Novel Gene Drug Carriers Based On One-Dimensional Nanomaterials

Gene therapy has been attractive as a clinical treatment for cancers and genetic disorders during the past20years. Antisense and RNA interference are two effective techniques for gene therapy. Because there is hydrophilic nucleotides skeleton on the surface of antisense oligodeoxynucleotides and small interfering RNA, which are extremely vulnerable to enzyme degradation and can hardly penetrate through cell membrane when administered into human body. Many carriers are used to increase the cellular uptaking rate of the antisense oligodeoxynucleotides and small interfering RNA.In this thesis, the natural one-dimensional nanomaterial halloysite nanotubes were used as the research object, the different methods of functionalization have been used to make the nanotubes applicable as a gene drug carriers, and investigated their transfection efficiency and protective effect of the gene cancer drug. Firstly, in order to be dispersed in the water, halloysite nanotubes were surface modified by different chemical methods, then different gene drugs, including antisense oligodeoxynucleotides and small interfering RNA, were loaded on the functional halloysite nanotubes, to synthesise easy synthetic nano drug carrier systems. Secondly, different fluorescent marker approaches were used to study the intracellular positioning and anti-cancer effect of the constructed gene nanocarriers. Thirdly,novel one-dimensional nanomaterials, carbon nanotubes were investigated as the genetic drug carriers. The main research contents are demonstrated in detailed as follows:1. The hydrolysis of the organosilane was used, coat to halloysite nanotubes with the silicon layer on the surface, which could improve solve their water-soluble.Then antisense oligonucleotides compound onto the functional halloysite nanotubes to form a composite gene medication by electrostatic adsorption. The successful synthesis of the gene carrriers could be proved by means of UV-visible spectroscopy. The MTT, confocal microscopy, flow cytometry and other biological characterization were utilized to study the cell transfection for antisense oligonucleotide delivery efficiency and their toxicity of these gene carriers.The gene drug complex to silencing effects on the survivin gene. The targeting gene has been knocked down by the gene drug complex, and the anti-cancerefficiency has been enhanced.2. A novel multifunctional nanocarrier based on functionalized halloysite nanotubes(HNTs) were developed via electrostatic layer-by-layer assembling approach for loading and intracellular delivery of therapeutic antisurvivin siRNA and simultaneous tracking their intracellular transport, in which PEI-modified HNTs are used as gene vector, anti-survivin siRNA as gene therapeutic agent and mercaptoacetic acid-capped CdSe quantum dots as fluorescent labeling probes. The successful assemblying of the f-HNTs-siRNA complexes were systematically characterized by transmission electron microscopy (TEM), UV-vis spectrophotometry (UV),Zeta potential measurement, fluorescence spectrophotometry, and electrochemical impedance spectroscopy (EIS). Confocal microscopy, biologiacl TEM and flow metery studies revealed that the complexes enabled the efficient intracellular delivery of siRNA for cell-specific gene silencing. In vitro cytotoxicity studies of the complxes using the MTT assay exhibit enhanced antitumor activity. Furthermore, HNTs mediated siRNA delivery effectively knocked down gene expression of survivin and thereby decreased the levels of target proteins of PANC-1cells. Therefore, this study confirms the potential of HNTs as a new effective drug delivery system in the applictions of cancer gene treatment.3. The one-dimensional nanomaterials carbon nanotube as gene drug delivery carrier were prelimiting studied cationic polymer PEI functionaliz carbon nanotubes to improve its water solubility and biocompatibility, and its relatively high cytotoxicity. Confocal microscopy, cell TEM characterization methods were used to study the effect of the gene drug composite.By comparing with naked small interfering RNA and functionalized carbon nanotubes,it can proved that the anti-cancer drug carrier could improve the intercellur.