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    Biomaterials Monday Sessions
       Session BI-MoM

Paper BI-MoM4
Self-Assembly of Modified Porphyrin Monolayers

Monday, October 29, 2001, 10:40 am, Room 102

Session: Molecular Recognition
Presenter: A.L. Bramblett, University of Washington
Authors: A.L. Bramblett, University of Washington
M.S. Boeckl, University of Washington
K.D. Hauch, University of Washington
T. Sasaki, University of Washington
J.W. Rogers, Jr., Pacific Northwest National Laboratory
B.D. Ratner, University of Washington
Correspondent: Click to Email
Assembled monolayers can be used to deliver recognition signals to biological systems. Planar, multi-ring porphyrin structures can provide precision lateral control of chemistry at interfaces. Porphyrin molecules, which have peripheral constituents with the ability to hydrogen bond or coordinate to a metal, are predicted to form ordered molecular monolayers on gold surfaces in a side-by-side orientation. TPyP-Ge-Disulfide (a Ge coordinated pyridyl substituted porphyrin with two disulfide ligands) has been synthesized for use in self-assembling porphyrin monolayers, which form when one of two disulfide ligands binds to the gold surface. Self-assembled monolayers of TPyP-Ge-disulfide have been prepared on gold for characterization. X-ray photoelectron spectroscopy (XPS) of TPyP-Ge-disulfide shows that the atomic composition of the surface is consistent with a porphyrin monolayer, and approximately 50% of the sulfur atoms are bound to gold. Further, ultraviolet-visible spectroscopy (UV/Vis) shows a red shift in the peak of the Soret band, which is indicative of side-by-side porphyrin orientation when self-assembled. @footnote 1@ In addition, monolayers formed utilizing hydrogen bonding between the TPyP-Ge-disulfide and TCP (benzoic acid derivatized porphyrin), or utilizing Zn@super 2+@ coordination with the pyridyl nitrogen in TPyP-Ge-disulfide will be characterized using XPS, UV/Vis, and scanning tunneling microscopy, to examine the porphyrin arrangement on the gold surface. By chemically modifying the remaining free disulfide bond, these monolayers could be used to present biological ligands of interest in a spatially controlled manner. @FootnoteText@ @footnote 1@ Boeckl, M. S.; Bramblett, A. L.; Hauch, K. D., Sasaki, T.;Ratner, B. D.; Rogers, Jr, J. W. Langmuir 2000, 16, 5644-5653