title: Synthesis and use of an in-solution ratiometric fluorescent viscosity sensor.
abstract: A procedure for the synthesis of a ratiometric viscosity fluorescent sensor is described in this protocol. The essential requirement for the design of this sensor is the attachment of a primary fluorophore that has both a viscosity-independent fluorescence emission (coumarin dye shown in blue) and an emission from a fluorophore that exhibits viscosity-dependent fluorescent quantum yield (p-amino cinnamonitrile dye shown in red). The use of sensor 1 in viscosity measurements involves solubilization in a liquid of interest and excitation of the primary fluorophore at lambda(ex) = 360 nm. The secondary fluorophore is simultaneously excited via resonance energy transfer. The ratio of the fluorescent emission of the secondary over the primary fluorophore provides a fast and precise measurement of the viscosity of the solvent. The synthesis of compound 1 using commercially available materials can be completed within 5 d.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Fischer
authors.forename: Emmanuel A
authors.initials: EA
authors.lastname: Theodorakis
authors.forename: Mark A
authors.initials: MA
authors.lastname: Haidekker
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003374:Coumarins / Q000737:chemistry; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D009570:Nitriles / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D014783:Viscosity
chemical_list: D003374:Coumarins; D005456:Fluorescent Dyes; D009570:Nitriles; C002599:cinnamonitrile