Hydroxylapatite nanorods: an efficient and promising carrier for gene transfection.

Calcium phosphate (CaP) has been used as the vector for gene transfection in the past three decades with the characteristics of excellent biocompatibility and biodegradability. However, clinical application of calcium phosphate is still not popular due to poor-controlling of DNA/CaP complex preparation and its low transfection efficiency. In this study, block copolymer (PLGA-mPEG) assisted synthesis of hydroxylapatite (HAP) nanorods and DNA post-adsorbing method for transfection in vitro have been reported. By hydrothermal treatment, HAP nanorods with relatively uniform sizes of ~100 nm in length and ~25 nm in diameter and high crystallinity were prepared, which were characterized by TEM, XRD and FTIR measurements. In the presence of Ca(2+) (0.2 mol/L), HAP nanorods showed ultra-high DNA loading capacity, which was significantly enhanced by one or two magnitude compared with the recently reported high loading capacity mesoporous silica vectors. HAP nanorods, therefore, have a great potential as the gene vector to deliver DNA into the cells effectively and safely.