Single-Cell Metabolomics Using CE-NanoESI-Triple Quadrupole MS

Single-cell metabolomics is important for understanding cell-to-cell heterogeneity and to link cell neurochemistry to function. We are unraveling the differences between brain cells, including neurons, astrocytes, and more. 

We couple an Agilent 7100 CE system with the Agilent 6495C triple quadrupole LC/MS using 3D-printed parts as the CE/MS interface and use the system for single cell measurements. Different identified neurons were isolated from the central nervous system of Aplysia californica and individual neurons from the dorsal root ganglion of rodents. We performed sample preparation steps in vial inserts prepared from commercially-available 10 µL pipette tips; this enables us to work with and inject from a few microliter volumes. Other changes include a nanointerface and a mechanically-tapered capillary tip for optimized detectability.

Using the CE-MS system, metabolites in individual cells were characterized using multiple reaction monitoring mode with the QQQ-MS. The CE-nanoESI-QQQ MS system demonstrated detection limits in the attomole range for a range of amino acids and neurotransmitters. We characterize a range of different cells including Aplysia californica neurons, rodent neurons, and individual endocrine cells. The combination of nanovial CE-nanoESI-QQQ MS with the 3D-printed interface, auto sampler, and fast MS2 scanning enables high-throughput, high-sensitivity, and robust metabolite analysis of single cells.

Presenter: Jonathan V. Sweedler (James R. Eiszner Family Endowed Chair in Chemistry, Department of Chemistry, University of Illinois Urbana Champaign)

Jonathan Sweedler is the James R. Eiszner Family Endowed Professor of Chemistry, Acting Head of the Department of Chemistry, and affiliated with the Institute of Genomic Biology and the Beckman Institute for Advanced Science and Technology at the University of Illinois Urbana-Champaign. His research interests focus on developing new approaches for assaying small volume samples, including lipidomics, metabolomics and peptidomics using mass spectrometry. He uses these tools to characterize small molecules and peptides in a range of animal models across metazoan life and in samples as small as individual cells and cellular domains. Sweedler has published more than 500 manuscripts and presented 600 invited lectures. He has received numerous awards including the Instrumentation Award from the Analytical Division of the ACS, the Donald F. Hunt Distinguished Contribution in Proteomics Award from US HUPO and the ACS Award in Analytical Chemistry. He is a fellow of both the American Association for the Advancement of Science and the American Chemical Society. He is the Editor-in-Chief for Analytical Chemistry.