Polyethylenimine-immobilized core–shell nanoparticles: Synthesis, characterization, and biocompatibility test

Herein, we prepared PEI-immobilized core–shell particles possessing various types of polymer cores via a visible light-induced surfactant-free emulsion polymerization (SFEP) of three vinyl monomers: styrene (St), methyl methacrylate (MMA), and 2-hydroxyethyl methacrylate (HEMA). An effect of monomers on the polymerization and characteristics of resulting products was investigated. Monomers with high polarity can provide high monomer conversion, high percentage of grafted PEI, stable particles with uniform size distribution but less amino groups per particles. All prepared nanoparticles exhibited a core–shell nanostructure, containing PEI on the shell with hydrodynamic size around 140–230 nm. For in-vitro study in Caco-2 cells, we found that the incorporation of PEI into these core–shell nanoparticles can significantly reduce its cytotoxic effect and also be able to internalized within the cells. Accordingly, these biocompatible particles would be useful for various biomedical applications, including gene transfection and intracellular drug delivery.