title: Imaging Endogenous Bilirubins with Two-Photon Fluorescence of Bilirubin Dimers.
abstract: On the basis of an infrared femtosecond Cr:forsterite laser, we developed a semiquantitative method to analyze the microscopic distribution of bilirubins. Using 1230 nm femtosecond pulses, we selectively excited the two-photon red fluorescence of bilirubin dimers around 660 nm. Autofluorescences from other endogenous fluorophores were greatly suppressed. Using this distinct fluorescence measure, we found that poorly differentiated hepatocellular carcinoma (HCC) tissues on average showed 3.7 times lower concentration of bilirubins than the corresponding nontumor parts. The corresponding fluorescence lifetime measurements indicated that HCC tissues exhibited a longer lifetime (500 ps) than that of nontumor parts (300 ps). Similarly, oral cancer cell lines had longer lifetimes (>330 ps) than those of nontumor ones (250 ps). We anticipate the developed methods of bilirubin molecular imaging to be useful in diagnosing cancers or studying the dynamics of bilirubin metabolisms in live cells.
authors.affiliation: ∥3D Printing Medical Research Center, China Medical University Hospital, Taichung City 40447, Taiwan.
authors.forename: Yu-Fang
authors.initials: YF
authors.lastname: Shen
authors.forename: Ming-Rung
authors.initials: MR
authors.lastname: Tsai
authors.forename: Shao-Chieh
authors.initials: SC
authors.lastname: Chen
authors.forename: Yun-Shiuan
authors.initials: YS
authors.lastname: Leung
authors.forename: Chien-Tai
authors.initials: CT
authors.lastname: Hsieh
authors.forename: Yu-Shing
authors.initials: YS
authors.lastname: Chen
authors.forename: Fu-Lien
authors.initials: FL
authors.lastname: Huang
authors.forename: Rofeamor P
authors.initials: RP
authors.lastname: Obena
authors.forename: Medel Manuel L
authors.initials: MM
authors.lastname: Zulueta
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Huang
authors.forename: Wen-Jeng
authors.initials: WJ
authors.lastname: Lee
authors.forename: Kuo-Chun
authors.initials: KC
authors.lastname: Tang
authors.forename: Chun-Ta
authors.initials: CT
authors.lastname: Kung
authors.affiliation: ¶Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei 10051, Taiwan.
authors.forename: Min-Huey
authors.initials: MH
authors.lastname: Chen
authors.affiliation: ◆Institute of Oral Medicine, National Cheng-Kung University, Tainan 70101, Taiwan.
authors.forename: Dar-Bin
authors.initials: DB
authors.lastname: Shieh
authors.forename: Yu-Ju
authors.initials: YJ
authors.lastname: Chen
authors.forename: Tzu-Ming
authors.initials: TM
authors.lastname: Liu
authors.forename: Pi-Tai
authors.initials: PT
authors.lastname: Chou
authors.forename: Chi-Kuang
authors.initials: CK
authors.lastname: Sun
mesh_terms: D001663:Bilirubin / Q000032:analysis* / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000737:chemistry / Q000175:diagnosis; D045744:Cell Line, Tumor; D019281:Dimerization; D006801:Humans; D008099:Liver / Q000737:chemistry / Q000473:pathology; D008113:Liver Neoplasms / Q000737:chemistry; D036641:Microscopy, Fluorescence, Multiphoton; D025202:Molecular Diagnostic Techniques; D009062:Mouth Neoplasms / Q000175:diagnosis
chemical_list: D001663:Bilirubin