High throughput solid phase microextraction: A new alternative for analysis of cellular lipidome?

Abstract

A new SPME method for untargeted lipidomic study of cell line cultures was proposed for the first time. In this study the feasibility to monitor changes in lipid profile after external stimuli was demonstrated and compared to the conventional Bligh & Dyer method. The human hepatocellular carcinoma (HCC) cell line was used as a model. The obtained results provided a list of up-regulated and down-regulated lipids through a comparison between control (non-stimulated) cells versus the group of cells treated with polyunsaturated fatty acid (20:5). Use of the SPME technique yielded a list of 77 lipid species whose concentrations were recognized to be significantly different between control and treated cells, from which 63 lipids were up-regulated in treated cells. In general, the list was comparable to the peer list obtained by the Bligh & Dyer method. However, more diversity of lipid classes and subclasses such as LPC, sphingomyelins, ceramides, and prenol lipids were observed with the application of the SPME method. Method precision for the SPME approach was within the acceptable analytical range (5-18% RSD) for all detected lipids, which was advantageous over solvent extraction applied. The evaluation of ionization efficiency indicated no matrix effect for the SPME technique, while Bligh & Dyer presented significant ionization suppression for low abundant species such as LysoPC, PG, ceramides, and sphingomyelins, and ionization enhancement for high abundant phospholipids such as PE.

Qualitative analysis of phospholipids and their oxidised derivatives – used techniques and examples of their applications related to lipidomic research and food analysis

“…Consequently, this can result in reduced sensitivity and inaccurate or irreproducible MS measurements [47]. The techniques of initial sample preparation for PL analysis include liquid-liquid extraction (LLE), protein precipitation (PPT) and, more recent, solvent saving direct immersion solid phase microextraction (DI-SPME), which has attracted considerable attention [33,48,49]. Some enrichment of lipid fraction in PLs is possible with the aid of solid phase extraction (SPE) procedures.…”

“…Samples derived from cell cultures must be first thoroughly washed from serum-borne lipids. Depending on the further procedure used, the cells can be homogenised [48] or more commonly the lipids are extracted from the cell pellet directly by the addition of cold solvents [65,67]. In turn, liquid samples, such as serum or plasma as well as foodstuffs, e.g.…”

“…The conventional sample preparation methods, LLE and combined liquid-liquid extraction and solid phase extraction (LLE-SPE) are based on manual lipid isolation. These methods are overly time consuming to be employed for routine analyses of many samples, which is commonly required in lipidomic studies [48]. Therefore, there has been recently a growing interest in direct immersion solid phase microextraction (DI-SPME) for the study of lipid compounds, including PLs.…”

“…DI-SPME technique is based on adsorption of analytes on the surface of thin glass or quartz fibre coated with a specific sorbent. Silica-based sorbents modified with C18 groups are often used for lipidomic applications [48,49,88]. When the analyte concentrations reach distribution equilibrium between the fibres surface and the sample matrix, the coated fibres are immersed in purified water to remove sample residues.…”

Determination of lipid mediators in breast cancer cells using lyophilization‒supercritical fluid extraction online coupled with supercritical fluid chromatography‒quadrupole tandem mass spectrometry

“…There have been some well‐established methods for the analysis of lipids from cell samples. The traditional extraction methods include LLE , SPE , and SPME , which usually consume a large volume of toxic organic solvents and need long extraction time. GC‒MS and LC‒MS are the two predominant quantification methods to determine lipid mediators in cells.…”