Single Cell CE-ESI MS Service
Single cell capillary electrophoresis-electrospray ionization mass spectrometer (CE-ESI MS) is a data acquisition method in single cell metabolomics workflow.
Principles of CE-ESI MS
CE-ESI MS is a soft ionization technique that converts ions in solution into gas-phase ions for MS analysis. The electrospray process can be described as follows.
- The sample solution is sprayed into mist-like charged droplets under the action of the electric field and the auxiliary airflow;
- The volatile solution gradually evaporates at high temperatures, and the charge density on the droplet's surface increases with the radius's decrease.
- Then, droplets undergo a Coulomb explosion at the Rayleigh limit, producing smaller charged droplets.
The above process is repeated continuously, and finally, the ionization of the sample is achieved. Since this process has no direct external energy acting on the molecule, it has less damage to the molecular structure and is a typical "soft ionization" method.
Fig.1 Diagram of CE-ESI MS. (Wikipedia)
Advantages of CE-ESI MS
- CE-ESI MS can provide a relatively simple way to transfer non-volatile solution-phase ions into the gas phase so that mass spectrometers can give a sensitive direct detection.
- In CE-ESI MS, high molecular weight molecules usually have multiple charges. Therefore, the distribution of charge states can quantify molecular weight and provide accurate molecular mass and structural information simultaneously.
- Timesaving.
- Various ionization modes.
- CE-ESI MS can be integrated with chromatography for complex system analysis
Single Cell Metabolomics Workflow
A typical workflow of single cell metabolomics starts with sample preparation to isolate a single cell or its cell content. Standard sample preparation methods include fluorescence-activated cell sorting (FACS), microfluidics arrays, and direct visualization and penetration/extraction via atomic force microscopy (AFM) probe. For whole-cell samples, sonication is reported to increase detection sensitivity.
- Sample preparation. A typical workflow of single cell metabolomics starts with sample preparation to isolate a single cell or its cell content.
- Immediately after isolating a single cell, the cellular metabolism should be quenched using liquid nitrogen or methanol to denature enzymes and prevent further metabolic conversion.
- Data acquisition, usually by MALDI-MS (Matrix-Assisted Laser Desorption/Ionization MS), ESI-MS, or SIMS (Secondary Ion MS)
Fig.2 Single cell metabolomics workflow. (Guo, 2021)
Creative Biolabs offer single-cell CE-ESI MS service to better understand metabolic responses in multiple cell types. If you have any requirements, please feel free to contact us for further communication about your project.
Reference
- Guo, S.H.; et al. The limitless applications of single-cell metabolomics. Current Opinion in Biotechnology. 2021, 71: 115-122.
