Microfluidic Synthesis of Quaternary Chitosan Coated Liposome to Enhance Cellular Uptake and In Vivo Immune Responses

This study relates to positively surface-charged liposomes ((+)-LPS) coated with cationic polyelectrolytes via covalent bonds and the preparation method and applications thereof. This nanosized (+)-LPS was synthesized via a single-step microfluidic process, in which the formation of LPS and the coating of N-[(2-hydroxy-3-trimethylammonium)propylchitosan (HTCC) on the surface via covalent bonds were completed in situ. Flow cytometric endocytosis analysis of (+)-LPS on JAWS II dendritic cells demonstrated that HTCC coated via covalent bonds showed higher uptake efficiency than those coated via hydrogen bonds and increased uptake by 100-fold compared to LPS without HTCC coating. HTCC-coated LPS, via covalent binding, also reduced the cytotoxicity after incubation with JAWS II cells. In vivo experiments showed that BALB/c mice vaccinated with anthrax vaccine adsorbed (AVA) mixed with HTCC-covalently coated (+)-LPS could induce IgG anti-PA antibodies in a shorter time and at a higher level than mice vaccinated with AVA plus (+)-LPS coated with HTCC via hydrogen bonds and AVA only and that the humoral immune response was more dominant. Moreover, the preparation process allows rapid and high-quality production of (+)-LPS with low cost and simple operation. Thus, the present disclosure is competitive with practicability, providing an advantage in commercialization.