AVS 52nd International Symposium
    Applied Surface Science Monday Sessions
       Session AS+BI+NS-MoM

Paper AS+BI+NS-MoM4
Molecular Orientation Imaging with sub 10-nm Resolution by Vector Piezoresponse Force Microscopy

Monday, October 31, 2005, 9:20 am, Room 206

Session: Nanoscale Analysis: Biomaterial and Other Applications
Presenter: B.J. Rodriguez, North Carolina State University
Authors: B.J. Rodriguez, North Carolina State University
S. Jesse, Oak Ridge National Laboratory
A.P. Baddorf, Oak Ridge National Laboratory
A. Gruverman, North Carolina State University
S.V. Kalinin, Oak Ridge National Laboratory
Correspondent: Click to Email
Functional properties of calcified and connective tissues are determined by the relative ordering and orientation of a relatively small number of biopolymers, such as collagen. Here we present a new approach for local molecular orientation imaging in biological systems by Vector Piezoresponse Force Microscopy (Vector PFM). Vector PFM is capable of determining the local electromechanical activity and orientation in piezoelectric materials with a spatial resolution below 10 nm. The applicability of Vector PFM to biological systems is demonstrated for objects from butterfly wings to bones. Electromechanical characterization of enamel and dentin layers in human tooth is demonstrated. The vector electromechanical response of a bundle of collagen molecules in human tooth dentin has been visualized with 5 nanometer resolution. A method for imaging the local orientation of biomolecules from Vector PFM data has been illustrated using collagen molecules embedded in a hydroxyapatite matrix. As another example, 2D piezoelectric properties and local elasticity of a butterfly wing are measured with nanoscale resolution and interpreted in terms of the relative orientation of chitin molecules in the wing scales. The ubiquitous presence of electro-activity in biopolymers, such as chitin, keratin, collagen, and cellulose, suggests that Vector PFM has exceptional potential for orientation imaging of biological materials on the sub-10 nanometer length scale. Research was sponsored by the U.S. Department of Energy, under contract DE-AC05-00OR22725 with UT-Battelle, LLC and by the National Science Foundation grant DMR-0072998 (AG). Research partially performed as a Eugene P. Wigner Fellow (SVK).