Surface Plasmon Resonance Measurements of DNA Probe/Target
Hybridization Reactions on Gold Surfaces

Geoffrey B. Saupe and Michael J. Tarlov
Process Measurements Division,  NIST

Optimizing and understanding the parameters involved in thin film DNA hybridizations are important to emerging DNA sensor array technologies. We recently constructed a Surface Plasmon Resonance (SPR) instrument and software for measuring the small refractive index changes, and hence mass changes, that are involved during monolayer DNA hybridization events. A model system of DNA attached to gold surfaces has been developed for this work and is ideally suited for study by SPR techniques. Short sequences of single-stranded DNA, so-called ssDNA probes, are end-tethered to gold surfaces through a thiol linker. Complementary ssDNA targets in solution can hybridized to the surface bound probes. We are studying how variations in probe surface structure and sequence of ssDNA target affect hybridization rates and efficiencies.