Highly Efficient Microscale Purification of Glycerophospholipids by Microfluidic Cell Lysis and Lipid Extraction for Lipidomics Profiling

Abstract

This article presents a novel method for small-scale lipidomics of bacterial cells by integrating extraction of glycerophospholipids on microchip with a nanoelectrospray ionization quadrupole time-of-flight tandem mass spectrometer (nanoESI-Q-TOF MS/MS). The standard starting point for typical macroscale lipid analysis is a multiphase liquid-liquid extraction. Working with small populations of cells (1 to about 1000) requires a scaled down process in order to minimize dilution and facilitate the interface with microscale separation methods for sample cleanup and introduction to mass spectrometry. We have developed a microfluidic system that allows for lysis of bacterial cells, capture of lipids, and elution of captured lipids from a solid phase for microscale purification of lipids. The best on-chip extraction efficiency for glycerophospholipids was as high as 83.3% by integrating silica beads as the packing material with methanol as the eluent. Ten successive measurements were evaluated indicating that the microchip packed with fresh silica beads is capable of being reused for four times without any loss in lipid extraction process. The initial screening based on high-resolution tandem mass spectrometry data along with discovery profiling approach revealed the presence of 173 identified phospholipid species from microfluidic cell extracts. This work demonstrates the potential of incorporating microchip-based lipid extraction into cellular lipidomics research.

Simultaneous extraction and rapid visualization of peptidomic and lipidomic body fluids fingerprints using mesoporous aluminosilicate and MALDI‐TOF MS

“…It has been found that the amount of protein adsorbed on the aluminum‐substituted mesoporous adsorbents is higher as compared to their pure silica analogues . Additionally, normal‐phase silica sorbents have shown great selectivity toward LP extraction . Therefore, the aluminum‐substituted MPS was our material of choice.…”

“…It should be considered that MALDI‐TOF MS allows very rapid analysis with an output of MS data and a resolution higher than SELDI‐TOF MS (resolution that enables a more accurate analysis of peak area changes in comparative studies). Moreover, MALDI‐TOF MS is a “user friendly” technology, available to several analytical laboratories as compared to quadrupole‐TOF MS, hybrid linear ion trap FT‐ICR MS, and high‐resolution LIT‐Orbitrap MS, which have been also proposed for lipidomic studies . Therefore, these preliminary findings strongly suggest the potential of this approach to reduce the gap between high‐throughput proteomics and clinic‐enabling studies with large cohorts of patients.…”

Analytical challenges of shotgun lipidomics at different resolution of measurements

“…Microfluidic devices may have the potential to enhance micro level lipid analysis [77]. In this study by Sun et al, the authors integrated solid-phase microextraction materials into microfluidic tubing.…”

Mass Spectrometry Methodology in Lipid Analysis

“…ESI is also easily hyphenated to other separation technologies, like capillary electrophoresis [ 70 ] and a microfluidic system [ 71 ]. Because the microfluidic technique can integrate different functions on one single chip, such as the lysis of cells, the capture of lipids and the elution of captured lipids from a solid phase for the microscale purification of lipids, it may present a highly efficient technique for comprehensive lipidomics research.…”

“…For nonpolar lipids, which cannot form charged droplets in solutions, APCI and APPI were more suitable for their analysis [ 69 , 70 ]. Moreover APCI and APPI are less susceptible to the effect of ionization suppression and salt buffer effects than ESI [ 71 , 72 , 73 , 74 ]. In 2013, Tian et al .…”