Pneumatically Assisted Nano-DESI Probe for Metabolomics

A group of scientists from Uppsala University and the Karolinska Institute in Sweden analyzed the metabolomics of individual cells using a pneumatically assisted (PA) nanospray desorption electrospray ionization (nano-DESI) probe of their own creation. Their work was published in the Journal of the American Society of Mass Spectrometry (1).

Cell Cross Section | Image Credit: © alswart - stock.adobe.com

Cellular heterogeneity is necessary to mitigate stress and improve a biological system’s resilience; however, to achieve this, scientists must be able to chemically analyze individual cells. One means of studying single-cell processes is metabolomics, which can analyze changes in seconds to minutes. This process can be challenging, partly due to rapid metabolite turnover rates, high complexity of metabolomes, and wide concentration ranges within a cell volume.

For this research, the scientists used a pneumatically assisted (PA) nanospray desorption electrospray ionization (nano-DESI), with the nano-DESI system that was previously used by the scientists for cheek cell metabolomics. DESI is a system that uses an electrospray source of highly charged aqueous spray droplets to desorb and ionize analyte molecules from a sample’s surface. This system allows a sample to be analyzed in its native state (2). The combination was also combined with tapered capillaries to show cellular imaging of IMR-90 cells and global metabolomics of individual INS-1 cells, while also showing a throughput of three cells per minute. In total, the scientists showed metabolomics optimization and exposure conditions for 479 unique INS-1 cells.

Using the PA nano-DESI probe, scientists were able to sample six lines from a large senescent IMR-90 cell, which allowed for a comprehensive assessment of metabolite distribution across the cell area. Different lipid species were evenly distributed over the large cell, which contrasts with other amino acids, which typically show heterogeneous distributions over a cell area.

Metabolome alterations in INS-1 cells were monitored in low and high glucose concentrations, using 93 and 97 cells respectively. Additionally, using a touch-down mode with an analysis of 3 cells per minute, there was higher throughput for metabolomics for cells spotted and analyzed in an array.

References

(1) Marques, C.; Friedrich, F.; Liu, L.; Castoldi, F.; Pietrocola, F.; Lanekoff, I. Global and Spatial Metabolomics of Individual Cells Using a Tapered Pneumatically Assisted nano-DESI Probe.J. Am. Soc. Mass Spectrom. 2023, 34 (11), 2518–2524. DOI: https://doi.org/10.1021/jasms.3c00239

(2) Desorption Electrospray Ionization. Elsevier B.V. 2017. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/desorption-electrospray-ionization (accessed 2023-11-21)