Abstract: Objective To evaluate whether the expressing vector pGenesil-1 encoding enhanced green fluorescent protein (EGFP) could be transfected into A549 human lung cancer cells mediated by nano-hydroxyapatite (nHAP) and to determine the transfection efficiency. Methods The nHAP was synthesized by the homogeneous precipitation method. The structure of the nanoparticles was observed under transmission electron microscope. The nHAP was prepared using ultrasonication and Na2CO3 and was modified with poly-L-lysine (PLL) at pH 7.4. The transfection of pGenesil-1 into A549 was divided into three groups as follows: nHAP-PLL group (n=8) mediated by nano-hydroxyapatite modified with poly-L-lysine (nHAP-PLL), liposome group (n=8) mediated by Lipofectamine and control group (n=8). After 48 hours transfection, the expression of EGFP was observed with fluorescent microscope. Flow cytometry was used to detect the transfection rate of each group. Results Under transmission electron microscope, the synthesized product presented needle-like and well dispersed particles with evenly distributed sizes of (15~20nm)×(60~80nm). Under fluorescent microscope, the expression of EGFP was detected in A549 cells of nHAP-PLL group and liposome group while no expression of EGFP was seen in A549 cells of control group at 48 hours post transfection. Flow cytometry analyses showed that, the transfection rate of A549 cells was (31.8±1.9)% of nHAP-PLL group and (33.4±3.7)% of liposome group. Compared with the control group, there was significant difference respectively (P<0.01), but there was no significant difference of transfection rate between nHAP-PLL group and liposome group (P>0.01). Conclusion The nHAP modified with poly-L-lysine can mediate the transfection of plasmid into A549 human lung cancer cells.

Key words: Hydroxyapatite, Nanoparticles, Poly-L-lysine, Transfection efficiency, A549 cell