Non-decalcified human teeth sample preparation method for MALDI mass spectrometry imaging

Human teeth preserve a rich temporal record of biological and environmental information throughout an individual’s life. Accessing this record requires analytical techniques capable of providing both spatial and chemical resolution. Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) offers powerful capabilities for visualizing the spatial distribution of biomolecules. However, successful analysis demands preservation of both morphology and chemical integrity. The hard and brittle nature of enamel and dentin presents a major challenge, as preparing sufficiently thin sections typically requires decalcification, which can compromise molecular content. In this study, we present a sample preparation method using cryofilm, embedding, and specific cryostat blade angles to enable the analysis of non-decalcified human teeth by MALDI MSI. We further demonstrate this approach using various MALDI matrices, highlighting the potential of this technique for spatial analysis of biomolecules in teeth. This method provides a foundation for future investigations into the spatial and temporal distribution of small molecules in human teeth. • Chemical Imaging of a variety of teeth samples (e.g. molar, canine, deciduous teeth) • Teeth are not chemically altered, enabling direct molecular imaging • This technology can be used for future exposure experiments