The SMA workflow and quality control designnonembedded, snap-frozen samples are sectioned and thaw-mounted onto noncharged, barcoded Visium Gene Expression arrays. Tissue sections are then sprayed with MALDI matrices and MSI is performed. This is followed by H&E staining and imaging with bright field microscopy. Finally, sections are processed for SRT. We also designed the following three types of control samples: (1) MSIsamples processed with standard MALDI-MSI protocol on ITO conductive slides; (2) VISIUMsamples processed with standard Visium protocol on all four capture areas of a Visium Gene Expression array and (3) ViCTRLsamples processed with Visium protocol, but MALDI-MSI was performed on other capture areas of a Visium Gene Expression array.
