title: Increase of fluorescence anisotropy upon self-assembly in headgroup-labeled surfactants.
abstract: The change in fluorescence anisotropy upon micellization in headgroup-labeled surfactants is investigated. After eliminating the likelihood of depolarizing RET, anisotropy is shown to increase upon self-assembly due to increased rotational correlation times of the fluorophore. This is shown using two surfactant-fluorophore systems. Anisotropy in NBD-labeled phospholipids is studied both in chloroform (unaggregated) and in water (unilamellar vesicles), while in tryptophan-containing peptide-amphiphiles, the variation of anisotropy with concentration leads to a reasonable measurement of CAC. Anisotropy increase is shown to be largely the product of increased rotational correlation times for the fluorophore, relative to its tau. These results serve as a basis for future work that measures the amount of depolarizing energy transfer, characterizing distances between similar fluorescent headgroups on mixed micelles.
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA. mjk@engineering.ucsb.edu
authors.forename: Mark
authors.initials: M
authors.lastname: Kastantin
authors.forename: Badriprasad
authors.initials: B
authors.lastname: Ananthanarayanan
authors.forename: Brian
authors.initials: B
authors.lastname: Lin
authors.forename: Jan
authors.initials: J
authors.lastname: Ressl
authors.forename: Matthew
authors.initials: M
authors.lastname: Black
authors.forename: Matthew
authors.initials: M
authors.lastname: Tirrell
mesh_terms: D000595:Amino Acid Sequence; D005454:Fluorescence Polarization; D008823:Micelles; D015394:Molecular Structure; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D013501:Surface-Active Agents / Q000138:chemical synthesis* / Q000737:chemistry; D014364:Tryptophan / Q000737:chemistry
chemical_list: D008823:Micelles; D010455:Peptides; D013501:Surface-Active Agents; D014364:Tryptophan