Combined Atomic Force Scanning Electrochemical Microscopy
National Science Foundation (NSF);
Principle Investigator: Dr. B. Mizaikoff;
"Multifunctional Scanning Probes for In-Situ Analysis of Chemical Processes at Microbe/Mineral Interfaces"
Project Duration: 2002-2006
Selected Related Publications
This project focuses on the development of multifunctional scanning micro- and nanoprobes (e.g. combined AFM-SECM) and scanning probe tip integrated electrochemical sensors (pH sensor; amalgam electrode) for investigating microbe-mineral interfaces. The systems biological focus of this project is to fundamentally elucidate the reductive metal (Fe3+, Mn2+) respiration mechanisms of Shewanella oneidensis and putrefaciens.
All studies are performed in a cross-disciplinary team of Co-PIs at Georgia Tech: Dr. C. Kranz (School of Chemistry and Biochemistry), Dr. P. Hesketh (School of Mechanical Engineering), Dr. A. Fedorov (School of Mechanical Engineering), Dr. T. DiChristina (School of Biology), and Dr. M. Taillefert (School of Earth and Atmospheric Sciences).
The bioavailability and in-situ detection of dissolved chemical species such as Fe2+, Fe3+, and S2O32- is attracting increasing interest for understanding the environmental and geological chemical reactions at the microbe-mineral interface. A versatile and promising tool for the investigation of trace metal distributions at a microscopic scale is scanning electrochemical microscopy (SECM) in combination with square wave voltammetry (SWASV). Recently, we succeeded in using platinum/mercury amalgam microelectrodes for the direct detection of species with negative reduction potentials, including Mn2+, Fe2+, O2, and sulfur species. The developed amalgam microelectrodes in combination with SECM were applied as a read-out and identification mechanism of iron-reducing proteins separated in native gels enabling the laterally resolved quantitative determination of the microbial reductive dissolution of iron citrate above a microbial protein band in a gel buffered at mildly acidic conditions.
Selected Related Publications:
- C. Kranz, G. Friedbacher, B. Mizaikoff, A. Lugstein, J. Smoliner, E. Bertagnolli, Integrating an Ultramicroelectrode in an AFM Cantilever. Combined Technology for Enhanced Information, Anal. Chem., 73, 2491-2500, 2001.
- A. Lugstein, E. Bertagnolli, C. Kranz, B. Mizaikoff, Fabrication of a Ring-Nanoelectrode Integrated in an AFM-Tip -- A Novel Approach Towards Simultaneous Electrochemical and Topographical Imaging, Surf. and Interf. Anal., 33, 146-150, 2002.
- D. Rudolph, C. Kranz, S. Neuhuber, M. Taillefert, B. Mizaikoff, Scanning Electrochemical Microscopy Imaging of Rhodocrosite Dissolution Using Gold Amalgam Electrodes, Analyst, 129, 443-448, 2004.
- O. Skylar, A. Kueng, C. Kranz, B. Mizaikoff, A. Lugstein, E. Bertagnolli, G. Wittstock, Numerical Simulation of SECM Experiments with Frame-Shaped Integrated AFM-SECM Probes Using the Boundary Element Method, Anal. Chem., 77, 502-510, 2005.
- D. Rudolph, D. Bates, T. DiChristina, C. Kranz, B. Mizaikoff, Detection of Metal-Reducing Enzyme Complexes by Scanning Electrochemical Microscopy, Nature Methods, in preparation, 2005.
