Flow cytometer based on triggered supercontinuum laser illumination

Multiple wavelength operation in a flow cytometer is an exciting way for cell analysis based on both fluorescence and optical scattering processing. For example, this multiparametric technique is currently used to differentiate blood cells subpopulations. The choice of excitation wavelengths matching fluorochrome spectra (it is currently the opposite) and the use of a broader range of fluorochromes can be made by taking advantage of a filtered supercontinuum white light source. In this study, we first wished to validate the use of a specific triggered supercontinuum laser in a flow cytometer based on white light scattering and electric sizing on human blood cells. Subsequently, to show the various advantages of this attractive system, using scattering effect, electrical detections, and fluorescence analysis, we realized cells sorting based on DNA/RNA stained by thiazole orange. Discrimination of white blood cells is efficiently demonstrated by using a triggered supercontinuum-based flow cytometer operating in a "one cell-one shot" configuration. The discriminated leukocyte populations are monocytes, lymphocytes, granulocytes, immature granulocytes, and cells having a high RNA content (monoblasts, lymphoblasts, and plasma cells). To the best of our knowledge, these results constitute the first practical demonstration of flow cytometry based on triggered supercontinuum illumination. This study is the starting point of a series of new experiments fully exploiting the spectral features of such a laser source. For example, the large flexibility in the choice of the excitation wavelength allows to use a larger number of fluorochromes and to excite them more efficiently. Moreover, this work opens up new research directions in the biophotonics field, such as the combination of coherent Raman spectroscopy and flow cytometry techniques.