title: Native Fluorescence and Time Resolved Fluorescence Spectroscopic Characterization of Normal and Malignant Oral Tissues Under UV Excitation--an In Vitro Study.
abstract: The present work aims to investigates the native fluorescence and time resolved fluorescence spectroscopic characterization of oral tissues under UV excitation. The fluorescence emission spectra of oral tissues at 280 nm excitation were obtained. From the spectra, it was observed that the alteration in the biochemical and morphological changes present in tissues. Subsequently, the Full width at Half Maximum (FWHM) of every individual spectra of 20 normal and 40 malignant subjects were calculated. The student's t-test analysis reveals that the data were statistically significant (p = 0.001). The fluorescence excitation spectra at 350 nm emission of malignant tissues confirms the alteration in protein fluorescence with respect to normal counterpart. To quantify the observed spectral differences, the two ratio variables R1 = I275/I310 and R2 = I310/I328 were introduced in the excitation spectra. Among them, the Linear Discriminant Analysis (LDA) of R1 reveals better classification with 86.4 % specificity and 82.5 % sensitivity. The fluorescence decay kinetics of oral tissues was obtained at 350 nm emission and it was found that the decay kinetics was triple exponential. Then the ROC analysis of fractional amplitudes and component lifetime reveals that the average lifetime shows 77 % sensitivity and 70 % specificity with the cut off value 4.85 ns. Briefly, the average lifetime exhibits better statistical significance when compared to fractional amplitudes and component lifetimes.
authors.affiliation: Department of Medical Physics, Anna University, Chennai, 600 025, India.
authors.forename: Kanniyappan
authors.initials: K
authors.lastname: Udayakumar
authors.affiliation: Department of Medical Physics, Anna University, Chennai, 600 025, India.
authors.forename: Manoharan
authors.initials: M
authors.lastname: Yuvaraj
authors.affiliation: Department of Medical Physics, Anna University, Chennai, 600 025, India.
authors.forename: Fathi
authors.initials: F
authors.lastname: Awad
authors.affiliation: Department of Oral Medicine and Radiology, Meenakshi Ammal Dental College and Hospital, Chennai, 600 095, India.
authors.forename: Vadivel
authors.initials: V
authors.lastname: Jayanth
authors.affiliation: Department of Medical Physics, Anna University, Chennai, 600 025, India.
authors.forename: Prakasa Rao
authors.initials: PR
authors.lastname: Aruna
authors.affiliation: Department of Oral Medicine and Radiology, Meenakshi Ammal Dental College and Hospital, Chennai, 600 095, India.
authors.forename: Dornadula
authors.initials: D
authors.lastname: Koteeswaran
authors.affiliation: Government Arignar Anna Memorial Cancer Hospital and Regional Cancer Center, Karapettai, Kanchipuram, 631 501, India.
authors.forename: Munusamy Balu
authors.initials: MB
authors.lastname: David
authors.affiliation: Department of Medical Physics, Anna University, Chennai, 600 025, India. sganesan@annauniv.edu.
authors.forename: Singaravelu
authors.initials: S
authors.lastname: Ganesan
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D066298:In Vitro Techniques; D009055:Mouth / Q000737:chemistry*; D009062:Mouth Neoplasms / Q000473:pathology*; D013050:Spectrometry, Fluorescence / Q000379:methods*
keywords: Excited state kinetics; Fluorescence; Intrinsic fluorophores; Oral cancer; Tryptophan