AVS 45th International Symposium
    Biomaterial Interfaces Group Tuesday Sessions
       Session BI-TuM

Paper BI-TuM10
XPS Analysis of Oligonucleotides for DNA Microarrays

Tuesday, November 3, 1998, 11:20 am, Room 326

Session: Biosensor-Biology Interface
Presenter: E.C. Carr, Hewlett-Packard
Authors: E.C. Carr, Hewlett-Packard
K.J. Luebke, Hewlett-Packard
S.M. Lefkowitz, Hewlett-Packard
N.M. Sampas, Hewlett-Packard
S.S. Laderman, Hewlett-Packard
E. Poon, Hewlett-Packard
Correspondent: Click to Email
In recent years, a vast amount of DNA sequence information has been provided by the Human Genome Project. To make intelligent and efficient use of this information requires new analytical techniques capable of massively parallel interrogation. Microarrays of DNA have emerged as one of the most promising molecular recognition technologies for high sensitivity, multiplex analysis of DNA. It has been demonstrated that specific sequences of DNA can be synthesized directly on a planar surface, however the density and fidelity of the resulting oligonucleotides are of primary importance to the effectiveness of the array. We have used X-ray Photoelectron Spectroscopy (XPS) to measure phosphorus signal, and thus nucleotide density, of oligonucleotides synthesized on a silylated glass surface. We derive a coupling yield for the attachment of each nucleotide in the sequence that is in good agreement with yield derived from optical transmittance of dye bound to the final nucleotide. Coupling yield measured by these techniques is consistent with that achieved in standard DNA synthesis on porous glass beads using cleavable linkage to the bead and High-Performance Liquid Chromatography for measurement. Issues associated with the accuracy of making quantitative measurements on microarrays using XPS will be discussed.