AVS 46th International Symposium
    Biomaterial Interfaces Group Monday Sessions
       Session BI-MoM

Paper BI-MoM2
Characterization and Quantitation of DNA on Gold

Monday, October 25, 1999, 8:40 am, Room 613/614

Session: Biosensor-Biology Interface
Presenter: A.B. Steel, Gene Logic, Inc.
Authors: A.B. Steel, Gene Logic, Inc.
R.L. Levicky, Columbia University
T.M. Herne, National Institute of Standards and Technology
M.J. Tarlov, National Institute of Standards and Technology
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The interaction of DNA with gold has been characterized using a number of analytical techniques. The role of structural aspects of oligonucleotides, 8 to 48 nucleotide strands, on immobilization on gold has been investigated using electrochemistry, phosphorimaging, FT-IR spectroscopy, and neutron reflectivity. The value of incorporating a substrate-specific binding group was confirmed. In the case of binding to gold, the substrate-specific group is a thiol (SH). The packing density was studied as a function of the oligonucleotide length. The packing density is roughly constant for oligonucleotide segments less than 16 nucleotides in length. Longer strands pack on the surface at a density that is inversely proportional to the number of nucleotides in the segment. The data suggests that the conformation of single-stranded DNA transitions from a 'rigid rod' to a 'flexible coil' near this 16 nucleotide segment length.