Ir-maldesi

The mid-infrared laser deposits energy into water or an ice matrix associated with the sample. This excitation promotes analyte release from the sample into the gas phase without requiring conventional extraction before analysis. The matrix therefore acts as the energy-absorbing component that helps transfer molecules from complex biological materials into a form suitable for mass spectrometric detection.

Electrospray post-ionization converts molecules released by laser-driven desorption into ions that can be analyzed by mass spectrometry. Separating desorption from ionization allows the laser and matrix to focus on releasing sample constituents, while the electrospray plume supplies the ionization step. This combination enables chemical analysis of molecules originating from complex biological samples.

IR-MALDESI supports label-free characterization of several molecular classes, including metabolites, lipids, peptides, and pharmaceuticals. Because the approach analyzes chemical constituents directly, it can examine molecular composition without requiring labels to identify these categories. This breadth makes the technique relevant when multiple types of biomolecules or drug-related compounds must be considered together in tissues, cells, or engineered materials.

When paired with imaging, IR-MALDESI can map where molecular signals occur within a sample rather than reporting only an overall composition. Spatial information helps relate metabolites, lipids, peptides, or pharmaceuticals to particular regions of tissues, cells, or engineered biological materials. The resulting maps can connect molecular distributions with structural organization and functional differences.

A sample such as tissue, cells, or an engineered biological material is positioned for analysis with minimal sample preparation. The infrared laser then excites water or an ice matrix, releasing analytes into the gas phase. An electrospray plume post-ionizes those molecules, and the resulting ions enter a mass spectrometer for chemical measurement or imaging.

Bioengineers can use IR-MALDESI when they need label-free molecular information from biological or engineered samples while preserving spatial context. Applications described for the technique include characterizing tissues, cells, and engineered biological materials, as well as mapping metabolites, lipids, peptides, and pharmaceuticals. These measurements can help relate molecular composition to structure, function, and disease-related changes.