2020 Volume 69 Issue 12 Pages 753-757
Recently, single-cell analysis methods, such as fluorescence-activated cell sorting and single-cell transcriptome analysis, have been employed in many biological studies in order to elucidate the characteristics of each cell. So far, genome, transcriptome, proteome, and metabolome analyses have been achieved on the single-cell scale. Single-cell metabolome analysis was usually carried out with mass spectrometry (MS); however, no standard metabolome method has been reported that has sensitivity, quantitation/qualification reliability, and analytical robustness. To address this issue, we focused on capillary electrophoresis (CE)-MS, which has great quantitative reliability, but poor sensitivity. In order to improve the sensitivity, an online sample preconcentration method, large-volume dual preconcentration by isotachophoresis and stacking (LDIS) was applied. Up to 750-fold sensitivity improvement was achieved in the analysis of 20 standard amino acids. A sensitive and robust sheathless ionization emitter that has a thin-walled conductive segment and a flat outlet end was also employed. As a result, an ultra-sensitive metabolome analysis with up to 800 fmol L−1 limit of detection was achieved. Finally, a single MCF-7 cell was analyzed by LDIS-CE-MS, where totally 42 metabolites were identified. This ultra-sensitive and robust metabolome analysis method is promising for next-generation single cell metabolome analysis.
