Preparation and characterization of magnetic PEG-PEI-PLA-PEI-PEG/Fe3O4-PCL/DNA micelles for gene delivery into MCF-7 cells

Abstract

Targeted drug delivery to cancer tissues by micelles holds great promise for cancer therapy and diagnosis. In this study, the ability of folic acid (FA)- polyethylene glycol (PEG)- polyethyleneimine (PEI)-polylactic acid (PLA) (FA-PEG-PEI-PLA-PEI-PEG-FA) (PLEEF), Fe3O4-PEI-polycaprolactone (FePEC), FePEC/PLEEF (FePECLEF), and FePEC/PLEEF/EPPT peptide (FePECLEFE) micelles for gene delivery into the MCF-7 cells was evaluated. FePEC/DNA, PLEEF/DNA, FePECLEF/DNA, and FePECLEFE/DNA micelles were prepared using solvent evaporation technique. The morphology, size, and surface charge of micelles were investigated using transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. The ability of FePEC, PLEEF, FePECLEF, and FePECLEFE micelles to neutralize the negative charge of DNA and protect it against restriction enzymes was also investigated by agarose gel electrophoresis. The results showed that the FePECLEFE/DNA micelles had a spherical morphology with particle size about 200–300 nm. The agarose gel electrophoresis results revealed that the FePEC/DNA, PLEEF/DNA, FePECLEF/DNA, and FePECLEFE/DNA micelles have a high-ability to neutralize the negative charge of DNA and protect it against restriction enzymes. In this study, MTT assay was used to investigate the biocompatibility of micelles. The results indicated that the micelles have low cytotoxicity and good biocompatibility. In vitro transfection assays revealed that gene transfer efficiency was higher in the FePECLEFE/DNA compared to other micelles in the serum-containing medium and serum-free medium. Flow cytometry results showed that the highest gene transfer efficiency in free serum and the serum-containing medium was observed in FePECLEFEd/DNA micelles (46.5 ± 3.12 and 47.24 ± 9.4%, respectively).