9,10-Phenanthrenequinone as a redox mediator for the imaging of yeast cells by scanning electrochemical microscopy

Yeast cells Saccharomyces cerevisiae were investigated by scanning electrochemical microscopy (SECM) at generation-collection mode. A two redox mediator based system was designed and adapted in order to evaluate redox activity of yeast cells. One redox mediator was 9,10-phenanthrenequinone (PQ), which was lipophilic and was incorporated within the cell membrane. The second redox mediator was K-3[Fe(CN)(6)] (potassium ferricyanide), which is hydrophilic and was acting as an electron shuttle between PQ which was incorporated within cell membrane, and the SECM electrode. The most efficient concentrations of redox mediators suitable for the visualization of the redox process of yeast cells were determined as 0.6 mmol L-1 for potassium ferricyanide and 0.04 mmol L-1 for PQ in the presence of 60 mmol L-1 of glucose. (C) 2015 Elsevier B.V. All rights reserved.