The Gene Delivery Mediated By The Calcium-polybenzimidazole Complexes

Gene carrier is the core technology in gene therapy. The common gene carrier can be divided into virus and nonvirus carrier. In contrast to virus carrier, nonvirus carrier has the specific targeting property, good biocompatibility and the huge potential, so it attracts more and more attention of scientists.In this work,we synthesized four calcium complexes, and systematically studied the gene carrier in vitro and biological properties of the cell.In the part of synthesis,we chosed edtb, ntb, ctb as primary ligands.The three ligands react with two metal calcium salt Ca(NO3)2-4H2O, Ca(Ac)2·H2O, getting four complexes. Meanwhile,the X-ray single crystal diffraction is utilized to analysis the structure of the complexes.In biological properties parts,we use the UV-visible spectroscopy, the means of RALS, DLS to test the combination between complexes and DNA.We detect the influence of DNA concentration, complexes concentration and reaction time on DNA condensation. The results suggest that at pH7.4,the size of condensates gradually become large with increasing complexes concentration and reaction time.We test the aggregates morphology through the transmission electron microscopy (TEM) at different molar complex/DNA ratios.The structure of the loose aggregate gets into dense and orderly condensation.The MTT method is used to detect the toxicity of Cu (II)、 Co (II)、 Ca (II) three complexes and DNA aggregates for cancer cells(HeLa cells) and normal cells (COS7cells).The results show that, compared with the Cu (II), Co (II) metal complexes, the toxicity of Ca (II) complexes significantly reduced, and the toxicity of normal cells is lower than the cancer cells. Transmembrane experiment showes the aggregates can get across the cell membrane.Through the green fluorescent protein expression (pEGFP) and luciferase (pGL3),we found that complexes can deliver gene into the the cells and transfer,but the efficiency of transfection is not high. When in the presence of DOPE or CQ, the transfection efficiency can be greatly improved.