ABSTRACT

Intrinsic uorophores and their associated biological processes exhibit dynamics on a wide range of timescales throughout the heterogeneous milieu of living cells. Conventional time-lapse autouorescence intensity imaging is best suited for monitoring slow physiological functions such as changes in cellular morphology, cell migration, and intracellular distribution that take place on a timescale of seconds to minutes. In contrast, ultrafast (10−12-10−7 s) time-resolved uorescence measurements can probe molecular dynamics, such as excited-state processes and rotational dynamics, which are acutely sensitive to the chemical structure, intermolecular interactions, and microenvironment of a given uorophore. Time-resolved uorescence and anisotropy measurements are uniquely suited for a detailed

5.1 Introduction ......................................................................................107 5.2 eoretical Background...................................................................109