Ruprecht-Karls-Universitšt Heidelberg

Fluorescence lifetimes


Fluoresence lifetimes of biological tissues can be observed upon excitation with laser pulses or periodical intensity variations. Several laboratories around the world currently investigate the potential for diagnostics, phototherapy and DNA chip analysis.

The aim of this project is to estimate fluorescence lifetimes using spatial regularization to reduce noise.


Fluorescence lifetimes measured in MCF7 breast-cancer cells. Receptors for the epidermal growth factor (EGF) hormone play an important role in the development of cancer tumors and are an important target for drug-development. EGF-receptors where tagged with a green fluorescent protein and incubated with a fluorescently labeled antibody that detects the activation state of the receptor. Binding of the antibody to the activated receptor is detected by fluorescence resonance energy transfer (FRET) between the green fluorescent protein and the tagged antibody, which reduces the fluorescence lifetime of the GFP. Low lifetime values (blue color-code, left cell) indicate a high degree of binding, and thereby show activation of the cancer cell by the hormone. The right cell has higher lifetime values (green color-code), showing a lower degree of activation by EGF.



Last update: 06.10.2010, 12:25
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