Hollow Nanostructured Materials And Their Biomedical Applications

Chemotherapy is a conventional approach for the treatment and curing of cancer in clinical practices. However, chemotherapy often destroys healthy cells and causes toxicity to the patient. These shortcomings will limit the chemotherapectic efficacy. Therefore, nano delivery systems have been developed to enhance drug activity and targeting by scientists. In consideration of the biological safety, the nanocarriers should have high drug loading capacity and excellent biocompatibility, not easily recognize and clearance by biological systems and induce undesired side effects by a nonspecific accumulation in vivo.Ini view of the above problems, this dissertation focuses on design and systhesis of a series of multifunctional nanocarriers for cancer therapy. The main contents are summarized as follows:Chapter 1 provides an overview about synthesis of hollow nanostructured materials and their applications in biomedicine. We introduce some typical hollow nanostructured materials as nanocarriers for cancer therapy. Consideration of the present nanocarriers’ shortcoming, we suggest a strategy of the combination of different treatments and improvement of the targeting effect of nanocarriers to improve the efficacy of cancer therapy, and show the objectives of this study.Chapter 2 shows a solid-liquid reaction between Cu2O nanocubes and thiourea to synthesize CuS nanocages. Duo to the hollow cavity of the nanostructures, the as-synthesized CuS nanocages display exceptionally high drug loading capacity of DOX and release of DOX is pH-controllable. While the hollow nanocages can be used to load anticancer drug for chemotherapy, the CuS can convert NIR light into heat for photothermal therapy. The chemotherapy and photothermal therapy can be successfully combined within CuS nanocages, which effectively improves the efficacy of cancer therapy.Chapter 3 introduces spindle-like Polypyrrole hollow nanocapsules with high biocompatibility, which fabricated via a nanotemplate-mediated approach. The hollowcavity of nanocapsules can be used to load the anticancer drug (i.e., doxorubicin) for chemotherapy. More importantly, the spindle-like Polypyrrole hollow nanocapsules can penetrate cells more rapidly and efficiently in comparison with the spherical Polypyrrole hollow nanocapsules. The Polypyrrole shells can convert NIR light into heat for photothermal therapy. Therefore, the chemotherapy and photothermal therapy can be successfully combined within Polypyrrole hollow nanocapsules, which effectively improves the efficacy of cancer therapy.Chapter 4 reports a facile and effective route for synthesis of yolk-shell structured Fe3O4@NiSiO3 magnetic nanocomposites. Each Fe3O4@NiSiO3 nanocomposite has a magnetic iron oxide core and a mesopores and hollow nickel silicate shell with high specific surface area, which can provide high densities of Ni2+ for selective binding and separation of His-tagged proteins from protein mixture. Because of the Fe3O4 cores, the separation, concentration, and recycling of the nanocomposites become feasible under the controls of magnets.Chapter 5 We rationally design and synthesize a dual-targeted multifunctional platform based on the yolk-shell nanostructured Fe3O4@MgSiO3 magnetic mesoporous nanocomposites, which composed by a magnetic core and a hollow and mesoporous magnesium silicate shell, and then the surface properties of the nanospheres were modified with biocompatible polymer poly(ethylene glycol) (PEG) and cancer-cell-specific ligand folic acid, with the aim of specifically targeting cancer cell. The nanocomposites displayed the excellently biocompatibility, which is in favor of further biological applications. Surface conjugation with cancer-specific targeting agent folic acid increased the uptake into multidrug resistant cells. In vivo experiments indicated that the as-synthesized presented the excellent targeted effect, which could be used as a novel platform for simultaneous imaging, therapeutic applications and overcoming multiple-drug resistance.Chapter 6 summarizes the study. We have synthesized several multifunctional hollow nanostructured materials, and proposed a novel strategy of the combination of different treatments and improvement of the targeting effect of nanocarriers to reach a high efficacy of cancer therapy. We belive these hollow nanostructured materialswould hold a promise for effective treatment of various cancers.