【作者】 陈瑞；

【导师】 蒋锡群；

【作者基本信息】 南京大学 ， 高分子化学与物理， 2013， 博士

【摘要】 近年来随着肿瘤发病率的不断上升,发展新型的肿瘤治疗方法具有重要的意义。传统的治疗手段有手术、放疗、化疗等,发展中的新型治疗方法有热疗、光动力疗法、免疫疗法等。虽然这些治疗手段在目前的肿瘤治疗上发挥了重要的作用,但仍存在自身的弊端和无法完全抑制肿瘤的缺点,因此发展两种或多种肿瘤治疗手段联合起来共同抗击肿瘤,成为肿瘤医学研究的热点。联合治疗的研究除了临床实践的经验积累,还依赖于医学材料的多功能性的设计,来满足各种联合治疗的不同需求。随着纳米科学的发展,纳米技术越来越多地应用到生物医学领域。金纳米棒拥有表面等离子体共振性质,有着特殊的辐射和非辐射特性,有望成为一种新型的纳米结构,广泛地应用于生物和生物医学领域,包括生物传感、生物医学成像、基因和药物输送、疾病检测、诊断和治疗。金纳米棒很容易被与其纵向等离子体共振吸收峰波长相近的近红外光的诱导产生热量,因此在肿瘤的光热治疗中具有特殊的优越性。因为近红外光的组织穿透能力强,采用近红外激光作为光源,能够诱导皮下深层组织的金纳米棒产生热量而升温,对皮下深层组织的癌细胞能同时起到成像诊断和光热治疗的双重作用。本论文利用具有良好生物相容性和可生物降解性的壳聚糖为基质材料,通过与金纳米棒的高效复合,制备了尺寸可控且稳定的复合纳米微球,发挥金棒的光热效应来抑制肿瘤。并且,纳米微球与化疗药物、光动力药物分别复合,进行了热疗/化疗、热疗/光动力疗法的联合治疗,考察了它们的协同效应以及在抗肿瘤方面的效果。对于光动力疗法而言,以过氧化氢分子为响应信号,进行肿瘤信号的化学发光成像和内源性的光动力激发,将医学诊断和治疗共同结合。具体工作内容如下：(1)水溶液中带有正电荷的低分子量水溶性壳聚糖与带有负电荷的乙二胺四乙酸(EDTA),在不良溶剂乙醇的辅助下发生静电络合,形成纳米微球的同时高效地对金纳米棒进行包裹复合,制备了壳聚糖-金纳米棒(CS-AuNR)复合纳米微球。抗肿瘤药物顺铂被负载在纳米微球的壳聚糖壳体空间当中,形成多功能的壳聚糖-金纳米棒-顺铂(CS-AuNR-Pt)复合纳米微球。我们重点关注了金棒的光热效应和顺铂药物的协同作用,并由此带来的增强的抗肿瘤效果。这种复合微球提供了一种用多功能纳米载体作为热疗和化学疗法结合治疗的途径。(2)在制备的CS-AuNR复合纳米微球的基础上,光动力药物吲哚菁绿利用静电吸附作用,被复合在壳聚糖微球的壳体空间当中,形成壳聚糖-金纳米棒-吲哚菁绿(CS-AuNR-ICG)复合纳米微球。我们研究了壳聚糖微球对吲哚菁绿分子的水解保护作用以及微球的增强渗透治疗效应(EPR效应)对体内分布的影响,重点关注了金棒的光热效应和吲哚菁绿的光动力效果,以及它们的协同作用。这种多功能材料提供了一种被单一近红外光激发,同时触发光热/光动力双重治疗模式的途径。(3)利用两亲性的嵌段共聚物同时包裹过氧草酸酯低聚物、荧光染料和光动力药物,制备多功能纳米胶束进行低浓度过氧化氢的成像检测。胶束一方面可以保护过氧草酸酯低聚物避免与水直接接触而延迟水解,另一方面草酸酯和过氧化氢反应的能量可以有效地转移到相邻的荧光染料上,然后染料释放光能用于光动力治疗,将肿瘤的诊断和治疗结合。采用内源性的化学发光来激发光动力治疗,不论肿瘤是深入的还是靠近皮肤的,都可以采用此法进行光动力治疗,提供了一个解决光动力治疗不能深入体表的方案。更多还原

【Abstract】 In recent years, with the rising incidence of cancer, the development of new cancer treatment method has important significance. Traditional treatment methods include surgery, radiotherapy and chemotherapy, while new treatment methods are hyperthermia, photodynamic therapy, immunotherapy and so on. These methods play an important role in tumor treatment, but there are still great challenges in tumor suppression. Therefore, the combination of two or more cancer treatment means to fight against cancer, become the hot issue in present research. Combination therapy based on the experience of clinical practice, is also dependent on the versatility of medical materials designed to meet the different needs of cancer treatments.With the development of nanoscience, nanotechnology has been increasingly applied in the field of biomedicine. Gold nanorods with surface plasmon resonance, and their special radiation and non-radiation characteristics, are expected to become a new type of nanomaterials for the applications in biological and biomedical fields, including biosensing, biomedical imaging, gene and drug transportation, disease detection, diagnosis and treatment. Gold nanorods are easily induced to general hyperthermia by the near-infrared light close to the wavelength of its longitudinal plasma resonance absorption peak, so they have special advantages on the thermal therapy of tumor. Because near-infrared light has capability of deep tissue penetration, near-infrared laser as a light source can heat up the gold nanorods in deep subcutaneous tissue. Therefore, gold nanorods have been demonstrated to be promising in diagnosis and photothermal treatment of cancer cells in the deep subcutaneous tissue.In this work, we prepared size controllable and stable hybrid nanospheres by using chitosan as matrix material to complex gold nanorods. Combined with chemotherapy drugs and photodynamic drug respectively, the combination therapy of thermal therapy/chemotherapy or thermal therapy/photodynamic therapy is established to examine the synergic effect of them and their anti-tumor effect. For the photodynamic therapy, the therapeutic agents can be endogenously stimulated by chemluminescence of tumor imaging through hydrogen peroxide, a signal molecule of tumors, in which the medical diagnosis and treatment are combined together. Specific work contents are as follows:(1) In the aqueous solution, chitosan with low molecular weight is water-soluble and positive charged, while ethylenediamine tetraacetic acid (EDTA) is negatively charged. With the aid of the poor solvent of ethanol, they can efficiently package and complex gold nanorods to form the chitosan-gold nanorods (CS-AuNR) hybrid nanospheres through electrostatic complexation. Antitumor drug cisplatin is loaded on the shell matrix of chitosan to afford multi-function chitosan-gold nanorods-cisplatin (CS-AuNR-Pt) hybrid nanospheres. We focus on the synergic effect of gold nanorods and cisplatin, and their antitumor effects. This work provides a multifunction nanospheres carrier for combination of thermotherapy and chemotherapy treatment.(2) Photodynamic drugs, indocyanine green, is loaded on the shell matrix of the CS-AuNR hybrid nanospheres through electrostatic adsorption, to form chitosan-gold nanorods-indocyanine green (CS-AuNR-ICG) hybrid nanospheres. Protective effect of chitosan nanospheres on indocyanine green molecules against hydrolysis and the body distribution of the CS-AuNR-ICG hybrid nanospheres are investigated. We focus on the synergic effect of gold nanorods and indocyanine green. This multifunctional material provides a model that has the functions of thermo/photodynamic therapy triggered by single near-infrared light radiation.(3) With peroxide oxalate ester, fluorescent dyes and photodynamic drug encapsuled in the micelles prepared from an amphiphilic block copolymer, multifunctional nanomicelles are prepared for imaging hydrogen peroxide. On one hand, nanomicelles can protect the peroxide oxalate ester from hydrolysis; on the other hand, the reaction energy of peroxide oxalate ester with hydrogen peroxide can be effectively transferred to adjacent fluorescent dye. The excited dye release chemiluminescence for photodynamic treatment, combining the diagnosis and therapy of tumor. Since the photodynamic therapy can be inspired by endogenous chemiluminescence, tumor treatment can be achieved regardless of depth of the tumor. This provides a solution to the problem of photodynamic therapy which cannot treat deep tumor in the body.更多还原