IHC relies on specific antibodies, usually labeling one or a few proteins in a single experiment, providing high-specificity spatial localization; but it is limited by antibody availability and cross-reactivity, and requires labeling sample preparation (fixation, permeabilization, incubation), which may disturb molecular distribution.
In contrast, mass spectrometry imaging is label-free and can observe hundreds to thousands of molecules simultaneously, but its single-molecule specificity is weaker than antibodies. The two complement each other: mass spectrometry for broad discovery, IHC for targeted confirmation.
A common practice is to perform mass spectrometry imaging and IHC on adjacent/serial sections respectively, then align via morphological registration; or do mass spectrometry first and then stain on the same/adjacent section. The key is to ensure section standardization and coordinate sharing so that the ion image and IHC image can be overlaid and interpreted.
For matrix-free ambient sources (LDPI, DPI, DESI), the short chain of imaging first then staining after sectioning is less disturbing; for MALDI, avoid cross-contamination between matrix and staining.
When mass spectrometry discovers that a molecule is enriched in a specific region, IHC can verify with an independent principle (antigen-antibody) that the protein is indeed located there, enhancing conclusion credibility, especially valuable for biomarker exploration and clinical connection.
Conversely, targets discovered by IHC can also point back to mass spectrometry for unbiased verification or quantitative-trend confirmation, forming bidirectional evidence. It is recommended to reserve an IHC verification step in the study design.
H&E provides general morphological partitioning, IHC provides specific protein localization, and mass spectrometry provides unbiased molecular maps; the three form a multi-layer annotation system. After registration, they can be overlaid and interpreted in SCiLS Lab and MetaboScape to support regional-difference analysis.
Writing serial sectioning + standard registration into the SOP ensures comparability and reproducibility of the molecular, morphological, and targeted three-layer annotation.
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).