Polydopamine-coated Fe₃O₄/Drugs Composite Superparticles For Magnetic Targeting And Treatment Application

As two fatal diseases,pulmonary fibrosis and ovarian cancer need specific drugs to treat them.In the process of traditional treatment,the systemic toxic and side effects caused by the non-specific targeting of drugs have brought great trouble to the health and clinical treatment of patients.Therefore,in recent years,the realization of accurate targeted drug delivery has become the focus of researchers.Among them,the functional elements of nanocomposites are diverse,and they have great application potential in the drug targeted delivery,which has attracted extensive attention of researchers.Fe₃O₄ nanoparticles have superparamagnetism and can aggregate at specific sites under the action of the external magnetic field to achieve accurate targeted drug delivery.As a biocompatible polymer,polydopamine has mussel-like viscosity and easy modification can load most drugs.The degradability of polydopamine in the human body can realize the release of drugs at the focus.In this paper,we used the self-assembly of Fe₃O₄nanoparticles to construct Fe₃O₄superparticles,and coated the drug loaded polydopamine shell on the surface of the superparticles.Magnetic targeting is realized by the strong magnetism of Fe₃O₄ superparticles,and the drug delivery and treatment of diseases are realized by the loading and release of drugs in polydopamine shell.In Chapter 2,we successfully prepared the polydopamine coated Fe₃O₄/cyc lophosphamide/methylprednisolone composite superparticles（Fe₃O₄/CTX/MPS@PDA SPs）by using Fe₃O₄ superparticles as structural units,coating the su rface of the superparticles with polydopamine shell and loading the drugs（cyclophosphamide and methylprednisolone）for the treatment of pulmonary fi brosis.The composite superparticles can effectively release the two drugs w hen simulating the lung environment in vitro.In the wearable magnetic targ eting model of mice,it can effectively enrich the lung,showing the potentia l for the treatment of pulmonary fibrosis.In Chapter 3,we also used Fe₃O₄ superparticles as structural units,coated the surface of the superparticles with polydopamine shell,loaded the chemotherapy drug vincristine,and successfully prepared polydopamine coated Fe₃O₄/vincristine composite superparticles（Fe3O4/VCR@PDA SPs）.The composite superparticles can be highly enriched in the tumor site under the action of magnetic targeting,and responsively release the chemotherapy drug vincristine which is in the shell in the tumor microenvironment to realize the chemotherapy of the tumor.Further application of 808 nm near-infrared laser,the synergistic effect of chemotherapy and photothermal therapy can effectively achieve the treatment of ovarian cancer.