Design of dendrimer modified carbon nanotubes for gene delivery

Objective: 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 mu mol/ L) and asODN ( 1.0 mu mol/ 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 mu mol/ L inhibited MCF- 7 cells by ( 30.30 mu 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.