Traditional vs advanced methods for metabolomics analysis

Metabolomics is the study of small molecules or metabolites in biological systems. Metabolites are used as biomarkers for diseases detection or discovery of new therapeutic targets. Traditional metabolomics analysis is done using gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-mass spectrometry (LC-MS). In recent years, technological advancements made new methods available for metabolomics analysis, such as nuclear magnetic resonance (NMR) and matrix-assisted laser desorption/ionization (MALDI).

Traditional Methods

GC-MS and LC-MS are the most common methods used for metabolomics analysis. Both techniques involve separating the metabolites using chromatography, followed by detection using mass spectrometry.

GC-MS works by vaporizing the metabolites into a gas and separating them based on their physical and chemical properties. The resulting gas is then analysed using mass spectrometry. GC-MS is useful for volatile and thermally stable metabolites, such as amino acids and fatty acids.

In contrast, LC-MS separates the metabolites based on differences in their chemical and physical properties in a liquid. The resulting mixture is then analysed using mass spectrometry. LC-MS is useful for non-volatile and non-polar metabolites such as nucleotides and peptides.

Advanced Methods

Advanced metabolomics techniques such as NMR and MALDI have emerged in recent years.

NMR spectroscopy works by using a strong magnetic field to align the nuclei of metabolites. A radiofrequency pulse is used to excite these nuclei, causing them to emit a signal when they return to their original alignment. NMR is useful for identifying structural changes in metabolites, but it is limited to detecting only relatively high-concentration metabolites.

MALDI, on the other hand, is a technique that is used to ionize compounds on a sample surface using a laser pulse. The resulting ions are then analyzed using mass-specific detectors. MALDI is useful for the analysis of molecules such as proteins and peptides, which are more easily ionizable than other compounds using GC-MS and LC-MS.

Comparison

Both traditional and advanced methods have their advantages and disadvantages. Traditional methods, such as GC-MS and LC-MS, have high sensitivity, reproducibility, and are well-established methods. However, they require sample derivatization, which can introduce variability between samples. They are also limited in their ability to detect less abundant metabolites.

Advanced methods, such as NMR and MALDI, do not require sample derivatization and are capable of detecting metabolites that traditional methods cannot. NMR spectroscopy allows for the detection of structural changes in metabolites, while MALDI is useful for detecting large biomolecules. However, these techniques have lower sensitivity compared to traditional methods and do not cover as many metabolites.

Conclusion

Advancements in technology have brought new methods for metabolomics analysis. Both traditional and advanced methods have their strengths and weaknesses. Traditional methods offer high sensitivity and reproducibility but require sample derivatization. Advanced methods are capable of detecting metabolites that traditional methods cannot but lack sensitivity.

References

1. Fiehn O, Robertson D, Griffin J, et al. The metabolomics standards initiative (MSI). Metabolomics. 2007;3(3):175-178. doi:10.1007/s11306-007-0082-2
2. Ardini YD, Sukorini MW. Nuclear Magnetic Resonance (NMR) as a Promising Diet Selection Indicator: A Review. Iran J Public Health. 2019;48(1):10-17. Published 2019 Jan 1.
3. Walch A, Rauser S, Deininger SO, et al. MALDI imaging mass spectrometry for direct tissue analysis: a new frontier for molecular histology. Histochem Cell Biol. 2008;130(3):421-434. doi:10.1007/s00418-008-0467-9