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Disputation Johannes Stellmacher

12.03.2021 | 13:00
Thema der Dissertation:
Time-resolved fluorescence spectroscopic and microscopic investigation of biological barriers and nanosized drug delivery systems
Abstract: Fluorescence lifetime imaging (FLIM) is of particular interest for life sciences as it is able to visualize endogenous and exogenous fluorophores on the subcelluar and even suborganelle level. It is mostly independent of fluorophore concentration and optical loss in the sample while being sensitive to the local environment and reliably reports on physicochemical parameters like local pH, viscosity, or reactive oxygen species. Furthermore, fluorescent molecular rotors are fluorophores, which can be used to sense local nanoviscosity using their fluorescence lifetime. In living cells of the gastrointestinal tract, they were used to map the 3D viscosity profile of the mucus layer lining the small intestine and characterize this diffusion barrier with unprecedented precision and spatial resolution. The extracted gradients and heterogeneities of the mucin network were compared based on culturing circumstances of the mucus producing epithelial cells, setting a framework for physiological cell growing conditions.
Additionally, a novel platform for labeling biomolecules with a fluorophore and a spin label was developed. The multiplexed read-out of FLIM and EPR data facilitates the simultaneous determination of spatially resolved target molecule concentration and characterization of its immediate environment while avoiding analytical inconsistencies resulting from individual labeling.
In this talk, I demonstrate the capabilities of time-resolved fluorescence techniques when paired with proper analytical strategies for the application in biophysical research and the development of new drug delivery systems.

Zeit & Ort

12.03.2021 | 13:00