AVS 58th Annual International Symposium and Exhibition
    Applied Surface Science Division Wednesday Sessions
       Session AS+BI+NS-WeM

Paper AS+BI+NS-WeM9
Determination of Molecular Polarization at Protein-Electrode Interfaces with Combined Optical, Transport, and Dielectric Scanning Probe Microscopy

Wednesday, November 2, 2011, 10:40 am, Room 102

Session: Advances in Scanning Probe Microscopy
Presenter: Xi Chen, University of Pennsylvania
Authors: X. Chen, University of Pennsylvania
K. Kathan-Galipeau, University of Pennsylvania
B.M. Discher, University of Pennsylvania
D.A. Bonnell, University of Pennsylvania
Correspondent: Click to Email
Bio-molecule integrated electronic devices are of great interest recently. For such systems to be designed and fabricated, the optoelectronic properties of protein molecules in ambient environment must be understood at a fundamental level. Here we demonstrate a new scanning probe based technique: torsional resonance nanoimpedence microscopy (TR-NIM), which simultaneously probes transport and dielectric properties in conjunction with optical excitation. To make a controlled interface, we start by designing a peptide molecule with ability to control protein/electrode interface interactions, as well as incorporation of several different optically active cofactors, and we successfully patterned peptides on HOPG substrates. Using TR-NIM electronic transport and the effect of optical absorption on dielectric polarizability in oriented peptide single or multiple molecular layers is determined. This approach enables quantitative comparisons of the change in polarization volume between the ground state and excited state in both single and multiple molecular layers.