Multifunctional Scanning Probe Technology
In recent years, we have pioneered the integration of scanning electrochemical microscopy (SECM) functionality into atomic force microscopy (AFM) tips enabling positioning of microelectrodes and nanoelectrodes, independent of the current response during simultaneous high resolution AFM imaging. AFM probes with integrated electrochemical sensing functionality provide a versatile tool for the inherent correlation of structural information with electrochemical surface activity at high lateral resolution. Microfabrication techniques in combination with focused ion beam (FIB) milling enable the reproducible integration of ultramicroelectrodes and nanoelectrodes into AFM tips, facilitating the integration of imaging amperometric biosensors, pH electrodes, and amalgam electrodes into AFM probes.
We have demonstrated that these advances extend the application of scanning force microscopy to cell biological applications adding correlated biochemical information on the investigated surface to the sample topology. Thereby, the investigation of complex biological processes and molecular biological interactions, e.g. at cell surfaces, is enabled providing simultaneous information on multiple parameters correlated in space and time. Furthermore, we have recently demonstrated the first combination of AFM with IR-ATR spectroscopy, which can easily be extended to AFM-SECM/IR-ATR.
Conventional SECM is currently applied to imaging applications with amalgam Au/Hg and Pt/Hg thin-film microelectrodes for dissolution and corrosion studies at metal oxides, and for the direct detection and identification of redox-protein activity after separation in two-dimensional (2-D) native gels.
Ongoing Projects:
- Combined atomic force scanning electrochemical microscopy (AFM-SECM) with bifunctional scanning probes
- Bifunctional AFM-SECM tip-integrated amperometric micro- and nano-biosensors for glucose, ATP, and hydrogen peroxide
- AFM-SECM with tip-integrated pH micro and nanosensors
- Imaging ATP release at epithelial cells with AFM-SECM
- AFM-SECM studies on dissimilatory metal reduction at microbe-mineral interfaces
- Combination of AFM with IR-ATR spectroscopy
- SECM imaging with amalgam ultramicroelectrodes
- SECM detection of redox-protein activity in native 2-D gels
