Enhanced gene delivery by polyethyleneimine coated mesoporous silica nanoparticles

Due to large surface area, tunable pore size, easy surface manipulation, and low-toxicity mesoporous silica nanoparticles (MSNs) may act as a suitable vector for gene delivery. In order to make MSNs as a suitable gene delivery system, we modified the surface of phosphonated MSNs (PMSN) with polyethyleneimine (PEI) 10 and 25 KDa. Then nanoparticles were loaded with chloroquine (CQ) (a lysosomotropic agent) and complexed with plasmid DNA. The transfection efficiency and cytotoxicity of these nanoparticles was examined using green fluorescent protein plasmid (pGFP) and cytotoxicity assay. All PEI coated nanoparticles showed positive zeta potential and mean size was ranged between 170 and 215 nm with polydispersity index bellow 0.35. PEI-coated MSNs significiantly enhanced GFP gene expression in Neuro-2 A cells compared to PEI 10 and 25 KDa. The results of the cytotoxicity assays showed that these nanoparticles have an acceptable level of viability but CQ loaded nanoparticles showed higher cytotoxicity and lower transfection activity than CQ free nanoparticles.