Interfacing CE with Mass Spectrometry
for Single Cell Measurements

Understanding brain function in healthy and diseased brains requires an understanding of the biochemistry occurring within the neurons and supporting cells making up the brain.  What is the cell to cell variation of the cellular metabolome in the nervous system?  For most metabolites, the answer is unknown.  Capillary electrophoresis (CE) with electrospray ionization mass spectrometry detection (ESI-MS) is a technique that has great potential for performing metabolomic profiling—CE provides high resolution separations of small charged molecules, and ESI-MS allows for the detection and characterization of eluting analytes. 

For metabolomic profiling to be successful, a robust system is required, so that run-to-run variations reflect real differences between samples, and not instabilities in instrument performance.  Our lab is working to develop a sensitive and robust CE-ESI-MS system suitable for metabolomics applications at the single cell level.  Using the system developed thus far, we detect many known signaling molecules including dopamine, serotonin, and acetylcholine in extracts of single identified neurons.  Future work involves characterizing the neurotransmitters in cells of well-known neuronal networks to aid in understanding the mechanisms of their function.

CE MS image

Above: The analysis of the metabolome of individual neurons using capillary electrophoresis ESI-MS. (A) Schematic of the CE-MS system with (B) an enlarged schematic of the interface between the CE capillary and the ESI source.  (C) An isolated Aplysia neuron, and (D) the resulting electropherogram with acetylcholine highlighted.  

Relevant Publications:
Lapainis, T., Rubakhin, S., Sweedler, J.V., Characterization of single neurons using capillary electrophoresis with electrospray ionization mass spectrometric detection, ASMS Conference on Mass Spectrometry and Allied Topics, Denver, CO, June 5, 2008 (poster).

Capillary Electrophoresis