Nanomanipulation-coupled nanospray mass spectrometry as an approach for single cell analysis

Abstract

Electrospray mass spectrometry is now a widely used technique for observing cell content of various biological tissues. However, electrospray techniques (liquid chromatography and direct infusion) often involve lysing a group of cells and extracting the biomolecules of interest, rather than a sensitive, individual cell method to observe local chemistry. Presented here is an approach of combining a nanomanipulator workstation with nanospray mass spectrometry, which allows for extraction of a single cell, followed by rapid mass analysis that can provide a detailed metabolic profile. Triacylglycerol content was profiled with this tool coupled to mass spectrometry to investigate heterogeneity between healthy and tumorous tissues as well as lipid droplet containing adipocytes in vitro as proof of concept. This selective approach provides cellular resolution and complements existing bioanalytical techniques with minimal invasion to samples. In addition, the coupling of nanomanipulation and mass spectrometry holds the potential to be used in a great number of applications for individual organelles, diseased tissues, and in vitro cell cultures for observing heterogeneity even amongst cells and organelles of the same tissue.

Nanomanipulation-Coupled Matrix-Assisted Laser Desorption/ Ionization-Direct Organelle Mass Spectrometry: A Technique for the Detailed Analysis of Single Organelles

“…It should be noted, to explain the slight disparity in mass range, that the MALDI-DOMS spectra are adducted with sodium and the NSI-DOMS spectra are adducted with ammonium. The differences in the composition of TAG molecular species as shown in Figure 5c are illustrative to the heterogeneity of individual organelles and complementary to previous work [5,14]. This 5%-10% difference in composition is in stark contrast to the~1% RSD in the reproducibility of the standard (Figure 2).…”

“…This discovery led to the single cell and organelle investigation of other cell types with the nanomanipulator. In human breast tissue, cancer associated adipocytes (CAAs) and adjacent healthy adipocytes revealed distinct differences in heterogeneity of TAG molecular species composition from extractions using a two-tip method with the nanomanipulator using NSI [14]. Vastly different lipid profiles were also obtained dependent on lipid droplet size from whole cell digestions of differentiated human adipocytes using NSI, which validated the workstation as a valuable tool for in vitro cell cultures [18].…”

“…We have developed a nanomanipulation workstation capable of collecting trace particles [10][11][12][13], single cells, and subcellular organelles [5,14,15]. The workstation can be equipped with up to four piezoelectric nanopositioners capable of simultaneously utilizing different end effectors, including microgrippers, nanospray emitters, and microelectrodes that perform low impedance electrical characterizations.…”

Analysis of trace amounts of adulterants found in powders/supplements utilizing Raman spectroscopy coupled to direct analyte-probed nanoextraction-nanospray ionization-mass spectrometry

“…DAPNe-NSI-MS has been established as an extractive ambient ionization technique for: (1) drug residues from latent fingerprints, 37 (2) extraction of trace analytes for fiber analysis, 38 (3) forensic analysis of illicit drugs from electrostatic lifts, 39 (4) document and ink analysis, 40 and (5) biological cancer single cell/single organelle analysis. 41,42 This series of analytical techniques serves as a rapid screening method for a specific contaminant via Raman spectroscopy with positive identification providing localization for precise extraction via the DAPNe-NSI-MS method. The combination of these techniques could be quite accommodating in a situation in which the sample is limited.…”

Investigation of falsified documents via direct analyte-probed nanoextraction coupled to nanospray mass spectrometry, fluorescence microscopy, and Raman spectroscopy

“…12 DAPNe uses a device comprised of a nanomanipulator mounted on the stage of a high-powered microscope. 16 The advantage of DAPNe-NSI-MS for the analyses of ink and document examination is that it keeps the document in its pristine form. 16 The advantage of DAPNe-NSI-MS for the analyses of ink and document examination is that it keeps the document in its pristine form.…”