Imaging ellipsometry combined with surface plasmon resonance for real-time biospecific interaction analysis

We present imaging ellipsometry technique for kinetic measurement of bimolecular interactions with high sensitivity. When combined with surface plasmon resonance (SPR) effects, the ellipsometry becomes powerful technique for analyzing adsorption and desorption of biomolecules on gold layer based sensor chip surfaces. Because ellipsometric measurement gives ellipsometric parameters, namely Δ, that is very sensitive to surface layer changes. The SPR combined ellipsometry is realized by Kretschmann configuration SPR cell comprising with about 30-nm-thick gold film deposited on top of glass slides, SF10 glass prism, and flow injection system. We used nulling type of imagining ellipsometer to acquire two dimensional ellipsometric parameters with spatial resolution down to one micrometer. We present results of kinetic measurements of biotin-streptavidin interactions for custom-built sensor chip.