Evaluation of Oil-Absorbing Film for Imprint Desorption Electrospray Ionization Mass Spectrometry Imaging (IDESI-MSI) on Biological Samples.

Imprint Desorption Electrospray Ionization Mass Spectrometry Imaging (IDESI-MSI) has proven to be a robust and reliable tool for chemically imaging biological samples such as fungi, animal tissues, and plants, but the choice of the imprint substrate is crucial. It must effectively transfer maximum amounts of species from the sample while preserving the original spatial distribution of detected molecules. In this study, we explored the potential of utilizing an oil-absorbing film, known for its soft nature and excellent lipophilicity, as an imprint substrate for IDESI-MSI on biological samples. To assess the transfer efficiency of the amounts of molecules and molecular patterns, we conducted experiments using mouse brain tissue. The result shows that more than 90% of the analytes can be transferred to the oil-absorbing film from the original tissue. A comparison of IDESI-MSI results between the oil-absorbing film and the original tissue demonstrates the material's capability to transfer most molecules from the original tissue and retain images of different analytes with high spatial fidelity. We extended our investigation to plant imaging, where we applied IDESI-MSI to a cross-section of okra. The oil-absorbing film exhibited promise in this context as well. These findings suggest that IDESI-MSI utilizing the oil-absorbing film holds potential across various research fields, including biological metabolism, chemistry, and clinical research, making this technique widely applicable.