Optical tweezers assisted analyzing and sorting of tumor cells tagged with fluorescence nanospheres in a microfluidic chip

Due to the vital role of studying a single tumor cell, it is meaningful to establish a compatible means to realize the analysis and sorting tasks. Despite plentiful strategies have been developed, there is still a challenge to develop a fully integrated approach to be directly used in biological samples. As such, we present here a special fluorescence activated cell sorting platform assisted by optical tweezers (FACS-OT) in a microfluidic chip. To begin with, according to the significant differences in the protein expression level of cell surface, two kinds of cells are severally immunotagged with quantum dots embedded two-color fluorescent nanospheres. And then, by the home-built setup, different cells are stably and accurately detected one by one for single-cell level with two-color fluorescence resolved in the microfluidic chip. Finally, the home-built apparatus of FACS-OT is successfully used for highly precise deflection of targeted cells (deflection ratio of 95.7%) under the radiation of optical force. In addition, the results of simulation agree with our experiment, which offer a stable platform for further application. In line with above efforts, we establish a special platform by automatic analysis and deflection of single cell, offering a special strategy for studying heterogeneity in single cell. • Optical tweezer (OT) is a special tool for sorting cells in the microfluidic chip. • Quantum dots embedded two-color fluorescent nanospheres are used for labeling different cells. • Highly precise deflection of targeted cells is obtained by employing the home-built apparatus of FACS-OT.