Qualitative and Quantitative Analysis of Tumor Cell Metabolism via Stable Isotope Labeling Assisted Microfluidic Chip Electrospray Ionization Mass Spectrometry

Abstract

In this work, a stable isotope labeling assisted microfluidic chip electrospray ionization mass spectrometry (SIL-chip-ESI-MS) platform for qualitative and quantitative analysis of cell metabolism was developed. Microfluidic cell culture, drug-induced cell apoptosis analysis, and cell metabolism measurements were performed simultaneously on the specifically designed device. MCF-7 cells were cultivated in vitro and exposed in anticancer agent (genistein and genistein-d(2)) for cell-based drug assay. A dual-isotopic labeling was presented for effective qualitative analysis of multiplex metabolites. Interestingly, three coeluting pairs of isotopomers appeared with an m/z difference of two. Despite complex biological matrixes, they can be easily recognized and identified by chip-ESI-MS/MS, which significantly facilitates candidate biomarker discovery. The quantitative performance of this system was evaluated using genistein as a model drug by means of stable isotope dilution analysis. The linear equation obtained is y = 0.06x - 3.38 × 10(-3) (R(2) = 0.995) at the dynamic range from 0.5 to 40 μM. The detection limit is 0.2 μM. The method shows an excellent stability of 2.2% relative standard deviation (RSD) and a good repeatability of 5.5% RSD. Our results have successfully demonstrated the capability of selective and quantitative analysis of cell-based drug absorption and metabolites with high stability, sensitivity, and repeatability on the chip-ESI-MS system. Consequently, the present device shows promise as a high-throughput, low-cost, and online platform for cell metabolism studies and drug screening processes.

Engineering Cell‐Compatible Paper Chips for Cell Culturing, Drug Screening, and Mass Spectrometric Sensing

“…[ 27,28 ] Since the cell-compatible paper chips allows for adherent cell culture, directly monitoring intracellular drugs is thus possibly performed by label-free sensing via paper spray mass spectrometry. First, we culture the HepG2 cells on the paper chips, and incubate them with 100 µL cyclophosphamide (CPA, 5.0 µmol mL -1 ) after one day's culture for cell adhesion.…”

Microfluidic Platforms for Single-Cell Protein Analysis

“…15,69 Fluorescence-based technologies provide highthroughput and high-information content analysis but often are limited by the available genetic and chemical probes; MS can be highly sensitive and requires neither prelabeling nor purification of proteins. However, the lack of an effective interface between sample preparation and the detection is an obstacle for MS to be widely applied in single-cell protein analysis via microfluidics.…”

“…66 The development of PDMS-glass hybrid chips and the detection of amino acids through chemiluminescence also improved the usability of microfluidic CE. 81,82 To address the lack of an effective interface between miniaturized sample preparation and the mass spectrometer, 70 Mellors et al 15 reported continuous on-chip lysis of erythrocytes with real-time electrophoretic separation and electrospray ionization MS. More recently, Chen et al 69 demonstrated a isotope labeling-assisted microfluidic chip electrospray ionization MS platform for quantitative and qualitative analysis of multiplex metabolites in MCF-7 cells (Fig. 4B).…”

Microfluidics for cell-based high throughput screening platforms—A review

“…Chen et al [48] reported a platform based on stable isotope labeling carried out in a microfluidic chip with electrospray ionization mass spectrometry (SIL-chip ESI-MS) for qualitative and quantitative analysis of the metabolism of cells treated by drugs. This platform, shown in Fig.…”