User:
Jianghong Rao, Assistant Professor in Radiology, Stanford University
Project:
Examining protease involvement in tumor metastasis and cell migration
Problem:
To look at deep tissue with standard fluorescent molecular labels, the light that stimulates the fluorescence must penetrate through tissue that strongly absorbs and scatters light. Then, when those same molecules emit light, the emission must travel through that same tissue mass, where it also will be absorbed and will scatter.
Solution:
Rao adapted a method called bioluminescence resonance energy transfer (BRET) for imaging deep in the tissue. Instead of using energy from excitation light provided from outside the organism, BRET relies on bioluminescent luciferase to provide energy right at the surface of the fluorescent labels. Normally, researchers using BRET conjugate the luciferase with fluorescent proteins, which absorb the bioluminescence and re-emit its light at a longer wavelength. Light from these BRET conjugates is still absorbed and scattered so strongly, ...
