AVS 47th International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI+NS-ThA

Paper BI+NS-ThA4
Fluorescence Detection of Surface DNA Hybridization Reactions Based on Surface Structural Changes

Thursday, October 5, 2000, 3:00 pm, Room 202

Session: Biosensors
Presenter: T.H. Huang, National Institute of Standards and Technology
Authors: T.H. Huang, National Institute of Standards and Technology
S.J. Stranick, National Institute of Standards and Technology
M.J. Tarlov, National Institute of Standards and Technology
Correspondent: Click to Email
We describe a novel fluorescence method for the detection of surface-immobilized DNA hybridization reactions. Solid phase hybridization reactions form the basis of DNA chip technologies that are used for sequencing and genetic diagnostic applications. In conventional fluorescence-based detection schemes, the "target" DNA is typically labeled with a fluorophore. We report a method where instead, the "probe" DNA is labeled with a fluorophore. Our model surface hybridization system uses a mixed monolayer of fluorescein-tagged, thiol-derivatized, single-stranded DNA probes and 6-mercaptohexanol self-assembled on Au surfaces. Prior to hybridization, the fluorophore on the probe is in closer proximity to the gold surface, resulting in greater quenching of the fluorescence signal. Upon hybridization, the double-stranded DNA adopts a rod-like structure that extends the fluorophore away from the gold surface. With the fluorphores located further from the gold surface, quenching is reduced and an increase in fluorescence intensity is observed. Parameters affecting fluorescence intensity such as probe surface coverage, probe length, and target concentration will be discussed. In addition, a comparison of probe- and target-labeled fluorescence detection schemes will be made.