Localisation of Biomarkers in Tissue

The MALDI Molecular ImagerTM investigates the molecular composition of tissue sections with a resolution of 2050 ?m. From each point of the tissue, mass spectra of the molecular composition are generated by the MALDI process in a mass spectrometer. These molecular mass spectra of spatially resolved ions are then evaluated by powerful software for the existence of certain mass signals and for biostatistic analysis.

The MALDI Process Localises Compounds in Tissue
Mass spectra are generated by ionisation of molecules by a laser with the assistance of a matrix (MALDI = matrix-assisted laser desorption/ionisation) and measurement of the time of flight (TOF) of the ions after a pulsed acceleration. MALDI imaging is a fast and reliable screening tool for direct damage-free analysis of proteins and compounds accelerating biomarker discovery and chemical compound monitoring in tissue (fig. 1).

Mass Imaging to Depict Protein Expression
Analysis of the complex data set can be performed by dedicated selection and false colour depiction of single masses. Peaks height correlates with colours brightness/intensity. The resulting protein map enables the analysis of direct tissue protein expression without any labelling technique.

Tissue Profiling: Detection of Biomarker Candidates
The MALDI Molecular Imager solution is capable for generation of a tissue class discriminating algorithm. The reliability of classification is defined by percentage values for specificity and sensitivity. Classification itself by using the validated algorithm can be performed with both, new & unknown specimen. In addition, the results can be visualised by depicting the corres­ponding tissue classes in false colour mode (fig.2).