Metabolites are the end products of gene and protein regulation, closest to the phenotype. Spatial metabolomics anchors the 'molecular inventory' of metabolomics back to tissue coordinates, answering questions such as 'in which region of the tissue is a certain metabolite high, in which region is it low, and does it coincide with the pathological boundary'. Compared with single-region homogenate detection, it preserves the heterogeneity of tissue microregions, and is key to understanding the tumor microenvironment, drug action mechanisms, and the meridian tropism of active components in traditional Chinese medicine.
Methodologically, spatial metabolomics is almost equivalent to 'mass spectrometry imaging with metabolites as the object': tissue section → imaging ion source ionization point by point → mass analysis → reconstruct metabolite spatial distribution map by m/z. Therefore the choice of ion source (resolution, whether matrix-free, ability to cover small molecules) directly determines the data quality of this field.
MALDI: mature and broad coverage, but matrix peaks interfere in the low-mass region and it is poorly suited to small-molecule drugs and metabolites. DESI: ambient matrix-free, suitable for metabolites/lipids, but with limited resolution and polarity coverage. SIMS: nanometer-scale, suitable for elements/small-molecule fragments, but hard ionization and difficult quantification. LDPI (Neo-Source): matrix-free, ambient, 2–3 μm, no matrix interference can detect m/z as low as 70, suitable for small-molecule low background and single-cell/subcellular scale.
| Ion source | Matrix | Resolution | Low background for small molecules | Compatibility notes |
|---|---|---|---|---|
| MALDI | Required | Tens of μm | Affected by matrix | Mature, broad coverage |
| DESI | Not required | Tens–hundreds of μm | Good | Ambient, matrix-free |
| SIMS | Not required | Nanometer-scale | Good (fragments) | Hard ionization, hard to quantify |
| LDPI (Neo-Source) | Not required | 2–3 μm | Excellent (m/z≥70) | Matrix-free, ambient, compatible with mainstream instruments |
Tumor research: mapping the metabolic heterogeneity of tumor and paracancerous tissues, searching for metabolic biomarkers that distinguish boundaries and subtypes. Drug development: tracking the spatial distribution of candidate drugs and their metabolites within organs and tumors, supporting tissue-level pharmacokinetic analysis. Traditional Chinese medicine research: micro-localization of Chinese medicinal materials and formulas, presenting the meridian tropism and accumulation of active components in tissue. In addition, forensic evidence, plant metabolism, microbial colony metabolism, and environmental microplastic distribution are also rapidly expanding.
It must be emphasized that the interpretation of metabolite spatial distribution cannot be separated from biological context: the same m/z may correspond to isomers, and molecular annotation needs to be combined with standards, tandem mass spectrometry, or databases. Therefore spatial metabolomics is both a discovery tool and relies on rigorous annotation workflows.
When resolution enters the μm and even sub-micron range, spatial metabolomics can probe at the single-cell or even subcellular scale: 'is the distribution of the same molecule different in normal versus diseased cells', 'metabolic fingerprint differences among different cells in the microenvironment'. Neo-Source MSI LDPI (2–3 μm, optimizable to 4 μm) has already presented single-cell/subcellular-scale metabolite distributions in studies of melanoma skin tissue, mouse hippocampal subregions, and more.
Future trends focus on four points: higher resolution (cellular/subcellular), matrix-free/ambient to lower the sample-preparation barrier, AI-assisted image analysis and annotation, and multi-omics integration with transcriptomics/proteomics. The maturation of domestic matrix-free imaging sources is pushing spatial metabolomics from 'exclusive to a few platforms' toward a more accessible norm in research and industry.
To obtain detailed specifications, compatible models, or a quotation for the MSI LDPI / DPI full series imaging ion sources, visit the Neo-Source official website, or contact the official team for compatibility advice tailored to your mass spectrometer (Agilent / SCIEX / Thermo and other mainstream MS).