Comparison Of The Vector Capacity Of Different Modified Hydroxyapatite Nanoparticles As Gene Vectors

Objective: To develop safer and more effective non-viral gene vectors, the vector capacities of ten kinds of newly modified hydroxyapatite (HAT) nanoparticles were evaluated. Method: Transmission electron microscopy of the HAT nanoparticles was performed, and their suspension stability observed under the room temperature. Ten kinds of modified HAT nanoparticles were observed and determined in condition of different power of hydrogen or different HAT concentrations for their capacity of DNA binding, DNA protection and in vitro transfection efficiency, for their biocompatibility with Hela cells (cell colony experiment), and also for their sterization method. Results: Ten kinds of modified HAT nanoparticles showed a good capacity of DNA binding in a wide range of pH values. HAT nanoparticles surface-modified by Polyethylenimine (PEI) or other surfactant have better DNA-binding performance. Yet, HAT nanoparticles without modification by Polyethylenimine or other surfactant have poor suspension stability and could not bind DNA completely when used in relatively lower concentrations. No obvious cytotoxicity of all the ten HAT nanoparticles was revealed in working concentration (transfection concentration) by cell cloning experiment. However, HAT nanoparticles modified by PEI or other dispersant showed significant cytotoxicity when used in the concentration of higher than 1500μg/ml. We have found that transfection efficiency of the eighth HAT nanoparticle was the highest, which was about 20% in cervical cancer cells (Hela cells) and 35% in nasopharyngeal carcinoma cells (CNE-1 strain). The transfection efficiency of liposome as the control group was approximately 70% in cervical cancer cells and 85% in nasopharyngeal carcinoma cells (CNE-1 strain). There was no significant expansion change in size for HAT nanoparticles at high temperature sterilization observed under TEM. Conclusion: Ten kinds of modified HAT nanoparticles showed a good capacity of DNA-binding in a wide range of pH values, and showed a good biocompatibility with Hela cells in the transfection concentration. Although the transfection efficiency of the eighth HAT nanoparticles in Hela cells was slightly higher than that of the nanoparticles used in our former studies, the transfection efficiency of HAT nanoparticles remains to be further improved compared with liposomes. The sterilization test indicates that high temperature sterilization for HAT nanoparticles was a reliable, simple and feasible method.