Characterization of DNA immobilization and subsequent hybridization on a 2D arrangement of streptavidin on a biotin-modified lipid bilayer supported on SiO2.

We show how the water content (and effective density) of thin adsorbed films composed of biomolecules can be determined using combined quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR) analysis. In particular, these techniques, combined with theoretical treatment using a Voigt-based viscoelastic model, were applied to analyze the state of surface immobilized single stranded biotin-modified probe DNA (b-DNA) coupled via streptavidin to a biotin-doped supported phospholipid bilayer (b-SPB)). From a proper analysis, it is demonstrated how changes in effective thickness, delta(f), and the viscoelastic components (shear viscosity, eta(f), and shear elasticity, mu(f))) can be obtained during both DNA immobilization and hybridization with single stranded fully complementary target DNA. In particular, it is demonstrated how this type of analysis can be used to control the state of streptavidin arrangement for improved measurements of DNA hybridization kinetics. The latter is demonstrated by identifying a surface-coverage dependent viscoelastic behavior of immobilized b-DNA, which is shown to influence the hybridization efficiency.