Polyethyleneimine functionalized polymer microsphere: a novel delivery vector for cells

Monodisperse poly(ethylene glycol dimethacrylate-co-methacrylic acid) (P(EGDMA-co-MAA)) microspheres with two different diameters (69 and 160 nm) were facilely synthesized via distillation precipitation polymerization in neat acetonitrile, and these microspheres interacted with the amino groups of polyethyleneimine (PEI) chains though hydrogen-bonding as well as electrostatic interactions to form PEI-functionalized (P(EGDMA-co-MAA)). The successful modification of P(EGDMA-co-MAA) microspheres with PEI was confirmed by dynamic light scattering (DLS) and agarose gel electrophoresis. The in vitro gene transfection was evaluated by co-culturing human embryonic kidney (HEK) 293T cells and P(EGDMA-co-MAA) microsphere/plasmid DNA (pDNA) complexes, and the results were determined by fluorescence microscopy. Furthermore, the cytotoxicity of PEI-functionalized P(EGDMA-co-MAA) microspheres was assessed via MTT assay and FDA–PI staining. The PEI-functionalized (P(EGDMA-co-MAA) provides a potential novel delivery vector for cells.