Lipid nanoparticles (LNPs) are increasingly finding applications in targeted drug delivery, including for subcutaneous, intravenous and vaccine administration. While a variety of microscopy techniques are widely used for LNP characterization, their resolution does not allow for characterization of the spatial organization of different components, such as the excipients, targeting agents, or even the active ingredient. Herein, we present a nanoimaging approach to probe the spatial organization of individual constituents of multi-component LNPs used for siRNA-based drug delivery by multinuclear solid-state magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy. We exploit dynamic nuclear polarization (DNP) for sensitivity enhancement to detect functionally important LNP constituents, the siRNA and the targeting agent (< 1-2 w/v%), and achieve a 3D structural model of the LNP. The integrated nanoimaging approach presented here is applicable for structural analysis of a wide range of lipid nanoparticles and can be extended more generally to other multi-component biologicals formulations.
