Controlled Synthesis And Application Of Hollow Copper Sulfide Nanoparticles And Nanocomposites

With the development of nanotechnology,the nano-science and biological technology shows a great potential application in biological science such as drug delivery,biological sensors,imaging and photothermal therapy.Compared with noble metal materials,copper sulfide nanomaterials have tremendous value of research for actual application due to its low cost,low cytotoxicity,and intrinsic NIR region absorption which rarely affected by its surrounding and size.In this paper,hollow copper sulfide nanostructures and its nanocomposites were successfully prepared,and their applications in the fields such as cancer treatment and biological catalysis were also studied,respectively.The main content can be summarized as follow:Chapter 1.The research progress and applications on the nanomaterials were demonstrated.And the topic ideas and significance of the dissertation were discussed.Chapter 2.Hollow copper sulfide nanoparticles were synthesized successfully by sacrificial template method.The intrinsic peroxidase-like activity of the obtained CuS nanoparticles were testified by using the oxidizing reaction of 3,3',5,5'-tetramethylbenzidine(TMB).And the kinetic and catalytic mechanism were researched in detail.On the basic of its peroxidase-like activity,CuS nanoparticles can be used as biosenser for detection of glucose or cleaner for degradation of methylene blue.Chapter 3.CuS@PPy nanocomposites were prepared by coating polypyrrole(PPy)on the surface of hollow CuS nanoparticles.The peroxidase-like activity,kinetic and catalytic mechanism of the obtained CuS@PPy nanocomposites were also researched.Compared with hollow CuS nanoparticles,CuS@PPy nanocomposites showed better catalytic activity.Using nanocomposites as catalyst to detect glucose,the detection limit was 0.625 ?M,which was much lower than that of hollow CuS nanoparticles.And the degradation of methylene blue can be realized at room temperature,which indicate that it has extensive application in catalysis.Chapter 4.Based on the good peroxidase-like activity and NIR absorption of CuS nanoparticles,the application of CuS@PDA nanocomposites on multi-functional and synergetic therapy was researched.First,hollow CuS nanoparticles were modified with polydapamine(PDA)nanolayers.Then CuS@PDA-FA nanocomposites were obtained by coupling with folic acid(FA),which was used as targeting molecule.The experiments data showed that the biocompatibility and the peroxidase-like activity of the nanocomposites was improved by modifying PDA shell.Besides,CuS@PDA,as a mimics of peroxidase,can catalyze H2O2 to produce hydroxyl radical with strong oxidizability.Thus,the reactive-oxygen species(ROS)concentration was improved in cancer cells in the presence of CuS@PDA-FA nanocomposites and ascorbic acid,which will cause toxic effects to tumor.Therefore,based on the properties of CuS@PDA-FA nanocomposites,the combination of ROS-mediated therapy,chemotherapy and phototherapy can be realized.Otherwise by using the targeting function and peroxidase-like activity of CuS@PDA--FA nanoparticles,a simple colorimetric assay system to diagnose cells number of human cancer was developed.