Preparation Of PAMAM Dendrimer Nano Assembly System And Its Application In Gene Delivery

Polyamidoamine (PAMAM) dendrimer is an important member of nanomaterials. PAMAM dendrimer has excellent physical and chemical properties. In this paper, we study the assembly systems of PAMAM dendrimer and nucleic acids, and their application in gene delivery system.(1) Synthesis and characterization of PAMAM dendrimers.(2) Preparation of PAMAM dendrimer and carbon nanotube (CNT) assembly system.(3) Preparation of PAMAM dendrimer and gold nanorods (GNR) assembly system.We used 1H NMR, FT-IR, AMF, HR-TEM to characterize the PAMAM dendrimer and their assembly nanosystem.(4) PAMAM dendrimer deliver anti-sense gene to cancer cells.(5) PAMAM-CNT assembly nanosystem deliver anti-sense gene to cancer cells.(6) PAMAM-GNR assembly nanosystem deliver small interfering RNA to cancer cells.PAMAM-DNA, PAMAM-CNT-DNA, and PAMAM-GNR-siRNA can be formed by mixing nanosystem with DNA or siRNA molecues. PAMAM-CNT-DNA, PAMAM-GNR-siRNA, or PAMAM-DNA were added to the culture bottle with cancer cells, and together incubated for 1-4 days. Agrose gel electrophoresis was used to comfirme the formation of nanosystem-asODN or siRNA complex. MTT analysis was used to investigate the proliferation of cancer cells in the presence of nanocomposition. RT-PCR was used to invetigate the gene expression level. Confocol microscopy was used to observe the internalization of nanocomposition. TEM was used to comfirmed the location of nanocomposition within the cancer cells.In conclusion:the structure and purity of PAMMA moleucles were characterized by using ~1H NMR and FT-IR. AFM images showed that PAMAM can be bound to CNT and dGN, and finally form the nanocompsoition. HR-TEM images showed that PAMAM-CNT and PAMAM-GNR nanocomposition could be used to deliver anti-sense nucleic acids into cancer cells with very low cell toxicity. Fluorescence Confocol Microscope observation and MTT analysis proved that PAMAM, PAMAM-CNT, and PAMAM-GNR nanocompositions can deliver survivin asODN/siRNA into cancer cells, and significantly inhibited the growth of cancer cells such as HepG2 cells and MGC80-3 cells. The inhibition rates increased accordingly as the incubation time, nanocomposition concentration and generation of PAMAM increased and the highest rate is to 55% when the concentration of G4.0 PAMAM-asODN is 6.0μmol/L after incubating with the cells for 96h. The G5.0 PAMAM dendrimer-modiifed CNTs and GNR were confirmed to exhibit the maximum gene delivery efficiency for cancer cells tested. So, we consider that PAMAM-GNR/CNT nanocompositions may be good gene delivery system for cancer therapy, and have potential application in gene /drug delivery for cancer therapy.