title: Detection of radicals in single droplets of oil-in-water emulsions with the lipophilic fluorescent probe BODIPY(665/676) and confocal laser scanning microscopy.
abstract: Lipid oxidation is a widespread phenomenon in foods and other systems of biological origin. Detection methods for early stages of lipid oxidation are in demand to understand the progress of oxidation in space and time. The fluorescence spectrum of the nonpolar fluorescent probe BODIPY(665/676) changes upon reacting with peroxyl radicals originating from 2,2'-azobis(2,4-dimethyl)valeronitrile and tert-butoxyl radicals generated from di-tert-butylperoxide. The excitation wavelength of the main peak of BODIPY(665/676) was 675 nm in the fluorometer, and 670 nm under the microscope, and the optimum excitation wavelength for the secondary peak of BODIPY(665/676) was 580 nm. Advantages of using BODIPY(665/676) are fewer problems with autofluorescence and the possibility of combining several fluorescent probes that are excited and emitted at lower wavelengths. However, because of the spectrum of the probe, specific lasers and detectors are needed for optimal imaging under the microscope. Furthermore, BODIPY(665/676) is resistant to photobleaching at both excitation wavelengths, 670 and 580 nm. In diffusion studies, BODIPY(665/676) is highly lipophilic, remaining in the lipid phase and not diffusing into the aqueous phase or between lipid droplets.
authors.affiliation: Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark.
authors.forename: Piret
authors.initials: P
authors.lastname: Raudsepp
authors.affiliation: Faculty of Life Sciences, Rhine-Waal University of Applied Sciences, 47533 Kleve, Germany; Max Rubner Institute, D-95326 Kulmbach, Germany. Electronic address: dagmarAdeline.brueggemann@hochschule-rhein-waal.de.
authors.forename: Dagmar A
authors.initials: DA
authors.lastname: Brüggemann
authors.affiliation: Department of Food Science, University of Copenhagen, DK-1958 Frederiksberg C, Denmark.
authors.forename: Mogens L
authors.initials: ML
authors.lastname: Andersen
mesh_terms: D001896:Boron Compounds / Q000737:chemistry; D004655:Emulsions; D005456:Fluorescent Dyes / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006801:Humans; D066292:Lipid Droplets / Q000737:chemistry; D015227:Lipid Peroxidation / Q000235:genetics*; D018613:Microscopy, Confocal; D010084:Oxidation-Reduction; D013050:Spectrometry, Fluorescence
chemical_list: D001896:Boron Compounds; D004655:Emulsions; D005456:Fluorescent Dyes; D005609:Free Radicals; C409489:bodipy 665-676
keywords: BODIPY(665/676); CLSM; Emulsion; Free radicals; Oxidation