| Abstract
| - Simultaneous quartz crystal microbalance with dissipationmonitoring (QCM-D) and surface plasmon resonance(SPR) measurements are used to analyze the surfacekinetics of two biomacromolecular systems, one lipid andone protein based, undergoing surface-induced conformational changes. First we establish a theoretical platform, which allows quantitative analysis of the combinedSPR and QCM-D data. With this theoretical base, newinformation can be extracted, not obtainable with eithertechnique alone. As an example we demonstrate howtime-resolved measurements with these two techniquesin combinationyielding three independent measuredquantitiesadd new information about (i) kinetics, i.e.number of adsorbed molecules per unit area versus time,and (ii) temporal variation in the mass fraction of coupledwater versus coverage. In particular, it is demonstratedfor the first time, how the kinetics of the process duringwhich adsorbed vesicles are spontaneously transformedinto a supported phospholipid bilayer (SPB) on SiO2 canbe quantitatively separated into its two dominatingstates: adsorbed vesicles and supported planar bilayerpatches. In addition, the relevance of dynamically coupledwater for interpretation and modeling of the QCM-Dresponse during bilayer formation is discussed andfurther illustrated with a second model system: streptavidin adsorption on a biotin-modified SPB. A very strongcoverage dependence in the number of water moleculesper protein sensed by the QCM is demonstrated, withstrong implications for the use of QCM as a tool forquantitative determination of protein mass uptake kinetics.
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