AVS 50th International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThM

Paper BI-ThM3
Simultaneous Electrochemical and Tapping Mode Imaging of Soft Biological Samples with AFM Tip Integrated Nanoelectrodes and Nanobiosensors

Thursday, November 6, 2003, 9:00 am, Room 318/319

Session: Biosensors
Presenter: A. Kueng, Georgia Institute of Technology
Authors: A. Kueng, Georgia Institute of Technology
C. Kranz, Georgia Institute of Technology
A. Lugstein, Vienna University of Technology, Austria
E. Bertagnolli, Vienna University of Technology, Austria
B. Mizaikoff, Georgia Institute of Technology
Correspondent: Click to Email
Recent developments in combined scanning probe techniques are aiming at complementary, simultaneously mapped information on physical and chemical surface properties with high spatial resolution. The integration of micro and nanoelectrodes into AFM tips using micromachining and focused ion beam (FIB) techniques recently described by our research group@footnote 1,2@ enables to simultaneously obtain laterally resolved electrochemical information at the sample surface during tapping mode AFM imaging. A defined geometry of an electroactive surface integrated above the very end of the original AFM tip allows direct correlation of the current signal and the topographical information. Hence, the functionality of scanning electrochemical microscopy (SECM) can be integrated into AFM. The presented technology enables integration of potentiometric electrodes or micro-/nanobiosensors providing simultaneous in-situ information on bioactive processes at the sample surface during AFM imaging. Due to the achieved current-independent positioning of the integrated electrode, biosensor functionality can be realized by modification of the electrode surface with an enzyme receptor, such as peroxidase or glucoseoxidase. Furthermore, bifunctional probes are applied to simultaneously image topographical and electrochemical properties of biologically active sample surfaces in AFM tapping mode. The activity of an oxidoreductase immobilized into a periodic micro-pattern of a soft polymer matrix is electrochemically detected during AFM imaging in tapping mode. For the first time specific detection of a molecular product resulting from enzymatic substrate conversion was obtained during AFM imaging. @FootnoteText@ @footnote 1@ C. Kranz, G. Friedbacher, B. Mizaikoff, A. Lugstein, J. Smoliner, E. Bertagnolli, Anal. Chem., 73, 2491-2500 (2001). @footnote 2@ A. Kueng, C. Kranz, B. Mizaikoff, A. Lugstein, E. Bertagnolli, Appl. Phys. Lett., 82, 1592-1594 (2003).