title: Synthesis of polypyrrole within the cell wall of yeast by redox-cycling of [Fe(CN)6](3-)/[Fe(CN)6](4-).
abstract: Yeast cells are often used as a model system in various experiments. Moreover, due to their high metabolic activity, yeast cells have a potential to be applied as elements in the design of biofuel cells and biosensors. However a wider application of yeast cells in electrochemical systems is limited due to high electric resistance of their cell wall. In order to reduce this problem we have polymerized conducting polymer polypyrrole (Ppy) directly in the cell wall and/or within periplasmic membrane. In this research the formation of Ppy was induced by [Fe(CN)6](3-)ions, which were generated from K4[Fe(CN)6], which was initially added to polymerization solution. The redox process was catalyzed by oxido-reductases, which are present in the plasma membrane of yeast cells. The formation of Ppy was confirmed by spectrophotometry and atomic force microscopy. It was confirmed that the conducting polymer polypyrrole was formed within periplasmic space and/or within the cell wall of yeast cells, which were incubated in solution containing pyrrole, glucose and [Fe(CN)6](4-). After 24h drying at room temperature we have observed that Ppy-modified yeast cell walls retained their initial spherical form. In contrast to Ppy-modified cells, the walls of unmodified yeast have wrinkled after 24h drying. The viability of yeast cells in the presence of different pyrrole concentrations has been evaluated.
authors.affiliation: Faculty of Chemistry, Department of Physical Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania; Laboratory of Bio-Nanotechnology, State Research Institute, Center for Physical Sciences and Technology, Savanoriu ave. 231, LT-01108 Vilnius, Lithuania. Electronic address: Arunas.Ramanavicius@chf.vu.lt.
authors.forename: Arunas
authors.initials: A
authors.lastname: Ramanavicius
authors.affiliation: Faculty of Chemistry, Department of Physical Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania; Laboratory of Bio-Nanotechnology, State Research Institute, Center for Physical Sciences and Technology, Savanoriu ave. 231, LT-01108 Vilnius, Lithuania.
authors.forename: Eivydas
authors.initials: E
authors.lastname: Andriukonis
authors.affiliation: Laboratory of Bio-Nanotechnology, State Research Institute, Center for Physical Sciences and Technology, Savanoriu ave. 231, LT-01108 Vilnius, Lithuania.
authors.forename: Arunas
authors.initials: A
authors.lastname: Stirke
authors.affiliation: Faculty of Chemistry, Department of Physical Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania; Laboratory of Bio-Nanotechnology, State Research Institute, Center for Physical Sciences and Technology, Savanoriu ave. 231, LT-01108 Vilnius, Lithuania.
authors.forename: Lina
authors.initials: L
authors.lastname: Mikoliunaite
authors.affiliation: Laboratory of Bio-Nanotechnology, State Research Institute, Center for Physical Sciences and Technology, Savanoriu ave. 231, LT-01108 Vilnius, Lithuania; Faculty of Electronics, Vilnius Gediminas Technical University, Sauletekio 11, LT-10223 Vilnius, Lithuania.
authors.forename: Zigmas
authors.initials: Z
authors.lastname: Balevicius
authors.affiliation: Laboratory of Bio-Nanotechnology, State Research Institute, Center for Physical Sciences and Technology, Savanoriu ave. 231, LT-01108 Vilnius, Lithuania; Nanotechnas-Center of Nanotechnology and Materials Science, Department of Analytical and Environmental Chemistry, Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania.
authors.forename: Almira
authors.initials: A
authors.lastname: Ramanaviciene
mesh_terms: D015374:Biosensing Techniques; D002473:Cell Wall / Q000378:metabolism; D055664:Electrochemical Techniques; D005292:Ferricyanides / Q000737:chemistry / Q000378:metabolism*; D018625:Microscopy, Atomic Force; D010084:Oxidation-Reduction; D019897:Periplasm / Q000378:metabolism; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D011758:Pyrroles / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013053:Spectrophotometry
chemical_list: D005292:Ferricyanides; D011108:Polymers; D011758:Pyrroles; C007931:hexacyanoferrate III; C067635:polypyrrole
keywords: Biofuel cells; Cell wall modification; Conducting polymers; Polypyrrole; Single cell based biosensors; Yeast cells