Label-free chemical imaging flow cytometry by high-speed multicolor stimulated Raman scattering


Yuta Suzuki, Koya Kobayashi, Yoshifumi Wakisaka, Dinghuan Deng, Shunji Tanaka, Chun-Jung Huang, Cheng Lei, Hanqin Liu, Yasuhiro Fujiwaki, Sangwook Lee, Akihiro Isozaki, Yusuke Kasai, Takeshi Hayakawa, Shinya Sakuma, Fumihito Arai, Kenichi Koizumi, Hiroshi Tezuka, Mary Inaba, Kei Hiraki, Takuro Ito, Misa Hase, Satoshi Matsusaka, Kiyotaka Shiba, Kanako Suga, Masako Nishikawa, Masahiro Jona, Yutaka Yatomi, YalikunYaxiaer, Yo Tanaka, Takeaki Sugimura, Nao Nitta, Keisuke Goda, and Yasuyuki Ozeki*

Combining the strength of flow cytometry with fluorescence imaging and digital image analysis, imaging flow cytometry is a powerful tool in diverse fields including cancer biology, immunology, drug discovery, microbiology, and metabolic engineering. It enables measurements and statistical analyses of chemical, structural, and morphological phenotypes of numerous living cells to provide systematic insights into biological processes. However, its utility is constrained by its requirement of fluorescent labeling for phenotyping. Here we present label-free chemical imaging flow cytometry to overcome the issue. It builds on a pulse pair-resolved wavelength-switchable Stokes laser for the fastest-to-date multicolor stimulated Raman scattering (SRS) microscopy of fast-flowing cells on a 3D acoustic focusing microfluidic chip, enabling an unprecedented throughput of up to ∼140 cells/s. To show its broad utility, we use the SRS imaging flow cytometry with the aid of deep learning to study the metabolic heterogeneity of microalgal cells and perform marker-free cancer detection in blood.


Proceedings of the National Academy of Sciences of the United States of America(PNAS):