【作者】 郭伟；

【导师】 刘绍琴； 果崇申；

【作者基本信息】 哈尔滨工业大学 ， 生物医学工程， 2018， 博士

【摘要】 作为全球第二大致死病因,癌症已经严重威胁了人类的健康与生命,但传统的手术治疗、化疗等往往存在手术面积大、副作用大等缺点。光热治疗（PTT）和光动力治疗（PDT）分别利用光活性物质的光热效果与光生活性氧物质诱导肿瘤细胞凋亡或消融肿瘤组织,具有毒性低、副作用小、治疗时间短、可重复治疗的优点,为癌症的诊断与治疗提供了新的途径。目前,PDT面临的困难是治疗过程中肿瘤组织中氧的快速消耗会降低其效果,而PTT效果会随着光照时间的增加而由弱变强,因此将PDT与PTT相结合具有较好的协同作用。此外,如何实现对癌症的精准诊疗一直是医学界的难题和研究热点,而基于影像介导、多模式肿瘤治疗的诊疗一体化手段,能够在治疗过程中有效评估肿瘤的最佳治疗时间窗并随时调整治疗方案,有利于达到最佳治疗效果和较少治疗的副作用,有望成为个性化医疗/精准医疗的一种新策略。目前构筑诊疗一体化材料的方式主要是将多种组分简单组合在一起,该方法获得的材料存在组分间相互干扰、合成复杂、使用过程中容易解体等缺点。针对以上的诸多问题,本论文设计合成了铯钨青铜纳米粒子,进而针对其与细胞、肿瘤组织界面的相互作用,对其表面进行生物功能化修饰,利用其光动力效应、光热转化能力以及高原子序数特征,构建了三种多模式诊疗材料体系,实现癌症多功能成像与光治疗的一体化。具体研究内容如下:采用“控制缓释水”的溶剂热方法制备了铯钨青铜纳米粒子,系统地探究了溶剂组成、反应温度、反应介质的种类、铯与钨投料摩尔比以及水的引入方式等合成条件对铯钨青铜粒子微观结构以及光学性质的影响,并通过紫外-可见-近红外吸收光谱、透射电镜以及X射线衍射等表征手段确定铯钨青铜纳米粒子的最优合成条件,获得了尺寸适中、近红外吸收强、光热与光动力效应显著的铯钨青铜纳米粒子,为后续多功能诊疗体系的构建提供了基础。针对铯钨青铜纳米粒子在生理及类生理条件下分散稳定性差的问题,采用静电层层自组装的方法分别将带正电的聚烯丙基胺盐酸盐与带负电的聚（4-苯乙烯磺酸钠）交替修饰于铯钨青铜粒子表面,成功地制备了聚电解质修饰的铯钨青铜纳米粒子（M-Cs_xWO₃）。体内外光声成像与CT成像结果表明M-Cs_xWO₃具有良好的光声与CT成像效果。同时,M-Cs_xWO₃可使用“第一生物窗口”与“第二生物窗口”的激光进行光热与光动力协同治疗,实现了集肿瘤双模式成像、双光区响应、双重光治疗效果于一体的诊疗一体化研究。针对肿瘤缺氧环境所造成的光动力疗效下降的问题,使用对生物无毒且可携带氧的全氟-15-冠-5-醚（PFC）对铯钨青铜进行包裹,获得的PFC包裹的铯钨青铜纳米粒子（Cs_xWO₃@PFC）,具有增强的光动力治疗效果。通过对比Cs_xWO₃@PFC对缺氧条件下培养的胰腺癌细胞（PANC-1-H）以及常氧条件下培养的胰腺癌细胞（Bx PC-3/PANC-1）的光治疗效果证明了Cs_xWO₃@PFC具有增强的光动力治疗效果。此部分研究对于高耐药性与低治愈率的缺氧条件下培养的胰腺（PANC-1-H）肿瘤的治疗获得了积极的实验结果。此外,Cs_xWO₃@PFC具有预期的光声和CT成像能力。为了解决铯钨青铜纳米粒子对肿瘤无主动靶向能力的问题,将CRGDK修饰于铯钨青铜表面,获得具有靶向的Cs_xWO₃@CRGDK纳米诊疗剂,其可以实现对乳腺癌细胞的主动靶向。此外,针对单色激光用于光治疗过程中肿瘤组织易产生适应性的问题,首次使用波长分布于800-1300 nm的近红外光源进行光热/光动力治疗。结果表明在相同的功率密度下,近红外光的治疗效果要优于波长为880 nm与1064 nm的单色激光。同时,在荧光成像、光声成像以及CT成像的引导下,实现了乳腺癌在近红外光照射下的光热/光动力协同治疗。更多还原

【Abstract】 Being the second leading cause of death in the world,cancer has already threatened the lives and health of human beings seriously.However,the tranditional treatments like surgical treatment and chemotherap y,often suffer the disadvantages of large surgical area and side effects etc.Photothermal therapy（PTT）and photodynamic therapy（PDT）rely on photothermal effect of photoactive substances and photo-induced reactive oxygen species,to induce tumor cell apoptosis or ablate cancer tissues,respectively.Compared to tranditional treatments,PTT and PDT exhibit favorable characteristics such as low side effects,short time and repeatable therapy,thus providing an effective approach for cancer therapy.However,PDT effect decreases over time due to the depletion of tissue oxygen,while the PTT effect gradually increases upon irradiation,thus combining PDT and PTT would produce a synergistic effect.Moreover,how to realize the precision diagnosis and therapy of cancer is a crucial problem.One effective way is developing cancer theranostic platform by introducing imaging during multi-modal therapy process,which can realize real-time monitoring during the treatment,improve the accuracy of cancer treatment and decrease the side effects.To date,most theranostic systems have been constructed by integrating multiple components with different functions（imaging or therapy）in a complex system.However,simple combination of different materials often results in a series of shortcomings such as mutual interference between ingredients,easy collapse of the complex systems in vivo and complicated operation.To overcome above problems,in this thesis,Cs_xWO₃ nanoparticles have been synthesized and functionalized with bioactive component according to their interaction with cells and tumor tissues.The functionalized Cs_xWO₃ nanoparticles exhibited high photodynamic effect,photothermal conversion efficiency and high atomic number,thus can be used as multifunctional theranosic agent,for multifunctional imaging and photothermal/photodynamic synergistic therapy.The specific research contents are as follows:Cs_xWO₃ nanoparticles were prepared by solval thermal approach.The influence of synthetic conditions on the nanostructure and optical properties of Cs_xWO₃particles were investigated firstly,including the composition of solvent,the reaction temperature,the type of reaction medium,the molar ratio of cesium to tungsten and the way of water introduction.The optimum synthetic conditions of Cs_xWO₃nanoparticles were determined by UV-vis-NIR absorption spectra,transmission electron microscope and X-ray diffraction.Finally,the optimized Cs_xWO₃nanoparticles with suitable size,strong near infrared absorption and significant PTT and PDT effects were obtained,which provided the basis for the construction of the multi-functional theranostic systems in the following chapters.To solve the problem of poor dispersion stability of bare Cs_xWO₃ under physiological and simulated physiological conditions,the positively charged poly（allylamine hydrochloride）and negtively chargedpoly（sodium 4-styrenesulfonate）were alternately modified on the surface of Cs_xWO₃ nanoparticles by an electrostatic interaction mediated layer-by-layer method.As a result,the polyelectrolyte modified Cs_xWO₃ nanoparticles（M-Cs_xWO₃）were successfully prepared.Both of in vivo and in vitro tests manifested great potential of Cs_xWO₃ NPs for cancer photoacoustic and CT imaging.Meanwhile,the M-Cs_xWO₃ NPs are qualified for photothermal and photodynamic synergistic therapy in both"first biological window"and"second biological window",respectively.Given the above,this part of content achieved the combination of cancer diagnosis and treatment in single M-Cs_xWO₃,which realized tumor dual-mode imaging,dual-spectral response and dual-phototherapeutic modalities.To overcome the deterioration of photodynamic efficacy caused by tumor hypoxic environment,the Cs_xWO₃ nanoparticles were encapsulated with perfluoro-15-crown-5-ether（PFC）,which is a nontoxic dissolved-oxygen carrier,to achieve the improved the PDT effect.Comparative trials between therapeutic effects of PFC encapsulated Cs_xWO₃ nanoparticles（Cs_xWO₃@PFC）on chemically induced hypoxic pancreatic cancer cells（PANC-1-H）and normoxic pancreatic cancer cells（Bx PC-3/PANC-1）has been proved that the Cs_xWO₃@PFC possessed improved PDT effect due to the oxygen on-demand supplement.This part of the study evidenced positive results for the treatment of pancreatic cancer（PANC-1-H）,which is typically as hypoxic and drug resistant properties.In addition,Cs_xWO₃@PFC also has the expected photoacoustic and CT imaging capabilities.To improve active targeting abilities of Cs_xWO₃ nanoparticles toward the tumors,the CRGDK peptide was modified on the surface of Cs_xWO₃ to obtain targeted Cs_xWO₃@CRGDK nano-theranostic agent,which could actively target to MDA-MB-231 cancer cells.In addition,a NIR light source with continuous wavelength of 800-1300 nm was used for photothermal/photodynamic therapy for the first time,aiming to overcome the adaptability of tumor tissue during phototherapy to a single wavelength laser.These results showed that the therapeutic effect of NIR mediated group was much better than that of single wavelength of 880 nm or 1064 nm under the same power density.The photothermal/photodynamic synergistic therapy on triple-negative breast cancer was realized by NIR,as well as realizing triple-surveillance of fluorescence imaging,photoacoustic imaging and CT imaging.更多还原