Fluorescence polarization spectroscopy and time-resolved fluorescence kinetics of native cancerous and normal rat kidney tissues

Abstract

Steady state fluorescence polarization spectra and time-resolved emission decay kinetics have been measured in vitro from malignant and normal rat kidney tissue. The degrees of polarization and emission lifetimes from the cancerous and normal systems are different. The spectroscopic differences are attributed to environmental transformations local to the native flavin and porphyrin fluorophors' binding sites.

Study of rotational dynamics of receptor-targeted contrast agents in cancerous and normal prostate tissues using time-resolved picosecond emission spectroscopy

“…The experimental arrangement of the time-resolved fluorescence measurements has been reported elsewhere [3]. Ultrafast 130 fs laser pulses at 800 nm were generated with a repetition rate of 82 MHz from a mode-locked Ti:sapphire laser system and used to pump the samples (Cybesin-and Cytate-stained cancerous or normal prostate tissues).…”

“…The time-resolved polarization measurements of fluorophores excited with linearly polarized light can be applied as a probe to determine the rotation rate of dye molecules, which is a function of the viscosity and temperature of the environment, and the size of rotating molecule [13]. The ultrafast rotation dynamics of fluorophores can be used to extract the information of the surrounding medium [3]. The fluorescence depolarization property is usually described by the time-resolved fluorescence anisotropy, defined as [13,14]:…”

“…Inspired by the initial research of Alfano's group in the 1980s [2], fluorescence spectroscopy has been widely studied as an optical tool for cancer diagnosis. Time-resolved fluorescence polarization spectroscopy measures the temporal intensity profile and degree of emission polarization within its lifetime, and it provides information not only of the location of abnormalities but also their biophysical microenvironments [3,4]. The use of intrinsic chromophores to differentiate optical properties of diseased and healthy human tissues is limited by their ultraviolet bands [5], which are not in the near-infrared (NIR) range of "tissue optical window" [6].…”

“…The advantages of optical receptor-targeted contrast agents include a high affinity of specific 0003-6935/11/101312-11$15.00/0 © 2011 Optical Society of America ligand corresponding to overexpressed receptor for the localization of tumors [7], rapid clearance of the applied contrast, possibilities of preparing a library of peptides for rapid identification of bioactive molecules [7], and preservation of spectral advantage in the NIR range of the "tissue optical window" [10,11]. Time-resolved polarization-dependent fluorescence spectroscopy provides not only the intensity information but also relaxation and rotation information of fluorophores in the microenvironment of media [3]. Gleason grades for prostate cancer stages indicate that there are different microstructures of cancerous prostate tissue in comparison with normal prostate tissue: high cell density, nonuniform cell distribution, and enlarged nuclei size in cancerous tissue [12].…”

Fluorescence investigations to classify malignant laryngeal lesions in vivo

“…In those studies, both endogenous tissue autofluorescence [1][2][3][4][5][6][7] and fluorescence of a tumor-marking agent have been investigated. 8,9 Several groups have also studied the fluorescence from lesions in the head and neck region.…”