Mediated electron transfer from microbial systems to electrodes represents a promising alternative to Clark electrodes. Electron mediators perform a special function in whole cell biosensors; their role is to replace the electron transfer performed by oxygen, thus preventing the process from the problem of having a low oxygen concentration [1]. Since the first applications of osmium redox polymers for enzyme based reagentless mediated biosensing were described, polymeric mediators still attract attention due to the efficient electron shuttling properties combined with the polymeric structure promoting a stable adsorption as well as a possibility for multiple layers of both immobilised enzymes [2] and microbial cells [3] on the electrode surface.
In the present study applications of flexible Os^2+/3+ functionalised polymers such as poly(1-vinylimidazole)₁₂-[Os(4,4'-dimethyl-2,2'-dipyridyl)₂Cl₂]^2+/3+ and poly(vinyl- pyridine)[Os(N,N'-dimethyl-2,2'-biimidazole)₃]^2+/3+ for efficient electrical wiring of bacterial cells is described. The methylated biimidazole complex was recently reported as a fast redox mediator due to its long tethering to the polymer backbone through a 13-atom-long flexible spacer [4] and also shown to more efficient than other Os-polymers having redox potential values 250-300 mV more positive. Gluconobacter oxydans and Pseudomonas putida DSM 50026 were used as the biological components serving both as model bacteria but also for possible future applications in biosensing and biofuel cells.

[1] P. Skladal, N. O. Morozova, A. N. Reshetilov, Biosens. Bioelectron., 17 (2002) 867.
[2] A. Heller, J. Phys. Chem., 96 (1992) 3579.
[3] I. Vostiar, E. E. Ferapontova, L. Gorton, Electrochem. Commun., 6 (2004) 621.
[4] F. Mao, N. Mano and A. Heller, J. Am. Chem. Soc., 125 (2003) 4951.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/4412 must be provided.

1. Effect of deglycosylation of cellobiose dehydrogenase applied to 3rd generation biosensors and biofuel cells
2. Deglycosylation of glucose oxidase by PNGase F
3. Influence of metal cations on the turnover rate of cellobiose dehydrogenase
4. Electron transfer studies with different sugar oxidizing enzymes and osmium polymers to improve the current density
5. Gold nanoparticle-modified enzyme-based sugar and oxygen sensitive electrodes for biosensing and biofuel cell applications
6. Electrochemical communication between viable bacterial cells and flexible redox polymers
7. Direct electrochemistry of cellobiose dehydrogenase for applications in the third-generation biosensor and biofuel cell
8. Electrochemical Communication between Viable Bacterial Cells and Flexible Redox Polymers
9. Biosensing Applications Of Engineered Pyranose 2-oxidases Wired With Osmium Polymers
10. Anode and cathode reactions for biofuel cells based on direct electron transfer reactions between biological components and electrodes
11. Increasing Biosensor Sensitivity by Length Fractionated Single Walled Carbon Nanotubes
12. Electrical Wiring of Living Bacillus subtilis Cells Using Flexible Osmium-Redox Polymers
13. Some electrochemical properties of laccase immobilised on the Au, IrO_x, or C₆₀-Pd polymer electrode supports
14. Oxygen electroreduction by fungal laccases - combination of electrochemical and spectral data
15. The electrochemistry of a his-tagged microperoxidase assembled onto gold electrodes
16. Electron Transfer in Complex Two-cofactor-containing Enzymes at Alkanethiol-modified Gold Electrodes