Dresden 2009 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 17: Reaction-diffusion systems
DY 17.8: Vortrag
Mittwoch, 25. März 2009, 16:30–16:45, ZEU 118
Binding kinetics of DNA and protein targets to surface tethered probes studied with switchable DNA surfaces — •Makiko Maruyama, Wolfgang Kaiser, Erika Pringsheim, Gerhard Abstreiter, and Ulrich Rant — Walter Schottky Institut, Technische Universität München, 85748 Garching, Germany
We report on the binding kinetics of DNA and protein targets to surface immobilized probes, using the switchDNA sensor. The overall detection performance of a biosensor depends on the transport of target molecules from solution to the sensor and the reaction rate of the targets with the probes. The influence of analyte flow across the sensor surface and the sensor temperature on the binding response is studied and the results are compared to solution measurements.
The hybridization of 24nt DNA on the switchDNA sensor proceeds with outstanding efficiency; the rate constants obtained on the surface (k > 105 M−1s−1) correspond to values measured in solution. The results indicate that the sensor predominantly operates in the reaction-limited case for the DNA binding experiments, whereas diffusion-limited kinetics are found for the binding of streptavidin to surface-tethered biotinylated probes. The results can be rationalized by theoretically estimating the operation conditions of the sensor based on dimensionless fluidic numbers, in particular the Péclet and Damköhler numbers. The rapid reaction of the biotin-streptavidin couple (k > 5 × 106 M−1s−1 in solution) leads to the formation of a target-concentration depletion zone above the sensor surface and results in mass-transport limited kinetics.