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Aggregation of Poly( γ ‐benzyl L ‐glutamate)s Followed by Time‐Resolved Emission Anisotropy
Author(s) -
Pokorná Veronika,
Výprachtický Drahomír,
Pecka Jan
Publication year - 2001
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/1616-5195(20010701)1:5<185::aid-mabi185>3.0.co;2-m
Subject(s) - anthracene , tetrahydrofuran , fluorophore , fluorescence , chemistry , excited state , dimethylformamide , solvent , photochemistry , anisotropy , relaxation (psychology) , fluorescence anisotropy , organic chemistry , optics , psychology , social psychology , physics , nuclear physics
Syntheses of poly( γ ‐benzyl L ‐glutamate)s (PBLGs) labeled with various fluorophores (tryptophan, dansyl, and anthracene) having different molecular weights are reported. Association of PBLG chains was studied by time‐resolved emission anisotropy in the solvents supporting the aggregation process (1,4‐dioxane and tetrahydrofuran) and in N,N ‐dimethylformamide, where the aggregates were not formed. The influence of molecular weight and polymer concentration on PBLG association was studied as well. The limiting emission anisotropy ( r ∞ ) and rotational correlation times ( ϕ ) were determined. The chain relaxation dynamics were compared with the fluorescence lifetimes of the fluorophores and spectroscopically suitable labels were selected. Tryptophan was found to be an inconvenient fluorophore for the association study of PBLGs because of its short excited‐state lifetime. Dansyl and anthracene fluorophores, however, proved to be suitable labels for the chain dynamics study of PBLGs in solution. The mobilities of PBLG chains in 1,4‐dioxane were slower than those in tetrahydrofuran and N,N ‐dimethylformamide because of PBLG association in this solvent.