Studies On Cancer Therapy Based On Functional Pd@Au Nanoparticles

With the development of nanotechnology,more and more nanomaterials are used in different treatment models of tumors.Metal nano-materials have obtained more attention owing to the advantages of good biocompatibility,chemical inertness,surface plasmon resonance(SPR)absorption and easy modification.As one of the representatives,the core-shell bimetallic nanomaterials have the higher photothermal conversion efficiency than that of monometal nanomaterials.This property makes bimetallic nanomaterials to be the promising photothermal nanomaterials.Compared with monometal nanomaterials and traditional bimetallic nanoparticles,the core-shell bimetallic particles have special electronic structure and surface properties,which not only maintain the physical and chemical properties of the original metal nuclei,but also have excellent metal properties of the shell metal nanomaterial.Under the synergistic effect of the two metals,bimetallic nanomaterials have more excellent special properties.However,metal nano-materials as a new type of photothermal conversion reagent only has excellent light and heat conversion properties,and still have some limitations in tumor targeted therapy and in vivo transportion.Therefore,a new type of core-shell Pd@Au nanoparticles are prepared by oxidation-reduction method in this paper.The following studies are focoused on functional Pd@Au nanoparticles and the main research aspects are listed as follow:1.A metal-organic framework based nanocomposite with co-encapsulating of Pd@Au nanoparticles and doxorubicin for pH-and near-Infrared light-triggered synergistic chemo-photothermal treatment of cancer cellsIn order to improve the limitation of single treatment mode,we took a novel and effective method to synthesis Pd@Au bimetallic nanoparticle,and subsequently combined ZIF-8 and antitumor drug to construct a pH-and NIR-responsive multifunctional system for chemothermal synergistic tumor therapy.In this system,Pd@Au nanoparticles and antitumor drugs were simultaneously loaded on ZIF-8 material by one-step synthesis under physiological conditions(pH 7.4),the ZIF-8 can strongly inhibit the release of encapsulated DOX.However,under acid conditions,the ZIF-8 is unstable and has subsequently degraded,leading to the release of loaded DOX and the chemotherapy of cancer cells.Moreover,by irradiated with NIR laser,the present Pd@Au nanoparticles exhibited the high efficiency for converting NIR laser into heat,not only promoting the release of DOX,but also realizing the chemothermal synergistic tumor therapy.In vitro results demonstrated that this system has an obvious cytotoxicity for SMMC-7721 cells,and this cytotoxicity is higher than that of monotherapy.With these advantages,we believe that such a versatile synergistic therapy system will open a new horizon to design multifunctional systems for synergistic tumor therapy.2.Aptamer-functionalized Pd@Au nanostructures for targeted therapy of tumorsAs a common material for tumor photothermal therapy,metal nanoparticles still have a series of deficiencies such as weak targeting and high synthesis cost.To overcome this problems,a multifunctional nanocomposite system with excellent targeting,high efficacy and excellent sensitivitproy was developed for the targeted therapy of tumor under the use of nucleic acid aptamers which have low immunogenicity,easy synthesis and low molecular weight.First of all,Pd@Au nanoparticles with high photothermal conversion efficiency were synthesized by oxidation-reduction reaction.Subsequently,the CCRF-CEM specific aptamer Cy5-Sgc8c was modified by "Au-S" chemical bonds to Pd@Au nanoparticles developed a nucleic acid aptamers functionalized Pd@Au nanoparticles for targeted therapy of tumors.The experimental results showed that the functionalized Pd@Au nanoparticles had excellent photothermal conversion efficiency.After irradiated by 780 nm laser for 10 min,the Pd@Au@Cy5-Sgc8c nanoprobe had excellent killing effect on the target tumor cells,while the control groups had no obvious cell death.In summary,the nucleic acid aptamer functionalized Pd@Au nanoparticles have excellent targeting,good biocompatibility,high light and heat conversion efficiency advantages,which were expected to widely applied in the tumor diagnosis and treatment system.