The most commonly used method for single cell isolation is Fluorescence-Activated Cell Sorting (FACS) currently. However, it needs fluorescence labeling normally, and only obtains limited phenotypes, conducting hardly “in situ” identification. However, Raman microscopy is a non-invasive method to acquire thechemical fingerprint of the whole single-cell without the need of labeling, identifying rapidly single-cell genotypes, physiological states and metabolite changes, etc. Therefore, it is of great importance to functional identification and resource exploitation of uncultured microorganisms.

Dr. WANG Yun, Ms. JI Yuetong and their colleagues from the Single-Cell Center of Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences, developed a method to significantly increase the speed of Raman spectrum acquisition for a single microbial cell by optimizing the light-path and increasing laser power, etc. For the first time, the acquisition time of a single microbial cell Raman spectrum is reduced to millisecond level, laying a solid foundation for high throughput sorting based on Raman spectroscopy.

In addition, based on the principle of laser induced forward transfer (LIFT), Dr. WANG Yun and her team invented Raman-activated Cell Ejection (RACE), which can be used to isolate single cells with specific Raman phenotypes from complicated microbiota for further genomic identification. It provides a new sorting method for Raman-activated Cell Sorter (RACS). This research result has been published on Analytical Chemistry.

The research is co-led byProfessor HUANG Wei from the University of Sheffield and Professor XU Jian from the Single Cell Center of Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) and is published on Analytical Chemistry (2013) titled Raman activated cell ejection for isolation of single cells.

Figure A. Microscopic image before ejection; B. Microscopic image after ejection; C. Raman spectra of single cells; D. Genomic amplification products of single cells.

(Image by Single-Cell Center of QIBEBT)