1 Bioelectrochemistry: From Biofuel Cells to Membrane Electrochemistry Valentin Mirčeski Institute of Chemistry Faculty of Natural Sciences and Mathematics “Ss. Cyril and Methodius” University, Skopje Republic of Macedonia

2 Electricity production using living microorganisms Studying the interrelation between the chemical and electrical phenomena in living organisms Major Goals:

3 Galvanic Cell A Galvanic cell converts chemical energy into electricity.

4 Bacterial Fuel Cells A microbial fuel cell converts chemical energy, available in a bio-convertible substrate, directly into electricity.

5 Finneran, K.T., Johnsen, C.V. & Lovley, D.R. Int. J. Syst. Evol. Microbiol. 53, 669–673 (2003). Disadvantages   Power outputs - miliwats.   Yet no commercially applications 80% electron efficiency Advantages   Electricity generation out of wastewater   Glucose-poweredpacemakers   Bio-sensors, and nutrient removal systems

6 paraffin-impregnated graphite electrode T-cells Lymphocytes Immobilized on a Graphite Electrode reference electrodecounter electrode Fluorescent image of cells attached to the electrode. Cyclic Voltammetry

7 reference electrode Electron Transport Catalyzed by a Redox Mediator paraffin-impregnated graphite electrode adsorbed redox mediator counter electrode Redox Mediator 2-palmytoilhydroquinone

8 Catalytic Electron Transfer Mechanisms from T-cells ELECTRODE H2QH2QH2QH2Q Q T-cells (reduced form) 2e - H 2 Q/Q - a redox catalyst T-cells (oxidized form) E vs Ag/AgCl (3 M KCl) / V I /  H2QH2Q H 2 Q + T-cells V. Mirceski et al. in press: Clinical Chemistry and Laboratory Medicine

9 Electrochemistry at a Single Cell Ultramicroelectrodes Image of a disk ultramicroelectrode by electronic microscopy Typical dimensions within the interval: to m

10 Cartoon of a neuronal chemical synapse Exocytose of Neurotransmitters Exocytose

11 Amperometric Detection of Exocytotic Events Series of single vesicular exocytotic events observed through amperometric oxidation of adrenaline molecules From: C Amatore et al. ChemPhysChem 2003, 4,

12 Scanning Electrochemical Microscopy

13 Patch Clamp Ion Transfer through Cellular Membranes

14 Protein-Film Voltammetry

15 Protein-Film and Cyclic Voltammetry

16   The electrode takes the place of one of the enzyme's physiological redox partners.   Controlling the electrode potential one controls the rate of the electron exchange   Controlling the rate of change of the electrode potential, one precisely controls the enzyme's access to substrate Catalysis with Redox Active Enzymes

17 Coupling of the Redox Chemistry with Ion Transfer at Cellular Membranes K + channel complex that catalyzes a redox reaction. K+K+ S. H. Heinemann et al. Science STCE, 2006, 350, 33. K+K+

18 Voltammetry of Artificial Membranes Coupled Electron-Ion Transfer Reaction Edge Plane Pyrolytic Graphite Electrode RedOx + X-X-X-X- Organic film Aqueous electrolyte Cat + X - Reference electrode - e - X-X-X-X- Organic electrolyte TBA + X - Counter Electrode Red (o) + X - (aq) ⇄ Ox + (o) + X - (o) + e -

19 SO 4 2- CH 3 COO - Br - NO 3 - SCN - ClO E vs SCE / V I /  A Role of the Transferring Ions on the Redox Chemistry of the Membrane SW voltammograms for the oxidation of a lutetium complex in the nitrobenzene membrane

20 RedOx + X-X- -e X-X- Edge Pyrolytic Graphite Electrode Cholesterol Membrane at the Liquid|Liquid Interface

E vs. SCE / V I /  A 1 40 ClO 4 - Monitoring of the Cholesterol Membrane Formation with Cyclic Voltammetry

22 E / V I /  A with cholesterol no cholesterol NO 3 - Cholesterol Facilitates the Transfer kinetics of ClO 4 -, NO 3 - and SCN -

23 Q10 electrochemistry

24 Q10 chemical transformation in a basic medium

25 Caclium complexation with Q10-hydroxylated derivatives

26 Caclium complexation with Q10-hydroxylated derivatives