Preparation Of Polydopamine Composite Nanomaterials And Its Application In Drug Delivery And Photothermal Therapy

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents.Patients with localized osteosarcoma were treated with surgical excision and chemotherapy to improve survival.However,non-specific distribution,long-time toxic side effects,and adverse effects on normal tissues and organs limit the application of chemotherapy drugs.With the development of nanotechnology,the nano-delivery systems can improve the utilization rate of drugs,extend the half-life of circulation,and reduce the toxic and side effects on normal tissues.Photothermal therapy has attracted wide attention due to its less invasive nature,fewer complications and rapid recovery.The combination of photothermal therapy and nano-drug deliver can effectively improve the therapeutict of bone tumors.In this study,mesoporous polydopamine nanoparticles loaded with curcumin and 2,2’-azobis[2_{2-imidazolin-2-yl}propane]-dihydrochloride were prepared to explore their applications in photothermal therapy and temperature response drug release.The main contents were as follows:（1）In this study,polydopamine nanoparticles were used as photothermal agents.First,poly dopamine nanoparticles and Pluronic F127 stabilized emulsion were assembled on water/1,3,5-trimethylbenzene interface to obtaine mesoporous polydopamine Nanoparticles.The phase change material lauric acid as the drug loading medium loaded the curcumin into the pores of the mesoporous polydopamine nanoparticles.Mesoporous polydopamine nanoparticles act as photothermal agents,which can increased the temperature by near-infrared laser irradiation,and then release curcumin when it changes from solid to liquid above the melting point of lauric acid.The introduction of mesoporous polydopamine can increase the drug loading efficiency,and its photothermal properties can increase the therapeutic effect of cancer.Cell experiments have shown that the compositematerial could reduce mitochondrial membrane potential through photothermal therapy,and the released curcumin can produce reactive oxygen species,inhibit the proliferation of MG63 cells and induce their apoptosis.The composite nanomaterials prepared in this study have the synergistic effect of chemotherapy and photothermal therapy,which greatly improves the therapeutic effect of osteosarcoma.（2）The 2,2’-azobis[2-（2-imidazolin-2-yl）propane]-dihydrochloride loaded on mesoporous polydopamine nanoparticles,and then coated with bovine serum albumin to prevent the drug from being released prematurely.We developed and prepared a multifunctional nanomaterial with photothermal therapy,drug delivery and free radical generation.By irradiate mesoporous polydopamine nanoparticles with near-infrared lasers converts light energy into heat energy,causing the decomposition of 2,2’-azobis[2-（2-imidazolin-2-yl）propane]-dihydrochloride and achieve control the release of free radicals.Cytological experiments have shown that the composite nanomaterials can induce cancer cell apoptosis,effectively improve cancer treatment effects,and have great potential in the clinical application of future tumor treatment.