| 1. |
Takayuki Kawai, Ultra-sensitive Bioanalysis by Dual-Stacking Capillary Electrophoresis, 19th Asia-Pacific International Symposium on Microscale Separations and Analysis 2023 (APCE 2023), 2023.10, Capillary electrophoresis (CE) is an efficient separation technique for biomolecules, however, concentration sensitivity is usually very low because the sample injection volume is quite limited (~nL). To address this issue, online sample preconcentration (OSP) methods have been developed. However, OSP methods often provide only 100-fold or poorer sensitivity improvement in exchange for the loss of resolution, requiring cumbersome optimization for each type of sample. Thus, it is rare to use OSP methods for routine CE bioanalysis. Here, we developed two types of novel OPS methods, large-volume dual preconcentration by isotachophoresis and stacking (LDIS) and large-volume dual preconcentration by micelle collapse and sweeping (LDMS).
LDIS was designed for the analysis of charged molecules, which was firstly applied to N-linked glycans. Owing to the dual stacking mechanism, 2,000-fold sensitivity improvement was achieved without losing the resolution at all. Finally, the around 40 glycans were successfully profiled from quite limited number of cells (~100). LDIS was also applied to metabolome analysis. Single HeLa cells were collected by micro-manipulation and analysed by LDIS-CE-mass spectrometry (MS). Forty metabolites were profiled from a single HeLa cell and limit of detection of 450 fM (10–15 M, S/N = 3) was achieved.
LDMS was designed for uncharged hydrophobic compounds like drugs. DXd, an efficient anti-cancer payload, was extracted from a tissue slice and analysed by LDMS-CE-MS using sodium dodecyl sulfate micelle as pseudo-stationary phase. DXd was trapped by the micelle and eluted by acetonitrile-induced micelle collapse, resulting in 1,000-fold preconcentration and limit of quantification of 420 fM (S/N = 10). Since the hydrophilic metabolites were not trapped by the micelle, DXd was separated from the cellular contaminants, and attomole-level of DXd was successfully quantified from tissue microsections,. |
| 2. |
Takayuki Kawai, Development of Ultra-sensitive Capillary Electrophoresis toward Trace N-glycan Profiling, Asian Glyco Webinar, 2022.04. |
| 3. |
Takayuki Kawai, Development of Ultra-sensitive Capillary Electrophoresis and Application to in vitro/vivo Trace Bioanalysis, Pittcon 2021, 2021.03. |
| 4. |
Takayuki Kawai, Quantitative Single Cell Metabolomics by CE-MS, 17th Asia-Pacific International Symposium on Microscale Separations and Analysis (APCE2017), 2017.11. |
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Takayuki Kawai, Ultra-sensitive Capillary Electrophoresis for Single Cell Omics Research, Pittcon 2017, 2017.03. |
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Takayuki Kawai, Ultra-sensitive CE-LIF/MS System for Single Cell Omics Research, 16th Asia-Pacific International Symposium on Microscale Separations and Analysis (APCE2016), 2016.11. |
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Takayuki Kawai, High performance CE-MS system for single cell analysis, 32nd International Symposium on Microscale Separations and Bioanalysis (MSB 2016), 2016.04. |
| 8. |
キャピラリー電気泳動を用いた高感度一細胞分析法の開発. |
| 9. |
Takayuki Kawai, Ultra-sensitive capillary electrophoresis for single cell analysis, International Conference and Expo on Separation Techniques 2015, 2015.08. |
| 10. |
Takayuki Kawai, Sensitive and Flexible Single-Cell Analysis via Capillary Electrophoresis Coupled with an Online Sample Preconcentration Method, 1st Caparica Christmas Conference on Sample Treatment (Sample Treatment 2014), 2014.12. |
| 11. |
Takayuki Kawai, Amit Patel, Stanislav S Rubakhin, Jonathan V Sweedler, Analysis of D-Glutamate in a Single Cell via Capillary Electrophoresis Coupled with an Online Sample Preconcentration Method, The 2nd International Conference of D-Amino Acid Research (IDAR 2014), 2014.09. |
| 12. |
Takayuki Kawai, Stanislav S. Rubakhin, Jonathan V. Sweedler, Analysis of Enantiomeric Amino Acids in Biological Samples via Capillary Electrophoresis Coupled with Mass Spectrometry, AS-MS 2014, 2014.06. |
| 13. |
Takayuki Kawai, Simple and High-Performance On-chip Bioanalysis, EMN Summer Meeting 2014, 2014.06. |
| 14. |
Takayuki Kawai, Nobutoshi Ota, Jonathan V. Sweedler, Analysis of Enantiomeric Amino Acids in Biological Samples via Capillary Electrophoresis Coupled with Laser-induced Fluorescence and Mass Spectrometry, Pittcon 2014, 2014.03. |
| 15. |
Takayuki Kawai, Masumi Ueda, Kenji Sueyoshi, Fumihiko Kitagawa, Koji Otsuka, Toward 10,000-fold Sensitivity Improvement in Capillary Electrophoresis of Oligosaccharide, 11th Asia-Pacific International Symposium on Microscale Separations and Analysis (APCE 2011), 2011.11. |
| 16. |
Takayuki Kawai, Masumi Ueda, Kenji Sueyoshi, Fumihiko Kitagawa, Koji Otsuka, Toward 10,000-fold Sample Preconcentration Efficiency for Oligosaccharide Analysis in Capillary Electrophoresis, 37th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2011 Dalian), 2011.10. |
| 17. |
Takayuki Kawai, Jun Ito, Kenji Sueyoshi, Fumihiko Kitagawa, Koji Otsuka, Highly Sensitive Chiral Analysis by Capillary Electrophoresis Using Large-volume Sample Stacking with Electroosmotic Flow Pump, IUPAC International Congress on Analytical Sciences 2011 (ICAS 2011), 2011.05. |
| 18. |
Takayuki Kawai, Jun Ito, Kenji Sueyoshi, Fumihiko Kitagawa, Koji Otsuka, Highly Sensitive Chiral Analysis in Capillary Electrophoresis Using Large-volume Sample Stacking with Electroosmotic Flow Pump, 26th International Symposium on Microscale Bioseparations (MSB 2011), 2011.05. |
| 19. |
Takayuki Kawai, Kenji Sueyoshi, Fumihiko Kitagawa, Koji Otsuka, Microchip Electrophoresis of Oligosaccharides with Large-volume Sample Stacking with Electroosmotic Flow Pump in Single Channel, 2010 International Chemical Congress of Pacific Basin Societies (PACIFICHEM 2010), 2010.12. |
