Preparation of single cells for imaging/profiling mass spectrometry

Abstract

Characterizing chemical changes within individual cells is important for determining fundamental mechanisms of biological processes that will lead to new biological insights and improved disease understanding. Analyzing biological systems with imaging and profiling mass spectrometry (MS) has gained popularity in recent years as a method for creating chemical maps of biological samples. To obtain mass spectra that provide relevant molecular information about individual cells, samples must be prepared so that salts and other cell culture components are removed from the cell surface and that the cell contents are rendered accessible to the desorption beam. We have designed a cellular preparation protocol for imaging/profiling MS that removes the majority of the interfering species derived from the cellular growth medium, preserves the basic morphology of the cells, and allows chemical profiling of the diffusible elements of the cytosol. Using this method, we are able to reproducibly analyze cells from three diverse cell types: MCF7 human breast cancer cells, Madin-Darby canine kidney (MDCK) cells, and NIH/3T3 mouse fibroblasts. This preparation technique makes possible routine imaging/profiling MS analysis of individual cultured cells, allowing for understanding of molecular processes within individual cells.

Liquid Chromatography-Mass Spectrometry Metabolic and Lipidomic Sample Preparation Workflow for Suspension-Cultured Mammalian Cells using Jurkat T lymphocyte Cells

“…Standard procedures for cell washing from mammalian cell culture media are vital because culture medium is often rich with amino acids and anions (e.g., Cl - , SO 4 2- , PO 4 3- ) that can mask low intracellular concentrations within cells [2,6,24,25]. Cell rinsing solutions for mass spectrometric analysis of suspension-cultured mammalian cells (Table 1) are inconsistent in the literature and have not been optimized for electrospray ionization [1,2,24,25].…”

Assessment of different sample preparation routes for mass spectrometric monitoring and imaging of lipids in bone cells via ToF-SIMS

“…14 However, it is not routinely used due to the technically challenging procedure, 17 high failure rates 28 and also because it lacks reproducibility. 29 Instead systematic investigations, especially those with a focus on lipids, still rely on other methods like glutaraldehyde fixation 30,31 or gelatin embedding.…”

“…28 The rinsing solution was used to remove excess salts from cell culture. For rinsing, the silicon wafer covered with cells was dipped into the solution followed by gently moving it forwards and backwards in the solution for about 30 s. C. Prior to analysis, the wafers were simply air dried.…”

ToF-SIMS of tissues: “Lessons learned” from mice and women

“…[12][13][14][15][16] Studies have been carried out in a variety of areas including the analysis of cancer cells, [17][18][19] cancer tissues, 20,21 muscular dystrophy, 22,23 and drug permeation into skin. 24 Several groups have discussed sample preparation methods for cells [25][26][27][28] and tissues. 14,29 However, the use of ToF-SIMS is still currently in early stages of development for answering biologically related questions.…”