Multiplexed spatial screening of lipid-based nanoparticles for extrahepatic messenger RNA targeting.

Lipid-based and other types of nanoparticles (NPs) enable target- and organ-specific, efficient extrahepatic delivery of synthetic messenger RNA (mRNA) or other cargos in vivo. However, clinical translation of targeting mRNA NP products is hampered by the lack of detailed control of targeting selectivity. Here, we introduce multimodal bioluminescence and mass spectrometry imaging (MSI) for active nanoparticle multiplex screening. It combines luminescence and fluorescence imaging on an organ and cellular level, respectively, as functional readouts of the mRNA payload with direct multiplexed assessment of the tissue distribution of lipids from NPs by MSI. This analytical procedure generates organ-specific multimodal information on NP activity and selectivity. Deuteration allows simultaneous spatial mapping of the distribution of different NPs comprising the identical lipids, here demonstrated using lung- and spleen-targeting lipoplex formulations administered to the same mouse. The combination of molecular histology and immunofluorescence microscopy analysis provides a target cell type-specific readout of the NP. Such detailed information allows to gain more profound insight into structure-function-relationships, and will facilitate pharmaceutical development of next generation NPs for extrahepatic organ-specific targeting.