title: Imaging of epithelial tissue in vivo based on excitation of multiple endogenous nonlinear optical signals.
abstract: We demonstrate an integrated optical microscope to image the living epithelial tissue by simultaneously exciting multiple endogenous nonlinear optical signals. By employing the spectral lifetime detection capability, this technology provides a unique approach to sensing the fine structure, the protein distribution, and the cellular metabolism of epithelial tissue in vivo. In particular, we investigated the two-photon excitation fluorescence (TPEF) of tryptophan, an essential amino acid serving as the building block of protein. Our findings show that the TPEF of cellular tryptophan produces a good contrast to reveal the morphology of the epithelial cell layer, and the contrast can be further enhanced by applying low-concentration acetic acid.
authors.affiliation: Department of Electronic and Computer Engineering, Hong Kong University of Science and Technology,Clear Water Bay, Kowloon, Hong Kong, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Jianan Y
authors.initials: JY
authors.lastname: Qu
mesh_terms: D000818:Animals; D006224:Cricetinae; D004848:Epithelium / Q000473:pathology*; D005453:Fluorescence; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007089:Image Enhancement / Q000379:methods; D036641:Microscopy, Fluorescence, Multiphoton / Q000295:instrumentation / Q000379:methods*; D009243:NAD / Q000737:chemistry; D055095:Optics and Photonics; D017785:Photons; D014364:Tryptophan / Q000737:chemistry
chemical_list: D009243:NAD; D014364:Tryptophan