【作者】 曹众；

【导师】 戴志飞；

【作者基本信息】 哈尔滨工业大学 ， 生物医学仪器与工程， 2011， 博士

【摘要】 恶性肿瘤是严重危害人类健康的疾病之一,化疗是目前必不可少的治疗方法。但目前的化疗药物不具有靶向性,不仅对癌细胞有杀伤性,对正常细胞同样具有杀伤作用,从而引起严重的毒副作用,阻碍了它们的发展和应用。脂质体作为诊断和治疗药物的载体已经得到越来越广泛的关注。尤其是脂质体已经被用来包裹各种亲水的和疏水的抗癌药物。但是脂质体最大的缺点是化学和物理的不稳定性,脂质体囊泡容易破裂,其内容物抗癌药物在到达肿瘤部位之前过早地泄漏,达不到缓释的效果,严重影响了它们在临床上的应用。为了克服上述问题,科学家们发展了一种长循环的脂质体—聚乙二醇化的脂质体。聚乙二醇化的脂质体似乎降低了内容物释放所引起的毒性作用,但不幸的是,因为聚乙二醇的存在产生了新的毒害作用。例如,含有聚乙二醇磷脂的脂质体药剂导致一种称为―手足综合症‖的皮肤毒性,这样会导致手心和脚底的皮疹和溃疡。因此很多业内人士认为,研制更稳定、肿瘤靶向性更好的脂质体是今后脂质体技术的发展方向。针对脂质体稳定性和缓释性欠佳等缺点,研发了一种具有超高稳定性的被称为―硅质体‖的新型有机-无机复合脂质体作为药物载体,这样可以克服当前脂质体技术的一般性问题。首先我们成功合成了这种有机-无机复合脂质分子,然后制备了硅质体并研究了它的制备工艺。硅质体是一种仿生胶体粒子,它具有类似脂质体膜的内水相,但是它的表面覆盖了一层无机的硅酸盐壳层。硅酸盐表面不仅保护了内层的脂质双层,而且它很容易连接生物活性分子。与传统的常规脂质体相比,硅质体表面的硅氧烷网络显著增加了脂质体的稳定性,对表面活性剂、酸碱都有很好的稳定性。由于硅质体囊泡在包封各种药物,包括亲水、疏水及两亲的药物方面具有潜在应用价值,因而它具有重要的意义。本研究选用了两种代表性抗癌药物:疏水性药物紫杉醇和亲水性药物盐酸阿霉素,它们分别被包裹进硅质体里面制成紫杉醇和盐酸阿霉素硅质体药物。优化了制备方法和工艺,制得的紫杉醇和盐酸阿霉素硅质体粒度分布均匀、分散性好,平均粒径约为150nm左右,能够满足临床上纳米药物载体对尺寸的要求。两种硅质体药物均具有很好的化学稳定性和贮存稳定性。体外释放实验表明,它们能够持续释放药物,达到很好的缓释效果,细胞实验也进一步证明了该结果。随后制备了掺杂磷脂(二硬脂酰磷脂酰胆碱)的紫杉醇硅质体,利用各种表征手段表征了掺杂磷脂的混合硅质体囊泡。证明了它们的混合方式是有机-无机复合脂质和磷脂是混合在一个囊泡里,而不是单独形成各自的囊泡。通过在硅质体中以不同比例掺入磷脂,可以控制药物的体外释放性能。为了达到靶向性,我们将磁性纳米粒子和抗癌药物盐酸阿霉素同时包裹在硅质体中制备了磁性盐酸阿霉素硅质体。利用激光红聚焦显微镜和流式细胞仪定性和定量的表征了HeLa细胞对磁性硅质体的摄取。实验结果表明:在施加磁场的情况下,该磁性硅质体能向癌细胞靶向地传递和释放药物,而且集稳定性、缓释性和靶向性于一体。本论文成功地制备了四种超稳定的新型硅质体药物,紫杉醇硅质体、紫杉醇混合硅质体、阿霉素硅质体、磁性阿霉素硅质体。硅质体是目前报道的具有超高稳定性的双层膜结构,从而使得这种人造细胞膜在生物医药领域具有很好的应用前景。硅质体作为药物载体在癌症治疗方面存在潜在的巨大应用价值,未来经济效益巨大。更多还原

【Abstract】 Malignant tumor is one of the most refractory disease risks for human health, chemotherapy drugs is absolutely necessarily therapeutic method. Most commonly used anticancer drugs are not specifically toxic to tumor cells and are toxic to all tissues they contact so they create undesirable side effects as a result of their interactions with normal tissues. These toxic side effects hinder their development and applications. Liposomes have received increasing attention as possible carriers for diagnostic or therapeutic agents. Especially, liposomes have been used to formulate a variety of hydrophilic and hydrophobic, poorly soluble drugs. Thus, liposomes are unstable to the circulation environment and/or its content will leak the antineoplastic agent prematurely before reaching the tumor site. The insufficient stability of liposomes may limit their applications. To overcome these problems, scientists have developed long-circulating liposomes—pegylated liposomes. The pegylated liposomes appeared to reduce some of the toxic effects caused by the release of their contents, but, unfortunately, new toxic effects appeared because of the presence of the polyethylene glycol. For example, the liposomal preparations containing pegylated phospholipids have lead to skin toxicity generally known as "Hand-Foot syndrome," which results in skin eruptions/ulcers on the palms of the hands and soles of the feet. So many scientists consider: preparing more stable and tumor-targing liposomes will be the development direction of liposome technique in the future.To overcome these problems, recently, a novel super-stable and freestanding hybrid liposomal cerasome （partially ceramic- or silica-coated liposome） was fabricated using self-assembly and a sol–gel strategy to overcome general problems associated with current liposome technology. First, we successfully synthesized the cerasome-forming lipid. Then we prepared cerasomes and studied the optimal preparation technics. Cerasome is a bioinspired colloidal particle having an inner aqueous compartment like the liposomal membrane but its surface is covered with the inorganic silica framework. In addition, the nontoxic silica surface protects the inner lipid bilayer and is amenable for bioconjugation with silane-coupler chemistry. This biomimetic material is remarkably high stability towards surfactant solubilization, and acidic treatment, compared with conventional liposomes. Therefore, cerasome vesicles are of major importance due to their potential applications for the encapsulation of a variety of guest species including hydrophilic, hydrophobic and amphiphilic molecules.The current study demonstrates for the first time that hybrid liposomal cerasomes can be used as a new promising drug delivery system. A lipophilic anticancer drug paclitaxel （PTX） and a hydrophilic anticancer drug doxorubicin （DOX） were used as test drugs and loaded in cerasmes to prepare PTX-loaded cerasomes （PLCs） and DOX-loaded cerasomes （DLCs）. We studied the optimal preparation technics to obtain PLCs and DLCs with uniformity paticle size of 150nm and non-aggregated vesicles. The two cerasome pharmaceuticals are with high morphological stability and storage stability with good biocompatability. In vitro release of drugs experiments indicated cerasomes can release the drug for a sustained period of time. Later, the "mixed" cerasomes were fabricated from mixtures of the cerasome-forming lipid and phospholipids. The―mixed‖cerasomes were characterized various methods. These results strongly indicated that cerasome-forming lipid and DSPC were both incorporated in one vesicle, not macroscopically phase-separated to form separate vesicles of each lipid component alone. It also provided us an ability to modulate the release rates of encapsulated drugs by altering the ratios of the cerasome-forming lipid and phospholipids. We prepared magnetic cerasomes composed of doxorubicin （DOX） and superparamagnetic iron oxide （Fe₃O₄）. To study the cell uptake, the NBD-labeled magnetic fluorescence cerasomes （MFCs） were prepared and was characterized by confocal laser scanning microscopy and flow cytometer. These results indicated that magnetic DOX-loaded cerasomes （MDCs） are a promising candidate for treating cancer and monitoring the progress of the targeted cancer therapy with stability, sustained release and targeted ability.This paper successfully prepared four super stable cerasome pharmaceutics, PLCs, DLCs, PTX loaded mixed cerasomes and MDCs. Cerasome is the high stable lipid bilayer, so that this artificial cell membrane has beautiful applications prospects for the biology medicine field. Cerasome vesicles as drug carrier have their potential applications for cancer therapy and will bring large economic benefits.更多还原