Effects of grafting cell penetrate peptide and RGD on endocytosis and biological effects of Mg-CaPNPs-CKIP-1 siRNA carrier system in vitro

Calcium phosphate nanoparticles (CaPNPs) have good biocompatibility as gene carriers; however, CaPNPs typically exhibit a low transfection efficiency. Cell penetrate peptide (TAT) can increase the uptake of nanoparticles but is limited by its non-specificity. Grafting adhesion peptide adhesion peptide on carriers can enhance their targeting. The Plekho1 gene encodes casein kinase-2 interacting protein-1 (CKIP-1) , which can negatively regulate osteogenic differentiation. Based on the above, we produced a Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system via hydrothermal synthesis, silanization and adsorption. The effects of this carrier system on cell endocytosis and biological effects were evaluated by cell culture in vitro. The results demonstrate that CaPNPs with 7% Mg (60 nm particle size, short rod shape and good dispersion) were suitable for use as gene carriers. The carrier system boosted the endocytosis of MG63 cells and was helpful for promoting the differentiation of osteoblasts, and the dual-ligand system possessed a synergistic effect. The findings of this study show the tremendous potential of the Mg-CaPNPs-RGD-TAT-CKIP-1 siRNA carrier system for efficient delivery into cells and osteogenesis inducement.