Fluorescence lifetime microscopy – imaging the intrinsic fluorescence

Focus: 
Metrology in Life Sciences

In bio and food sciences a maximum of information within a cell is required at a minimum of interference, i.e. in vivo research should be performed without disturbing natural processes. In addition, the observations should be quantitative and the gained quantities independent of the applied investigation technique.

We use one-color (1c2p) and two-color-two-photon (2c2p) excitation of laser dyes, NAD(P)H, tryptophan and unlabeled proteins upon excitation around 400 and 800nm using the SHG and fundamental wavelength of a mode locked Ti:Sa femtosecond laser.

In combination with fluorescence lifetime and polarisation measurements this technique is optimal for “in vivo” investigations due to its very good intrinsic 3D resolution, large penetration depth, and especially its independence of fluorescence intensities. Beside the detection of pH or pO2 values, index of diffraction n, or Ca2+ concentrations (with a resolution of 300nm), melanin, NAD(P)H and tryptophan can be directly observed. A discrimination between free and enzyme bound species is possible on a quantitative level without using any calibration procedure. Spores will be analyzed using this technique to get a better understanding of the underlying molecular processes of sporulation.

Mentor/s: 
Gericke
Institution: 
TU Braunschweig
Status: 
in progress
Ph.D. student: 
Al-Hadhuri