Mass spectrometry imaging is powerful, but sample preparation remains a stubborn limitation. Now, researchers have built a nanostructured surface that appears to make the technique far more adaptable – working with everything from whole-plant imprints to stamped fingerprints and cryo-sectioned brain tissue.
The platform combines gold nanoparticle-decorated covalent organic framework (COF) nanofilms with titanium dioxide nanotubes, creating a matrix-free surface for surface-assisted laser desorption/ionization mass spectrometry imaging. In practice, that means cleaner low-mass spectra, stronger ion signals, and compatibility with multiple sample-prep workflows that are usually hard to unify in a single system.
The team used the method to map neonicotinoid pollutants and endogenous metabolites across whole cowpea seedlings, showing that more polar compounds moved faster through plant tissues than less polar ones. They also generated 10-micrometer-resolution lipid maps from stamped fingerprints, capturing fine ridge details, including pores and bifurcations. In cryo-sectioned mouse and rat brains, the platform resolved lipid patterns and metabolic changes linked to focal cerebral ischemia, including ATP depletion and altered sodium-adduct phospholipids in damaged regions.
The authors argue that the substrate’s performance comes from a three-way synergy: plasmonic enhancement from gold nanoparticles, charge-transfer effects from the porphyrin-containing COF, and the ordered nanotube scaffold beneath. Together, those features push matrix-free mass spectrometry imaging closer to being a genuinely universal tool for complex biological samples.
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