An efficient calcium phosphate nanoparticle-based nonviral vector for gene delivery

Abstract

Background

Smaller nanoparticles facilitate the delivery of DNA into cells through endocytosis and improve transfection efficiency. The aim of this study was to determine whether protamine sulfate-coated calcium phosphate (PS-CaP) could stabilize particle size and enhance transfection efficiency.

Methods

pEGFP-C1 green fluorescence protein was employed as an indicator of transfection efficiency. Atomic force microscopy was used to evaluate the morphology and the size of the particles, and an MTT assay was introduced to detect cell viability and inhibition. The classical calcium phosphate method was used as the control.

Results

Atomic force microscopy images showed that the PS-CaP were much smaller than classical calcium phosphate particles. In 293 FT, HEK 293, and NIH 3T3 cells, the transfection efficiency of PS-CaP was higher than for the classical calcium phosphate particles. The difference in efficiencies implies that the smaller nanoparticles may promote the delivery of DNA into cells through endocytosis and could improve transfection efficiency. In addition, PS-CaP could be used to transfect HEK 293 cells after one week of storage at 4°C with a lesser extent of efficiency loss compared with classical calcium phosphate, indicating that protamine sulfate may increase the stability of calcium phosphate nanoparticles. The cell viability inhibition assay indicated that both nanoparticles show similar low cell toxicity.

Conclusion

PS-CaP can be used as a better nonviral transfection vector compared with classical calcium phosphate.

Keywords:

• transfection efficiency
• particle size
• protamine sulfate
• stability

Acknowledgements

This study was supported by the 863 Project of the Ministry of Science and Technique of China (Grant 2007AA02Z172), the Postdoctoral Science Foundation of China (Grant 20100471217), the Scientific Research Fund of Hunan Provincial Education Department (Grant 09C621), the Postdoctoral Science Research Fund of Hunan Provincial Science and Technique Department (Grant 2009RS3015), the Open Fund of the Key Laboratory of the Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), and Hunan Normal University (Grant KLCBTCMR2009-12).

Disclosure

The authors report no conflicts of interest in this work.