title: Fluorescence lifetime imaging of endogenous biomarker of oxidative stress.
abstract: Presence of reactive oxygen species (ROS) in excess of normal physiological level results in oxidative stress. This can lead to a range of pathological conditions including inflammation, diabetes mellitus, cancer, cardiovascular and neurodegenerative disease. Biomarkers of oxidative stress play an important role in understanding the pathogenesis and treatment of these diseases. A number of fluorescent biomarkers exist. However, a non-invasive and label-free identification technique would be advantageous for in vivo measurements. In this work we establish a spectroscopic method to identify oxidative stress in cells and tissues by fluorescence lifetime imaging (FLIM). We identified an autofluorescent, endogenous species with a characteristic fluorescent lifetime distribution as a probe for oxidative stress. To corroborate our hypothesis that these species are products of lipid oxidation by ROS, we correlate the spectroscopic signals arising from lipid droplets by combining FLIM with THG and CARS microscopy which are established techniques for selective lipid body imaging. Further, we performed spontaneous Raman spectral analysis at single points of the sample which provided molecular vibration information characteristics of lipid droplets.
authors.affiliation: Laboratory of Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine.
authors.forename: Rupsa
authors.initials: R
authors.lastname: Datta
authors.affiliation: Department of Biomedical Engineering, University of California, Irvine.
authors.forename: Alba
authors.initials: A
authors.lastname: Alfonso-García
authors.affiliation: Department of Developmental &Cell Biology, University of California, Irvine.
authors.forename: Rachel
authors.initials: R
authors.lastname: Cinco
authors.affiliation: Laboratory of Fluorescence Dynamics, Department of Biomedical Engineering, University of California, Irvine.
authors.forename: Enrico
authors.initials: E
authors.lastname: Gratton
mesh_terms: D052436:Adipose Tissue, White / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000378:metabolism / Q000473:pathology; D003920:Diabetes Mellitus / Q000378:metabolism / Q000473:pathology; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D019301:Oleic Acid / Q000494:pharmacology; D061848:Optical Imaging; D018384:Oxidative Stress / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000737:chemistry / Q000378:metabolism
chemical_list: D015415:Biomarkers; D017382:Reactive Oxygen Species; D019301:Oleic Acid