Fluorescence lifetime micro-endoscopy for in-vivo deep brain studies

In this project, we propose the development of a new imaging modality, which would facilitate submicrometre-scale observations of fluorescence lifetime in deep brain regions of living animals. Exploiting the principles of holographic endoscopy, we will introduce the prospect of Fluorescence Lifetime Imaging Microscopy (FLIM) through hair-thin multimode fibres. The minimally invasive FLIM endoscope will offer microenvironment-sensitive imaging, ideal for probing dynamic molecular processes within deep-brain structures. As an alternative to the traditional (time-domain) FLIM, we will exploit the frequency-domain (FD) approach, which mitigates dispersion effects within the optical geometry, while offering greatly accelerated image acquisition. An optimized optical geometry enabling simultaneous FD-FLIM and fluorescence micro-endoscopy will be developed and its performance will be evaluated ex vivo and in awake mice. This represents a significant leap forward in minimally invasive imaging, offering unprecedented insights into the intricate molecular mechanisms governing brain function.