Suchergebnisse

The reversible oxidation and reduction of Cytochrome c (Cyt c) is demonstrated with a closed bipolar electrochemical cell (CBPEC). Herein, a 4-electrode configuration was studied with the opposite poles of the bipolar electrode resting in separate aqueous and organic electrolyte solutions, respectively. Using biocompatible indium tin oxide (ITO) slides as the bipolar electrode poles, we investigated the influence of the redox potential of the reductant (decamethyferrocene or dimethylferrocene) in a trifluorotoluene organic phase on the observed voltammetry. Reversible electron transfer was only observed between Cyt c and decamethylferrocene. Use of the weaker dimethylferrocene as the reductant required a larger external bias of the driving electrodes to initiate the electron transfer reaction between the two poles of the bipolar electrode. Consequently, the surface of the ITO slide at the aqueous pole experienced a significant negative cathodic potential and underwent irreversible reduction. The biphasic setup using the 4-electrode CBPEC provides insights into electron transfer processes at an interface between two immiscible electrolyte solutions (ITIES), highlighting the strong probability of observing interfacial electron transfer between decamethylferrocene (but not dimethylferrocene) and Cyt c within the short ~ 1 V polarisable potential window available at an ITIES. ; A. G.-Q. acknowledges funding received from an Irish Research Council Government of Ireland Postdoctoral Fellowship Award (grant number GOIPD/2018/252). G. H. is grateful to the French Programme Investissement d'Avenir (PIA) "Lorraine Université d'Excellence" (Reference No. ANR-15-IDEX-04-LUE). for the partial financial support of this work. The authors are grateful to the support of the Irish Research Council and Campus France for travel support between the French and Irish groups through their joint ULYSSES programme.

Programmed cell death via apoptosis is a natural defence against excessive cell division, crucial for foetal development to maintenance of homeostasis and elimination of precancerous and senescent cells. Here we demonstrate an electrified liquid bio-interface that replicates the molecular machinery of the inner mitochondrial membrane at the onset of apoptosis. By mimicking in vivo cytochrome c (Cyt c) interactions with cell membranes, our platform allows us to modulate the conformational plasticity of the protein by simply varying the electrochemical environment at an aqueous|organic interface. Remarkably, we observe interfacial electron transfer between an organic electron donor decamethylferrocene and O2, electrocatalysed by Cyt c. This interfacial reaction requires partial Cyt c unfolding, mimicking Cyt c in vivo peroxidase activity. As proof-of-concept, we use our electrified liquid bio-interface to identify drug molecules, such as bifonazole, that can potentially downregulate Cyt c and protect against uncontrolled neuronal cell death in neurodegenerative disorders. ; D.T. thanks Science Foundation Ireland (SFI) for computing resources at the SFI/Higher Education Authority Irish Center for High-End Computing (ICHEC). A.G.-Q. acknowledges funding received from an Irish Research Council (IRC) Government of Ireland Postdoctoral Fellowship Award (Grant Number GOIPD/2018/252). G.H. and M.D. are grateful to the French Programme Investissement d'Avenir (PIA) "Lorraine Université d'Excellence" (Reference no. ANR-15-IDEX-04-LUE). M.D.S. and G.H. are grateful to the support of the IRC and Campus France for travel support between the French and Irish groups through their joint ULYSSES programme. DT thanks Science Foundation Ireland (SFI) for support (awards Grant Numbers 15/CDA/3491 and 12/RC/2275_P2).