Protocol for preparing small, fragile samples from Schistosoma mansoni and Drosophila melanogaster brains for MALDI mass spectrometry imaging.

Mass spectrometry imaging is a routine tool for investigating biological samples with high spatial and mass resolution. However, sample preparation, especially when dealing with very small samples, can be challenging. Here, we describe a sample preparation protocol for small and fragile samples based on examples of Schistosoma mansoni parasites and dissected Drosophila melanogaster brains. We describe steps for cryosectioning, matrix application, measurement, and data analysis to enable the acquisition of high-quality spatial lipidomics and metabolomics data from small samples. For complete details on the use and execution of this protocol, please refer to Mokosch et al. and Rorsman et al., respectively.1,2.