【作者】 查正宝；

【导师】 戴志飞；

【作者基本信息】 哈尔滨工业大学 ， 生物医学工程， 2013， 博士

【摘要】 光热治疗是近年来发展的一种微创肿瘤治疗技术，通过激光将肿瘤局部温度升高来杀死肿瘤细胞，能够实现定点杀伤，大大降低了全身系统毒性，因此光热治疗被看作是非常有潜力替代手术的治疗肿瘤的技术之一。然而，有效的光热治疗一般需要光热治疗剂的辅助。目前的无机光热治疗剂具有较高的光热转换效率，但是由于表面修饰困难，导致其靶向性差、携载药物困难，同时无机光热治疗剂的不可降解性也令人担忧；有机光热治疗剂一般具有良好的生物相容性，但是其较低的光热转换效率及光热稳定性、复杂的合成方法限制了其进一步应用。此外，成功的光热治疗还需要借助于合适的成像技术。所以开发具有成像功能、高靶向性和载药能力、高的光热转换效率和光热稳定性、制备方法简单的新型光热治疗剂具有重要的研究意义。针对目前硫化铜纳米粒子光热治疗剂靶向性差、携载药物困难等问题，本研究通过将硫化铜纳米粒子与微泡超声造影剂结合，实现了在超声诊断辅助下的靶向递送硫化铜纳米粒子至肿瘤部位进行有效的肿瘤光热治疗，大大提高了光热治疗的精准度与疗效。进一步根据肿瘤部位含有大量的明胶水解酶的特性，通过高碘酸盐氧化法合成了键连有化疗药物阿霉素的明胶-阿霉素共聚物，并将其作为稳定剂制备了集酶响应药物释放、光声成像与光热治疗于一体的酶响应硫化铜纳米粒子，实现了光热治疗与化疗对肿瘤组织的协同治疗，大大提高了治疗效果。为了避免无机光热治疗剂在体内长期存留所引起的潜在毒性，本研究开发了生物相容的有机聚吡咯纳米粒子作为新型具有光声成像功能的光热治疗剂。通过一步液相分散聚合法制备了形貌均一，平均粒径为~46nm的聚吡咯纳米粒子。聚吡咯纳米粒子在水溶液及生物介质中具有优良的分散性能及稳定性，与传统的光热治疗剂金纳米棒相比，具有更高的光热转换效率及光热稳定性。由于其显著的近红外光吸收特性，聚吡咯纳米粒子能够很好地对深部组织进行光声成像，体外光声成像深度达到了4.3cm，并且体内外肿瘤的光热消融实验证实了聚吡咯纳米粒子用于肿瘤光热治疗的巨大潜力。由于有机聚吡咯材料的溶解性极差，严重限制了聚吡咯材料的进一步加工应用。为了克服这一缺陷，本研究合成了可溶性的聚吡咯复合物，并通过简单的水包油乳液法制备了包裹有液态氟碳的聚吡咯微/纳米胶囊。其内部包裹的液态氟碳能够显著增强体内外超声回声信号，而聚吡咯壳层则保证了其优良的光热转换性能。制备得到的聚吡咯微/纳米胶囊在水溶液及生物介质中具有良好的分散性及升温性能，体内外的肿瘤光热消融实验证实了包裹有液态氟碳的聚吡咯微/纳米胶囊是一种新型的具有超声成像功能的多功能光热治疗剂，在肿瘤的光热治疗方面具有很大的潜力。针对简单功能模块组合得到的多功能光热治疗剂可能会增加患者在治疗时使用的药物剂量，从而加重了患者的代谢负担及潜在的全身毒副作用。本研究利用可溶性有机聚吡咯复合物与聚乙烯吡咯烷酮高分子之间的π-π共轭作用，通过一步水包油微乳液法制备了组成单一，具有超声成像功能的多功能聚吡咯空心微球光热治疗剂。聚吡咯空心微球在水溶液及生物介质中具有良好的分散性，内部的空腔使得其具有良好的超声造影增强的能力。体内外的肿瘤光热消融实验证实了在近红外激光的照射下，聚吡咯空心微球能够有效的杀死肿瘤细胞，在超声成像监测下的肿瘤光热治疗方面具有非常广阔的应用前景。综上所述，本研究通过将无机光热治疗剂硫化铜纳米粒子与微泡超声造影剂结合，实现了超声成像及靶向递送硫化铜纳米粒子至肿瘤部位进行有效的光热治疗；进一步根据肿瘤部位高含量的明胶水解酶特性，成功制备了集酶响应释放药物、光声成像与光热治疗功能于一体的酶响应硫化铜纳米粒子，并实现了光热治疗与化疗的协同作用，提高了肿瘤治疗的疗效；为了避免无机光热治疗剂在体内长期存留引起的潜在毒性，论文开发了生物相容的有机聚吡咯纳米粒子作为具有高光热转换效率及光热稳定性的多功能光热治疗剂用于光声成像与肿瘤的光热治疗；通过合成可溶性的聚吡咯复合物克服了传统聚吡咯材料溶解性差的缺陷，成功制备了集超声诊断与光热治疗功能于一体的聚吡咯微/纳米胶囊及聚吡咯空心微球，在肿瘤的可视化治疗中具有非常好的应用前景。更多还原

【Abstract】 Photothermal therapy (PTT) has gained popularity as a promising minimallyinvasive alternative to surgery by delivering photoenergy directly into tumor tissueswithout causing systemic effects. However, PTT agents are required for realizingeffective PTT. Currently, inorganic PTT agents with high photothermal conversionefficiency, have difficulties in surface modification, targeting and carrying drugs.And their non-biodegradability is still worrying. Organic PTT agents have goodbiocompatibility but the low photo-thermal conversion efficiency, photothermalstability and complicated synthesis process limit their further use. On the other hand,appropriate imaging techniques are essential to realize successful PTT treatment.Thus, introducing imaging modalities to PTT agents with high targeting and drugloading ability, high photothermal conversion efficiency and photothermal stabilityas well as simple preparation method, is of great importance.CuS nanoparticles (NPs) have difficulties in targeting and drug loading. In thisstudy, a novel microbubble system was developed for both ultrasound imaging andtargeted CuS NPs delivery using ultrasound-targeted microbubble destruction to killtumor cells by PTT. Futhermore, multifunctional CuS NPs stabilized with DOX-conjugated gelatin (CuS@Gel/DOX NPs) were developed to combine thephotoacoustic tomography (PAT), enzyme-responsive drug delivery and PTT forcancer treatments. CuS@Gel/DOX NPs could selectively release drug due to theenzymatic degradation of gelatin-DOX conjugates. Moreover, a synergistic effect inkilling cancer cells was found by the combined photothermal therapy andchemotherapy with minimal side effects.In order to avoid the potential long-term toxicity of inorganic photothermalagents, uniform biocompatible polypyrrole (PPy) NPs with a average diameter of~46nm were constructed from a facile one-step aqueous dispersion polymerizationmethod. The as-prepared PPy NPs exhibited good colloidal stability, significantphotothermal conversion efficiency due to strong NIR absorption and goodphotostability, higher than the well known Au nanorods. Moreover, the strong NIRabsorption allowed visualization of PPy NPs-containing agar gel embeded in chickenbreast muscle at a depth of~4.3cm by PAT. Our results indicate that PPy NPs arepromising agents both for PAT and PTT, with good biocompatibility.To overcome the inferior solubility of polypyrrole materials in common solvents,soluble PPy complex were synthesized and used for developing PPymicro/nanocapsules with encapsulated perfluorooctylbromide (PPyPFOBMC/PPyPFOBNC) from a facile one-step emulsion method. Owing to the encapsulated liquid PFOB and strong NIR absorption of PPy shell, the resulted PPyPFOBMC/PPyPFOBNC not only provided excellent contrast enhancement for ultrasoundimaging, but also served as efficient photoabsorbers for NIR photothermal tumorablation using a rather lower laser power density at0.64W/cm2. In vitro and in vivostudies both showed no side effects of PPyPFOBMC/PPyPFOBNC was observed atour tested doses. Thus, this simple and highly efficient theranostic agent based onpolypyrrole-composites would remarkably improve the methodologies for cancerdiagnosis and therapy.Simple physical combination of different dianostic and therapeutic elementwould give a relatively high onetime dose which may cause systemic toxicity andimpose an extra burden for the patients to excrete the theranostic agents. Thus,organic polypyrrole hollow microspheres (PPyHM) with good dispersity weredeveloped for the first time as an photothermal agent with US-responsive capabilityvia a facile oil-in-water (O/W) micro-emulsion method by employing soluble PPycomplex. Due to the π-π interaction of PPy complex and polyvinylpyrrolidone, thegenerated PPyHM not only provided excellent contrast enhancement for ultrasoundimaging, but also served as efficient photoabsorbers for NIR photothermal tumorablation both in vitro and in vivo.In conclusion, novel microbubble with CuS NPs could be used for bothultrasound imaging and targeted CuS nanoparticles (NPs) delivery through UTMD tokill tumor cells by PTT; CuS@Gel/DOX NPs could selectively release drug due tothe enzymatic degradation of gelatin-DOX conjugates as well as strong NIRabsorption for PAT and PTT; Organic PPy NPs are promising agents both for PAT andPTT, with good biocompatibility; PPy composites fabricated from soluble PPycomplex not only provided excellent contrast enhancement for ultrasound imaging,but also served as efficient photoabsorbers for NIR photothermal tumor ablation bothin vitro and in vivo.更多还原