UV-native fluorescence steady and excited state kinetics of salivary protein of normal subjects, oral premalignant and malignant conditions

A pilot study has been carried out to characterize human salivary protein to discriminate the normal subjects from patients with oral premalignant lesions and oral squamous cell carcinoma (OSCC) conditions, using the native fluorescence emission spectra at 280 nm excitation, the fluorescence excitation spectra for 350 nm emission and time resolved fluorescence decay kinetics of protein fluorescence in the saliva. A markeable difference in the spectral signatures between the saliva of normal subjects from oral premalignant lesion and OSCC conditions were observed in both fluorescence emission spectra at 280 nm excitation and the fluorescence excitation spectra at 350 nm emission maxima. The possible reasons for the altered spectral signature were may be due to the altered microenvironment of saliva and its constituents during the transformation of normal into oral premalignant lesion and OSCC conditions. Based on the observed spectral difference an attempt have been made to determine the statistical significance. The discriminant analysis for the fluorescence emission spectra at 280 nm excitation of saliva of normal subject and OSCC conditions provides 77.8% specificity and 86.6% sensitivity and the fluorescence excitation spectra of the same discriminates with 77.8% specificity and 86.8% sensitivity. The time resolved fluorescence decay kinetics were also confirmed the alteration in the spectral signature were due to the alteration in the microenvironment of saliva and its constituents.