Importance of the Phospholipid Core for Mucin Hydrogel Penetration and Mucosal Cell Uptake of Maltodextrin Nanoparticles.

Nanoparticles (NPs) used as mucosal antigen delivery systems are a promising way to vaccinate. However, NPs have to cross the mucus gel and penetrate into mucosal cells to deliver antigens, and a mismatch exists between mucopenetrating NPs, rarely able to interact with cells, and NPs designed to deliver antigens into cells, but often described as mucoadhesives. Here, we compared the ability of cationic maltodextrin-based NPs, either without (NP + ) or with an anionic phospholipid core (NPL), to interact with mucins and airway epithelial cells. We showed that their lipid core increased the NPL's mobility in mucin hydrogel by reducing interactions with mucins. Similarly, the uptake and protein delivery by NPLs into airway epithelial cells were not hindered by mucins. This highlights the importance of anionic lipids in the NPL, which are more efficient in crossing the mucin hydrogel while retaining the ability to interact with epithelial cells, an intermediate behavior between mucoadhesive and mucopenetrating NPs.