Spectroscopic ellipsometry characterisation of Streptavidin Alexa binding to PLL-g-PEGbiotin(50%)

We characterized the functionalization of glass platforms with PLL-g-PEGbiotin(50%) and Streptavidin Alexa 555 (SAvAlexa) by spectroscopic ellispometry to obtain the precise surface mass density of both molecules. We used a SE (RC2, J.A. Woollam, USA) on auxiliary silicon wafers covered with 60 nm thermal SiO2. Molecules were injected one after the other into the liquid chamber (500 µl liquid cell, J.A. Woollam) and analysed in dynamic mode by SE. At saturation PLL-g-PEGbiotin50% adsorbed with 119.8 ± 9.2 ng/cm2 and SAvAlexa with 246.3 ± 36.4 ng/cm2. The experiment has been repeated 3 times and in the excel sheet here uploaded all the dynamic data of thickness (n_Biofilm), refractive index (A_Biofilm) and area mass density are reported for the PLL-g-PEGbiotin(50%) layer and for the SAvAlexa are reported.