Biointerface ellipsometry

In this project, the In Situ Spectroscopy group investigates biofunctional interfaces and develops infrared spectroscopy methods to analyse these interfaces. The employed polarisation-dependent techniques, such as IR ellipsometry and IR polarimetry, are sensitive label-free and non-destructive methods for a fast, spatially resolved detection. The group employs their methodical expertise to develop new biosensor concepts – especially in combining the methods with brilliant radiation sources or lasers. Important applications for the developed techniques are biochips for diagnostics and pharmaceutical research.

One key part of the project concerns nano- and microstructured functional surfaces and layers as well as their investigation via polarisation-dependent IR microscopy. The group especially works on the investigation of structure and interaction in organic layers, hybrid layers, and biofunctional layers as well as on the detection of growth processes on their surfaces. Developing optical models and enhancing the methods towards ellipsometric microscopy creates access to new measurement categories and to quantitative analysis. Biologically relevant samples are often available in very small sample sizes of only a few microliters, and multidisciplinary analytical processes often are ill suited for small quantities. To improve small sample analysis, the group establishes monolayer-sensitive measurements for IR microscopy with microliter and microfluidic cells.

Due to the high technological interest for novel detection methods, sensors, and functional templates for biotechnological approaches, the analysis of functional surfaces and films becomes more and more important. Therefore, the In Situ Spectroscopy group concentrates on developing suitable optical methods that enable the detection of biomolecules as well as the investigation of binding events and specific adsorption mechanisms on biohybrid surfaces. These methods are used to characterise new materials such as polymers, polymer hybrids (for example polymer brushes), and enhancement substrates for nanobiotechnology and medical technology.