Preparation of a Mimetic Tissue Model for Mass Spectrometry Imaging Experiments. v1

This protocol describes the preparation of a mimetic tissue model for mass spectrometry imaging (MSI) applications, suitable for both MALDI-MSI and DESI-MSI workflows. The method involves cryogenic homogenisation of biological tissue, controlled spiking of analyte standards or internal standards, and moulding into a frozen plug that closely mimics the physicochemical and ionisation properties of native tissue. The resulting mimetic tissue model enables optimisation of matrix selection, matrix application parameters, and instrument settings, and supports the generation of calibration curves for qualitative and quantitative MSI analyses. When implemented correctly, this protocol produces homogeneous, reproducible tissue standards that can be used as quality control samples to assess analytical performance, signal stability, and inter- and intra-batch variability across extended MSI experiments.