Enhanced gene delivery of low molecular weight PEI by flower-like ZnO microparticles

Low molecular weight (1.8 kDa) branched polyethylenimine (PEI) has been used as non-viral vector for gene delivery because of its low toxicity, however, its further application in biomedical field has been restricted due to its low gene transfection efficiency. Herein, ZnO microflowers were prepared to increase the gene expression level mediated by PEI. Four methods have been applied to tune the shape of ZnO microstructures. Scanning electron microscopy (SEM) demonstrated the successful preparation of four kinds of flower like ZnO microparticles. By loading PEI/pDNA into ZnO microparticles, the formed new complexes showed enhanced gene transfection compared to PEI/pDNA alone. Cell uptaking experiments explained a possible mechanism that the tips of ZnO microflowers penetrated into the surface of cells, thus facilitating the entry of gene cargo into cells. These findings highlight the potential of needle like microstructure as adjuvant for efficient biomacromolecular delivery.