Design of Dendrimer Modified Carbon Nanotubes for Gene Delivery

To investigate the efficiency of polyamidoamine dendrimer grafted carbon nanotube （dendrimer-CNT） mediated entrance of anti-survivin oligonucleotide into MCF-7 cells, and its effects on the growth of MCF-7 cells. Methods： Antisense survivin oligonucleotide was anchored onto polyamidoamine dendrimer grafted carbon nanotubes to form dendrimer-CNT-asODN complex and the complex was characterized by Zeta potential, AFM, TEM, and 1% agarose gel electrophoresis analysis. Dendrimer-CNT-asODN complexes were added into the medium and incubated with MCF-7 cells. MTT method was used to detect the effects of asODN and dendrimer-CNT-asODN on the growth of MCF-7 cells. TEM was used to observe the distribution of dendrimer-CNT-asODN complex within MCF-7 cells. Results： Successful synthesis of dendrimer-CNT-asODN complexes was proved by TEM, AFM and agarose gel electrophoresis. TEM showed that the complexes were located in the cytoplasm, endosome, and lysosome within MCF-7 cells. When dendrimer-CNT-asODN （1.0 μmol/L） and asODN （1.0 μmol/L） were used for 120 h incubation, the inhibitory rates of MCF-7 cells were （28.22±3.5）% for dendrimer-CNT-asODN complex group, （9.23±0.56）% for only asODN group, and （3.44±0.25）% for dendrimer-CNT group. Dendrimer-CNT-asODN complex at 3.0 μmol/L inhibited MCF-7 cells by （30.30±10.62）%, and the inhibitory effects were in a time- and concentration-dependent manner. Conclusion： Dendrimer-CNT nanoparticles may serve as a gene delivery vector with high efficiency, which can bring foreign gene into cancer cells, inhibiting cancer cell proliferation and markedly enhancing the cancer therapy effects.