthesis of polymers remains an important challenge in the development of functionalized materials. In order to engineer such a biofunctionalized interface, a single-step method for the covalent immobilization of oligonucleotides (ON) based on novel electropolymerizable lipid thiophene-oligonucleotides (L-ThON) conjugates was employed. Here, we report a new thiophene phosphoramidite building block for the synthesis of modified L-ThON. The biofunctionalized material was obtained by direct electropolymerization of L-ThONs in the presence of 2,2’-Bithiophene (BTh), to obtain a copolymer film on ITO electrodes. In-situ electro-conductance measurements and microstructural studies showed that the L-ThON was incorporated in the BTh copolymer backbone. Furthermore, the covalently immobilized L-ThON sequence showed selectivity in subsequent hybridization processes with a complementary target, demonstrating that L-ThON can directly be used for manufacturing materials via an electropolymerization strategy. These results indicate that L-ThONs are promising candidates for the development of stable ON-based bio-electrochemical platforms.
G. Salinas, G. Bonetti, R. Cirilli, T. Benincori, A. Kuhn, S. Arnaboldi
Bipolar electrochemistry can be employed in the context of chiral recognition in order to obtain useful analytical readouts of enantiomeric analytes. Herein, we employ this concept for the simultaneous determination of two enantiomers present in solution, and its possible use as transduction mechanism for complex real matrices analysis. This approach is based on the combination of the enantioselective electrooxidation of only one of the two antipodes of a chiral analyte with the emission of light from light-emitting diodes (LEDs). A double hybrid device was designed, using the enantiomers of an inherently chiral oligomer and a bare gold wire as the anode and cathode of a green and red LED. By applying an appropriate voltage, the wirelessly induced redox reactions trigger light emission only when the probe with the right configuration is present in solution. This device was used to simultaneously measure the ratio between L- and D-Tryptophan, both present in solution and to quantify L-ascorbic acid in a commercial juice sample. The measurement correlates with the value reported on the sample specifications. These results illustrate the possible use of such light-emitting bipolar devices as analytical tools for qualitative and quantitative measurements of enantiomeric excess, even in real samples.
M. Ketkaew, S. Assavapanumat, S. Klinyod, A. Kuhn, C. Wattanakit
The sustainable conversion of biomass-derived compounds into high added-value products is a very important contemporary scientific challenge. In this context, we report here the simultaneous electro-oxidation/-reduction of a biomass-derived compound in a one-pot approach using bipolar electrochemistry. Bifunctional Pt/Au Janus electrocatalysts are employed for a selective conversion of furfural into both, furfuryl alcohol and furoic acid, which can’t be achieved when using non-Janus particles. The results emphasize the benefits of bipolar electrochemistry in the frame of electrosynthesis processes.
C. Wattanakit and A. Kuhn
The development of chiral electrodes plays an important role in various areas, including chemical science, materials engineering, analytical chemistry, pharmaceutics, cosmetics, and catalysis. Over the past decades, various approaches have been used to design chiral electrodes, such as the adsorption of chiral/achiral molecules on metal electrode surfaces, binding of chiral ligands to metal surfaces, cutting a bulk metal to break the symmetric metal structure, and molecular imprinting. In this chapter, we discuss recent progress related to the development of such chiral metal electrodes by following these different strategies. In addition, their potential applications with respect to enantioselective analysis, asymmetric synthesis, and chiral separation will be discussed. This chapter will also illustrate perspectives for the fabrication and use of chiral metal electrodes in the frame of chiral technologies.
S. M. Beladi-Mousavi, G. Salinas, N. Antonatos, V. Mazanek, P. Garrigue, Z. Sofer, A. Kuhn
Graphene has unique characteristics that are appealing for energy-related applications such as ultra-lightweight and high surface-area/electrical-conductivity. However, generating functional graphene sheets is still a very challenging task. Here, a novel approach based on an original bipolar electrochemistry set-up, using a quasi-2D reaction layer, is suggested, which allows a precise control of dispersibility and conductivity of graphene sheets. In this system, a freestanding 2D layer of aqueous solution, containing 2D graphene oxide (GO) sheets, is placed between two platinum feeder electrodes, which are used to apply an electric field. As a result, the GO sheets experience a sufficiently high polarization to cause their transformation into reduced GO (rGO). The degree of reduction can be readily controlled by the field strength and exposure time, resulting in a wide range of rGO with different conductivity/dispersibility features. The partially reduced GO (prGO) sheets with engineered conductivity/dispersibility are used to prepare aqueous composites with a redox-polymer for organic battery applications. Additonally, at higher potentials, Pt nanoparticles are released from the feeder electrodes and attached to rGO sheets. The sheets were used for catalyzing hydrogen evolution reaction with a performance comparable to bulk Pt.
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