Preparation of PEI‐modified nanoparticles by dopamine self‐polymerization for efficient DNA delivery

Abstract Achieving efficient and safe gene delivery is of great significance to promote the development of gene therapy. In this work, a polydopamine (PDA) layer was coated on the surface of Fe 3 O 4 nanoparticles (NPs) by dopamine (DA) self‐polymerization, and then magnetic Fe 3 O 4 NPs were prepared by the Michael addition between amino groups in polyethyleneimine (PEI) and PDA. The prepared Fe 3 O 4 NPs (named Fe 3 O 4 @PDA@PEI) were characterized by Fourier transform infrared (FTIR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). As an efficient and safe gene carrier, the potential of Fe 3 O 4 @PDA@PEI was evaluated by agarose gel electrophoresis, 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, fluorescence microscopy, and flow cytometry. The results show that the Fe 3 O 4 @PDA@PEI NPs are stable hydrophilic NPs with a particle size of 50–150 nm. It can efficiently condense DNA at low N/P ratios and protect it from nuclease degradation. In addition, the Fe 3 O 4 @PDA@PEI NPs have higher safety than PEI. Further, the Fe 3 O 4 @PDA@PEI/DNA polyplexes could be effectively absorbed by cells and successfully transfected and exhibit higher cellular uptake and gene transfection efficiency than PEI/DNA polyplexes. The findings indicate that the Fe 3 O 4 @PDA@PEI NPs have the potential to be developed into a novel gene vector.