Fluorescence kinetics of tryptophan in a heterogeneous environment.

The potentially highly informative, but complex fluorescence decay of amino acids in protein is not fully understood and presents a barrier to understanding. Here we have tested a new and general approach to describing experimentally measured the fluorescence decay in a heterogeneous macroscopic sample. The decay parameters carry information on the features of the kinetics induced by the environment's heterogeneity. Bayesian interference demonstrated that the model fits well to the fluorescence decay of tryptophan in human serum albumin (HSA). The approach has the potential to accelerate photophysical research of heterogeneous media and, specifically, to solve a critical outstanding problem in interpreting protein fluorescence, paving the way to further progress in biomedical research.