【作者】 张宇；

【导师】 杜健军；

【作者基本信息】 大连理工大学 ， 精细化工， 2020， 硕士

【摘要】 智能响应型药物递送系统(Smart Stimuli-Responsive Delivery),即负载着治疗药物的纳米载体在进入肿瘤组织后,在肿瘤微内部环境或某些外部特定刺激下释放药物以增强治疗效果。白蛋白因其优异的生物相容性、生物降解性、营养价值高和与多种药物的超强结合能力等优点,而在药物输送体系中被广泛研究。超声(Ultrasound)作为一种机械波,具有无创性、可控制性和高组织穿透能力等优点,因而在临床诊断中被广泛应用。因此,本文制备了一种超声可调控药物释放的牛血清白蛋白(BSA)纳米载体,并对其超声调控下深层组织中化疗药物(阿霉素)的释放进行了研究。(1)设计并制备了一种以BSA为骨架,超声可断裂的4,4’-偶氮(4-氰基戊酸)(ACVA)为交联剂,包载抗癌药物盐酸阿霉素(DOX)的纳米粒子BSA-ACVA-DOX。经透射电镜和动态光散射表征,制备的纳米粒子呈均匀分布的球形,粒径为171±2.8nm,Zeta电位为-19.8 mV;DOX载药率为6.8%,包封率为94.5%,在PBS缓冲溶液中具有良好的稳定性(7天内粒径和多分散系数无明显变化)。BSA-ACVA-DOX纳米粒子在30 min内可快速进入MCF-7细胞并定位于溶酶体,具有良好的生物相容性,在200mg/L浓度下孵育24 h后细胞存活率在80%以上。(2)使用1 MHz,2.0 W/cm~2作为安全的超声条件,且并不会对蛋白、核酸和酶等生物大分子活性造成影响。体外测试显示,BSA-ACVA-DOX纳米粒子的结构在超声刺激下被明显破坏。可通过外源超声“关-开”实现体内药物可控释放,30 s内释放即可达到16%,10 min可提升至74%。超声赋予体系具有良好的组织穿透能力,在1 cm组织厚度下在10 min内DOX释放率为45%,2 cm组织厚度下为32%。细胞毒性实验表明在超声3 min后可有效杀伤肿瘤细胞,细胞存活率仅为17%综上,白蛋白纳米粒子BSA-ACVA-DOX纳米粒子拥有良好的超声激活快速药物释放能力,具有高的生物安全性和组织渗透性,可实现在时空上对药物的可控释放,作为智能药物递送系统具有广阔的应用前景。更多还原

【Abstract】 Smart Stimuli-Responsive Delivery,that is,when nanocarriers loaded with therapeutic drugs enter the tumor tissue,can release the drugs for tumor treatment under the tumor micro-internal environment or certain external specific stimuli.Albumin has been widely studied in drug delivery systems due to its excellent biocompatibility,biodegradability,high nutritional value and binding ability with multiple drugs.Ultrasound as a mechanical wave has the advantages of non-invasive,high controllability and high tissue penetration ability,so it is widely used in clinical diagnosis.In this paper,bovine serum albumin(BSA)nanoparticles were synthesized and used as a carrier for chemotherapeutic drugs.A new type of ultrasound-regulated drug delivery system was prepared,and its drug release ability under ultrasound and penetration in deep tissues were prepared.(1)We designed and prepared a nanoparticles BSA-ACVA-DOX which containing the anticancer drug Doxorubicin(DOX).BSA was used as the skeleton and ultrasonically cleavable4,4’-azobis(4-cyanovaleric acid)(ACVA)was used as the chemical cross-linking agent.The transmission electron microscopy and dynamic light scattering showed the prepared nanoparticles were uniformly distributed spherical,with a particle size of 171±2.8 nm and a Zeta potential of-19.8 mV.The DOX drug loading rate was 6.8%and the encapsulation rate was 94.5%.It has good stability in PBS buffer solution,and the particle size and polydispersity coefficient have not changed significantly within 7 days.It can quickly enter MCF-7 cells and localize in lysosomes within 30 min.It has good biocompatibility and the cell survival rate is more than 80%after incubation at 200 mg/L for 24 h.(2)1MHz,2.0 W/cm~2 was used as safe ultrasound conditions.And It was verified that the ultrasound conditions used in the experiment had no significant effects on biological macromolecules such as proteins,nucleic acids and enzymes.In vitro tests showed that the structure of BSA-ACVA-DOX nanoparticles was obviously destroyed under ultrasound stimulation(1.0 MHz,2.0 W/cm~2).The controlled"Off-On"release of drugs in the body can be achieved by exogenous ultrasound.The release rate can reach 16%within 30 s,and can be increased to 74%within 10 min.Ultrasound gives the system good tissue penetration ability.The DOX release rate is 35%under 1 cm tissue thickness in 3 minutes and 32%at 2 cm tissue thickness.Cytotoxicity experiments showed that the tumor cells can be effectively killed after3 min of ultrasound,and the cell survival rate is only 17%In summary,the albumin nanoparticles BSA-ACVA-DOX have good ultrasound-activated rapid drug release capabilities with high biosecurity and tissue permeability.It can controllable release drugs in space and time as a smart drug.The-ACVA-DOX NPs has a broad application prospects as a drug delivery system.更多还原