Microfluidic cytometry has led to great progress in the field of single cell analysis. Here a light scattering microfluidic cytometer with dual-channel three-dimensional (3D) hydrodynamic focusing is developed, which potentially enables single cell or particle measurements with high-throughput. The light sheet illumination is introduced to provide a uniform excitation. Two dimensional (2D) light scattering patterns of label-free single cells or particles are imaged by a CMOS sensor via an objective lens (10x). The focusing effect of our dual-channel 3D hydrodynamic focusing unit is visualized. Simultaneous measurements of standard beads with different concentrations and sizes are performed. Our results demonstrate that the light scattering microfluidic cytometer with dual-channel 3D hydrodynamic focusing is promising for parallel, label free analysis of various cells with an enhanced throughput.
The detection of senescent cells becomes increasing important for tumor therapy and drug screening. Here a light sheet microfluidic cytometer with a disposable hydrodynamic focusing unit is developed for two dimensional (2D) light scattering measurements of single cells. The mixed polystyrene microspheres of 3.87 and 2.0 μm in diameter are successfully differentiated by our 2D light scattering microfluidic cytometer. The application of the 2D light scattering microfluidic cytometry for the label-free analysis of senescent cells without any labeling or staining is demonstrated by measurements of H<sub>2</sub>O<sub>2</sub>-treated U87 cells. Our light sheet-based 2D light scattering microfluidic cytometer is easy to assemble with a disposable hydrodynamic unit, which may find wild applications in clinics for label-free cell classification.
Two-dimensional (2D) light scattering cytometry has been demonstrated as an effective label-free technology for cell analysis. Here we develop the light-sheet illumination in 2D light scattering static cytometry. In our cytometer, a cylindrical lens is used to form the light-sheet for better excitation of the static cells under an inverted microscope. The thickness of the light-sheet measured in fluorescent solution is about 13 μm. Two-dimensional light scattering patterns of standard microspheres and yeast cells are obtained by using a complementary metal oxide semiconductor (CMOS) detector via a low numerical aperture (NA 0.4) optical objective. The experimental patterns characterized with fringe structures agree well with Mie theory simulated ones. Our results suggest that the light-sheet illumination is an effective excitation method for 2D light scattering label-free cytometry.