Internal dynamics of macromolecules probed quantitatively by pyrene excimer fluorescence
Dr. Jean Duhamel
Thursday, November 13, 2014
EIT 2053 (Main Link Room)
Abstract: The measurement of the rate constant <k> of excimer formation between two pyrene labels covalently attached onto a macromolecule has long been recognized to be a powerful means to gain information about the internal dynamics of macromolecules. However, the vast majority of reports found in the scientific literature provide quantitative information about <k> only when the macromolecule is labeled at two specific positions separated by a well-defined chain length. In effect, this stringent requirement limits these experiments to monodisperse chains end-labeled with pyrene. Work from this laboratory has dramatically expanded the scope of these experiments which can now be applied to any macromolecular architecture and labeling strategy. This presentation will describe how careful global analysis of time-resolved fluorescence decays acquired for the monomer and excimer of pyrene-labeled macromolecules with the Fluorescence Blob Model and Model Free Analysis (MFA) provides quantitative information about the internal dynamics of any pyrene-labeled macromolecule. The use of pyrene excimer formation to determine <k> allows one to compare the internal dynamics of a given family of pyrene-labeled macromolecule with others. It provides general trends that any pyrene-labeled macromolecule must obey, thus providing a means to eliminate artefacts. In this particular presentation, the internal dynamics of pyrene-labeled dendrimers and polymeric bottle brushes will be characterized using the MFA.