Study On Fluorescence Spectrum Of White Blood Cells And Leukemia Cells

Leukemia is a hematopoietic malignancy which is harmful for human health, and the incidence and mortality of leukemia keep rising in recent years. In 2005, malignant neoplasm, in which leukemia accounts for 2.9%, became the topmost cause of population death in Chinese urban cities and accounted for almost one-third of the total deaths. The traditional methods used to diagnosis leukemia are blood tests, bone marrow tests(aspiration and biopsy), cytogenetic examination etc. Fluorescence spectroscopy is a non-invasive and hypersensitive spectral detection technology which based on the principle that the fluorescence spectrum of different molecule are different under excitation, and the different material molecules can be distinguished by related detection method.Objective:To realize the distinction of WBC and leukemia cell through their fluorescence spectrum and exogenous fluorescence spectrum, under the help of QuantaMaster, a steady state fluorescence measurement system. To lay the theoretical basis for leukemia diagnosis based on peripheral blood fluorescence spectrum, and to promote the application of fluorescence spectroscopy in leukemia diagnosis.Method:Autofluorescence spectrum of WBC and leukemia cell excitated at 370 nm、400 nm or 440 nm, fluorescence spectrum of leukemia cell incubated in ALA (ML,0.125mg/ml,0.25 mg/ml,0.5 mg/ml,1 mg/ml,2 mg/ml) or PSD-007 (0ug/ml,6.25ug/ml,12.5ug/ml,25ug/ml,50ug/ml, 100ug/ml) for 2 hours and excitated at 405 nm are detected and analyzed with characteristic peak integral or spectral normalization. Finally, relative peak intensity ratio and spectral subtraction methods are used to analysis the differences between WBC’s and leukemia cell’s autofluorescence spectrum excited at 370 nm,400 nm or 440 nm, and fluorescence spectrum incubated in ALA.Result:The position of P628 excited at excitation light of different wavelength didn’t red-shift or blue-shift, but the peak values were different. The beginning position and ending position of P636 (P626) in fluorescence emission spectrum of leukemia cells based on ALA(PSD-007) under different concentrations remained the same, but the peak values were different. I628/I515 of WBC’s autofluorescence spectrum excited at 400nm is about 2.9 times that of leukemia cell’s, and peak area percentage of the subtractive spectrum is about 91.4% at P628, I628/I515 of WBC’s (based on AlA) excited at 400nm is about 8.6 times that of leukemia cell’s (based on AlA), and peak area percentage of the subtractive spectrum is about 96.5% at P628.Conclusion:Excitation wavelength and photosensitizer concentration had no effect on the fluorescence peak position and only affected the fluorescence intensity; under the analysis of characteristic peak integral and spectrum subtraction, both autofluorescence characteristics and exogenous fluorescent characteristics had a significantly different between WBC and leukemia cell.