Anionic LPD complexes for gene delivery to macrophage: Preparation, characterization and transfection in vitro

Abstract

In the present study, anionic lipid/peptide/DNA (LPD) complexes consisting of pH-sensitive liposome and protamine were introduced as the carriers targeting RAW 264.7 cell line, which had been reported to be difficult for transfection. The LPD complexes were physically characterized. The pH sensitivities and sizes of liposomes were investigated. The zeta potentials of LPD complexes altered significantly with the addition of protamine sulfate and anionic liposomes. It was demonstrated that the carriers produced an increase in the stability of plasmid DNA against DNase I. The TEM showed that the size distribution of LPD complexes was irregular. In the in vitro transfection, the efficiency of LPD complexes was higher than that of Lipofectamine™ 2000 and protamine/DNA complexes, but lower than that of electroporation. A possible mechanism for the internalization of plasmid DNA mediated by the anionic LPD complexes was also proposed. With a high safety certificated by MTT assay, LPD complexes prepared in this study might be potentially employed as a macrophage gene therapy.

Keywords::

• pH-sensitive liposome
• macrophage
• transfection
• LPD complexes
• gene carriers

Acknowledgements

We are grateful to associate Professor Hongyang Gao and Professor Weiyue Lu for their technical guidance. We also thank Jieqi Luo, Wei Chen and Zhiwen Zhang for their technical assistance.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.