Excipient-Free Ionizable Polyester Nanoparticles for Lung-Selective and Innate Immune Cell Plasmid DNA and mRNA Transfection

Abstract

Extrahepatic nucleic acid delivery using polymers typically requires the synthesis and purification of custom monomers, post-synthetic modifications, and incorporation of additional excipients to augment their stability, endosomal escape, and in vivo effectiveness. Here, we report the development of a single-component and excipient-free, polyester-based nucleic acid delivery nanoparticle platform comprising ionizable N-methyldiethanolamine (MDET) and various hydrophobic alkyl diols (Cp) that achieves lung-selective nucleic acid transfection in vivo. PolyMDET and polyMDET-Cp polyplexes displayed high serum and enzymatic stability, while delivering pDNA or mRNA to "hard-to-transfect" innate immune cells. PolyMDET-C4 and polyMDET-C6 mediated high protein expression in lung alveolar macrophages and dendritic cells without inducing tissue damage or systemic inflammatory responses. Improved strategies using readily available starting materials to produce a simple, excipient-free, non-viral nucleic acid delivery platform with lung-selective and innate immune cell tropism has the potential to expedite clinical deployment of polymer-based genetic medicines.

mRNA nanodelivery systems: targeting strategies and administration routes

“…Interestingly, the pKa of hydrophobic ionizable polyester targeting pulmonary immune cells was found to be less than five, contrary to the result of pKa > 9 observed in LNPs (Fig. 10 B) [ 168 ]. It could be relevant to the difference in intracellular endocytosis pathways.…”

“…Like the LNPs, cationic polymers are widely used in targeted pulmonary delivery strategies. Commonly used cationic polymers include PEI [ 147 , 164 ], PBAEs [ 148 – 150 , 165 ], and polyester materials [ 151 , 166 – 168 ]. PEI is widely used as a cationic polymer carrier for nucleic acid delivery [ 60 , 169 ].…”

“…B Schematic illustration of the ionizable polyester nanoparticles (polyMDET or polyMDET-Cp) for lung-selective nucleic acid transfection. Reproduced with permission [ 168 ]. Copyright 2022, American Chemical Society.…”

Nanoparticles‐induced potential toxicity on human health: Applications, toxicity mechanisms, and evaluation models

“…When NPs are deposited in the respiratory system, they can interact with different types of lung cells, such as alveolar macrophages, epithelial cells, and fibroblasts. These cells can recognize and engulf NPs through phagocytosis or pinocytosis 113 . The uptake of NPs can trigger a series of cellular responses, such as the generation of ROS, the release of cytokines, and activation of inflammatory pathways.…”

“…These cells can recognize and engulf NPs through phagocytosis or pinocytosis. 113 The uptake of NPs can trigger a series of cellular responses, such as the generation of ROS, the release of cytokines, and activation of inflammatory pathways. Cellular responses to NP exposure are highly dependent on particle size, surface chemistry, and dose.…”