基因药物纳米给药系统的设计与研究进展

基因药物的传递面临着体内外稳定性差、缺乏靶向性、难入胞、在细胞内难以释放等一系列障碍和挑战。因此,要实现基因药物在 体内有效传递需构建能克服这些障碍的药物传递系统。随着材料科学和纳米科技的发展,大量新型的纳米载体已被用于基因药物的传递。 综述目前基因药物传递所面临的障碍和挑战,基因药物纳米给药系统的设计思路及研究进展。     

肿瘤靶向纳米载药系统的设计与构建

近年来将纳米载药系统应用于肿瘤靶向递药的研究层出不穷。与正常组织相比,肿瘤组织具有较低的pH环境、大量新生血管生成、 不规则的血流灌注、局部缺氧等特异性的微环境,利用这些特点进行合理的纳米载药系统设计能够实现肿瘤部位的高效递药及深层穿透, 显著提高肿瘤治疗效果。针对现有的肿瘤靶向纳米载药系统的构建与设计方法进行综述,以阐述纳米载药系统在肿瘤靶向传递中的研究进展     

三种不同表面活性剂对羟基磷灰石纳米颗粒的表面修饰的比较

目的:本研究旨在通过不同方法修饰羟基磷灰石纳米颗粒并检测其稳定性及分散性。方法:首先采用水合热合成法制备羟基磷灰石纳米颗粒,然后用透射电镜(TEM)和场发射扫描电镜(SEM)对其表面形态结构进行表征。我们首次用溴化十六烷三甲基铵(CTAB),PEG2000和人血清对羟基磷灰石纳米颗粒通过共价结合或表面吸附的方式进行表面嫁接,并利用透射电镜,傅里叶红外光谱(FT-IR)和X射线衍射(XRD)对新合成的这三种纳米羟基磷灰石复合物的形貌,结构和晶粒粒径进行表征。对这三种羟基磷灰石纳米颗粒悬浮液的时间沉降曲线进行分析。在分散性上通过检测这三种羟基磷灰石复合物悬浮液在不同pH值下的Zeta电位并绘制Zeta-pH曲线。结果:我们发现CTAB修饰的羟基磷灰石纳米颗悬浮液的悬浮稳定性最佳,其次是PEG2000,最后是人血清。在pH=7.0时,CTAB修饰的羟基磷灰石纳米颗粒的zeta电位值是25.68 m V,而PEG2000修饰的Zeta电位是4.32m V,人血清修饰的Zeta电位是-13.23m V。结论:CTAB表面修饰的羟基磷灰石纳米颗粒相对于其它两种表面活性剂复合物具有更好的分散性和悬浮稳定性,与DNA/RNA结合能力更强。本课题的结果给羟基磷灰石纳米颗粒载体的应用提供了一种新的选择,有望利用亲和力更高的基因载体实现基因治疗,具有广阔的应用前景。     

新型γ-聚谷氨酸自组装纳米胶束的制备及用于蛋白载体的研究

对水溶性的γ-聚谷氨酸(γ-PGA)进行了接枝改性,合成了两亲性γ-聚谷氨酸(γ-PGA)接枝衍生物,采用超声探头法制备胆甾醇基γ-PGA自组装胶束,并以卵清蛋白(OVA)作为模型蛋白,研究其载药和释药性能.结果表明,制备的两亲性胆甾醇基γ-PGA自组装胶束平均粒径为299.6+ 27.3nm,粒径的多分散系数较窄(0.17),且具有较低的细胞毒性;其疏水核-亲水壳的纳米微结构对蛋白药物显示了良好载药性能,对OVA载药量可达118.8 μg/mg,包封率33.5％;体外释药结果显示,负载OVA的甾醇基γ-PGA自组装胶束能延缓蛋白的释放,释药速率与介质pH密切相关.     

新型纳米靶向给药系统载体材料的设计

新型纳米靶向给药系统的研究与开发对于难治愈性疾病（尤其是肿瘤）的治疗具有重大意义,而其发展很大程度上取决于载体材料 的设计。构思巧妙、设计合理的载体材料能使载体实现靶向功能,将药物定位浓集于病灶部位,并最大限度地发挥高效低毒的作用。基于 不同的靶向策略,包括被动靶向、主动靶向和响应肿瘤微环境的靶向,综述了近年来一些新型纳米载体材料的设计,为新型纳米靶向给药 系统的研究提供参考。     

核定位信号肽修饰的抗肿瘤纳米载药体系

纳米载药体系作为一类具有可控性和靶向性的药物递送工具,可以保护生物分子药物免于细胞内快速酶促降解、免于快速血液清除,确保将生物分子药物安全递送至作用部位,从而有效改善药物的生物利用度,提高药物疗效并降低毒副作用,在生物医学领域具有广阔的应用前景,在功能材料研究和肿瘤靶向治疗研究中受到广泛关注.近年来,通过使用功能性生物...     

双重响应二硫化钼纳米载药体系的制备及其性能研究

摘要 目的：制备肿瘤微环境响应释放的靶向二硫化钼纳米载药体系,并评价其载药量和释药性能。方法：以水热法合成的MoS₂纳米片为基底,利用MoS₂纳米片上的S空缺位点连接硫辛酸聚乙二醇羧酸,然后通过酰胺反应连接精氨酸-甘氨酸-天冬氨酸（RGD）靶向分子,再连接上交联剂3-(2-吡啶二硫代)丙酸N-琥珀酰亚胺酯（SPDP）,得到药物载体MoS2-PEG-RGD-SPDP（MPRS）,MPRS进一步与巯基化的阿霉素（DOX）反应,形成MPRS-DOX纳米载药体系。通过透射电子显微镜（TEM）,X-射线光电子能谱仪（XPS）以及纳米粒度电位仪对合成的材料进行表征;利用紫外可见分光光度计测试MPRS的载药性能,采用荧光分光光度计考察MPRS-DOX的释药性能。结果：成功合成MPRS-DOX纳米载药体系,其粒径大小在200 nm左右,Zeta电位为+28.2 mV;其载药效率为86.8%,载药量为53.5%。体外释药实验表明,在10 mM 谷胱甘肽（GSH）和pH=5.5的条件下DOX释放量最多。结论：成功制备了粒径合适的MPRS-DOX纳米载药体系,MPRS-DOX具有GSH和pH双重响应性,可实现预期的模拟肿瘤微环境内控制释放药物。这种GSH和pH双重响应的纳米载药体系为新一代刺激响应型纳米载药系统的构建提供了新的思路。     

综述——纳米材料与药物输递：基于聚合物的环境敏感型纳米抗肿瘤药物传输系统的研究

环境敏感型聚合物纳米抗肿瘤药物传递系统能够响应外界环境的微小刺激,引起自身结构的变化,释放出药物,在肿瘤治疗方面具长效低毒、可控及高载药量等优势,已被广泛应用于生物医学领域．本文介绍了聚合物环境响应型纳米药物传输系统的发展近况,并从pH 值敏感型、温度敏感型、氧化还原敏感型、酶敏感型以及其他敏感型给药系统角度,阐述了环境敏感型药物传输系统在抗肿瘤领域的研究现状及未来展望．     

嵌段共聚物聚乙二醇-聚苹果酸苄基酯载药胶束的制备及性质研究

目的：为构建聚合物胶束药物运载体系,制备嵌段共聚物聚乙二醇-聚苹果酸苄基酯载药胶束并测定其性质。方法：以L-天冬氨酸为原料,重氮化、环化后经开环聚合得到聚苹果酸苄基酯。氨基聚乙二醇通过酰胺键连接到β-聚苹果酸苄基酯上形成两亲性嵌段共聚物,喜树碱做药物模型制备载药胶束。动态光散射法测定胶束粒径、评价胶束稳定性,高效液相法测定喜树碱载药率和包封率,芘荧光法与动态光散射法测定临界胶束浓度。结果：喜树碱包封率72%,载药率6%,临界胶束浓度为40μg.mL-1。随着聚苹果酸苄基酯分子量减小,胶束稳定性增强。结论：聚乙二醇-聚苹果酸苄基酯在疏水链/亲水链分子量比值为2-4时在水中可自组装形成纳米胶束,可作为性能优良的聚合物药物载体。     

角蛋白载药纳米颗粒的制备及药物可控释放性能研究*

目的:以角蛋白作为药物载体材料,制备智能响应性药物递送系统,研究其药物装载和释放性能。方法:利用去溶剂法制备角蛋白纳米颗粒(KNP),以罗丹明B(RB)和姜黄素(Cur)为亲水性和疏水性模式药物,制备载药KNP。利用钨灯丝扫描电镜(SEM)、动态光散射(DLS)、傅里叶变换红外光谱(FTIR)和药物体外释放实验等对KNP的尺寸、形貌、结构、载药和释药性能进行研究。结果:成功制备出粒径均一、约为300 nm 的KNP,能够装载亲水性和疏水性药物。载药颗粒在体外释放研究中表现出pH和氧化还原双重响应性。结论:利用去溶剂法,简便、安全地制备了分散性良好且具有pH和氧化还原双重响应性释放特性的角蛋白载药纳米颗粒,为角蛋白作为智能响应型药物递送载体的研究和应用提供了参考。     

新的药物传递系统:外泌体作为药物载体递送*

外泌体(exosomes)是细胞分泌的囊泡,在细胞与细胞之间通信中发挥重要作用。由于其固有的长距离通信能力和出色的生物相容性而具有很大的潜力作为药物递送载体,尤其适合递送蛋白质、核酸、基因治疗剂等治疗药物。许多研究表明外泌体可以有效地将许多不同种类的货物递送至靶细胞,因此,它们常被作为药物载体用于治疗。对外泌体作为药物递送系统中面临的外泌体分离,药物装载和靶向治疗应用的进展与挑战作一介绍,以期更好为外泌体药物递送系统开发提供新思路。     

新的药物传递系统:外泌体作为药物载体递送*

外泌体(exosomes)是细胞分泌的囊泡,在细胞与细胞之间通信中发挥重要作用。由于其固有的长距离通信能力和出色的生物相容性而具有很大的潜力作为药物递送载体,尤其适合递送蛋白质、核酸、基因治疗剂等治疗药物。许多研究表明外泌体可以有效地将许多不同种类的货物递送至靶细胞,因此,它们常被作为药物载体用于治疗。对外泌体作为药物递送系统中面临的外泌体分离,药物装载和靶向治疗应用的进展与挑战作一介绍,以期更好为外泌体药物递送系统开发提供新思路。     

海藻酸钠漂浮微囊的制备以及载药应用研究

目的:本文研究了一种海藻酸钠漂浮微囊的制备方法用以实现胃部持续给药。方法:采用微胶囊发生器制备海藻酸钠漂浮微囊,壁材为海藻酸钠,芯材为食用油的漂浮微囊,衡量不同的制备参数对微囊的理化特性影响;采用克拉霉素作为模型脂溶性药物,测量漂浮药物递送系统的控制释放性质、以及微囊载药特性和小鼠体内漂浮验证。结果:成功制备出了具有漂浮特性的海藻酸钠微囊,其中泵送速度对微囊性质的影响最大。制备出的微囊具有低细胞毒性,可以实现90%的药物包埋率。此外,微囊可以在小鼠的胃中保存超过6小时,具有良好的漂浮特性。结论:海藻酸钠漂浮微囊是一种有效的胃部药物递送系统,可明显延长药物在胃部的滞留时间。     

Cochleates: New Lipid-Based Drug Delivery System

Abstract

Cochleates are a lipid-based tailored drug delivery system formed by the precipitation of a negatively charged lipid and a cation, for example phosphatidylserine and calcium. Hydrophobic, amphiphilic, negatively or positively charged moieties are suitable candidates to be delivered via cochleates. Various procedures have been developed allowing the control of cochleate particle size, including the trapping and hydrogel methods, which use either a direct addition or a slow diffusion of calcium into the negatively charged liposome/drug suspension. The efficacy of cochleates to encapsulate and deliver drugs was evaluated using amphotericin B as a model. Amphotericin B cochleates (CAMB) were compared to Fungizone® and AmBisome®, two commercially available AmB products. Parenterally, CAMB was given IP to ICR mice infected with Candida albicans. 100% survival was observed with low doses of CAMB (0.5 mg/kg/day, 10 days) compared to 60% for Fungizone, at the same dose. Tissue burden studies were conducted in parallel. Mice were treated daily from day 1 to day 7 post challenge and tissue burden assessed at day 8. In the kidneys, all three formulations were comparable in reducing colony counts. In the spleen, CAMB at 10 mg/kg/day was comparable to AmBisome given IV at the same dose. At 1 mg/kg/day, CAMB was more potent than Fungizone and AmBisome. Oral administration of CAMB in C57BL/6 mice, at 10 mg/kg results in high levels of AmB in target tissues. Multiple daily doses (10) showed accumulation of AmB in key tissues (liver, lungs, spleen, and kidneys) and AmB tissue concentrations are raised to therapeutic levels. Orally administered CAMB are highly effective against fungal infections in mice at very low doses. Balb/C mice were infected with Candida albicans and were given oral CAMB as a daily dose for 15 days. Comparison was done to AmBisome given orally at 10 mg/kg and Fungizone IP. 100% survival was obtained with CAMB at doses as low as 0.5 mg/kg/day (15 days). CAMB eradicate Candida from lungs when given at 2.5 mg/kg/day and was comparable to Fungizone given IP at almost the same dose (2 mg/kg/day). The comparison between CAMB and AmBisome shows that oral CAMB is 10 times more effective than oral AmBisome in reducing colony counts in both kidneys and lungs. Orally administered CAMB were non-toxic even at the highest dose of 50 mg/kg/day (14 days). This was demontrated by 100% survival of the animals and normal histopathology analysis. No lesions in the kidneys, GI tract, lungs, liver and spleen was observed despite the substantial amount of AmB in these organs. AmB cochleate promise to be a safe, broad spectrum, effective and orally available, antifungal formulation.     

还原可降解聚磺酸甜菜碱型纳米水凝胶的制备及载药研究

目的:制备与表征还原可降解的聚磺酸甜菜碱型纳米水凝胶,利用该纳米递药系统包载阿霉素(DOX)并初步评价其抗肿瘤性能。方法:利用回流沉淀聚合的方法合成含二硫键的聚磺酸甜菜碱甲基丙烯酸酯(PSBMA)纳米水凝胶及不含二硫键的PSBMA纳米凝胶(nd-PSBMA);通过粒度仪和透射电镜考察两种纳米水凝胶的粒径、形态以及稳定性;通过考察谷胱甘肽(GSH)对纳米凝胶溶液相对浊度的影响以评价还原环境对两种纳米凝胶的还原可降解性;利用纳米凝胶包载阿霉素(DOX),考察载药凝胶在GSH中的释药行为,并初步评价其对A549肿瘤细胞的杀伤作用。结果:以N, N'-双丙烯酰胱胺为交联剂制备了含二硫键的PSBMA纳米凝胶,其粒径在180～200 nm;同时以N, N'-双丙烯酰胺为交联剂制备了不含二硫键的n-PSBMA纳米凝胶。两种纳米凝胶与小鼠血清共孵育7天水合粒径仍无明显变化,表明磺酸甜菜碱型纳米凝胶具有良好的抗蛋白吸附能力。此外,PSBMA纳米凝胶在GSH溶液中迅速地降解,且降解速度与GSH浓度呈正相关;而nd-PSBMA纳米凝胶在GSH溶液中几乎不降解。载DOX的PSBMA纳米凝胶可在GSH作用下快速的释放药物而载DOX的nd-PSBMA纳米凝胶在GSH作用下缓慢的释放药物;体外细胞实验显示空白纳米凝胶和载药nd-PSBMA对A549细胞无明显毒性作用,但载DOX的PSBMA纳米凝胶可高效地杀死A549肿瘤细胞,其药效与游离DOX相仿。结论:还原可降解的PSBMA纳米水凝胶有望成为智能型控释药物载体。     

CNS Drug Design Based on Principles of Blood-Brain Barrier Transport

Abstract: Lipid-soluble small molecules with a molecular mass under a 400–600-Da threshold are transported readily through the blood-brain barrier in vivo owing to lipid-mediated transport. However, other small molecules lacking these particular molecular properties, antisense drugs, and peptide-based pharmaceuticals generally undergo negligible transport through the blood-brain barrier in pharmacologically significant amounts. Therefore, if present day CNS drug discovery programs are to avoid termination caused by negligible blood-brain barrier transport, it is important to merge CNS drug discovery and CNS drug delivery as early as possible in the overall CNS drug development process. Strategies for special formulation that enable drug transport through the blood-brain barrier arise from knowledge of the molecular and cellular biology of blood-brain barrier transport processes.     

Optimization of Drug Loading Procedures and Characterization of Liposomal Formulations of Two Novel Agents Intended for Boron Neutron Capture Therapy (BNCT)

Abstract

The characterization of two liposomal formulations of boronated DNA-interacting agents has been performed. It is shown that the two boronated drugs, WSA-Water Soluble Acridine and WSP-Water Soluble Phenantridine, can be encapsulated within unilamellar sterically stabilized liposomes with high drug-to-lipid ratios (up to 0.50:1 (mol:mol)), using transmembrane pH gradients. The steric stabilization of the liposomes was accomplished by the addition of DSPE-PEG(2000) (PEG-lipid) to DSPC/Cho lipid mixtures and the composition used was DSPC: Cho: DSPE-PEG 55:40:5 (moI%). The loading of the drugs resulted in drug precipitation in the liposomal aqueous core as observed by cryo-transmission electron microscopy (c-TEM). Moreover, it is shown that when pH gradients across the bilayer were used for remote loading of WSP or when ammonium sulfate gradients were used for remote loading of WSA, the formation of small bilayer fragments (discs) was induced. We present compelling evidence that the formation of discs is a consequence of precipitate growth in the liposomal interior. The precipitate growth causes some of the liposomes to rupture resulting in the above mentioned disc-formation and a substantial decrease in trapping efficiency. The in vitro stability of the drug loaded liposomes was excellent, both in buffer and in 25% human serum. For most of the formulations, the release of the drugs was below or around 10% after 24 hours at 37^oC. Furthermore, the influence of initial internal pH and internal buffering capacity on release properties of WSA and WSP were investigated. It is shown that the release profiles of the drugs can be controlled, to a large extent, by varying the composition of the internal liposomal aqueous phase.     

The 78 kDa glucose-regulated protein (GRP78/BIP) is expressed on the cell membrane,is released into cell culture medium and is also present in human peripheral circulation

In human rabdomiosarcoma cells (TE671/RD) chronic exposure to 500 nM thapsigargin (a powerful inhibitor of the endoplasmic reticulum Ca²⁺-ATPases) resulted in the induction of the stress protein GRP78/BIP. Making use of the surface biotinylation method, followed by the isolation of the GRP78 using ATP-agarose affinity chromatography, it was found that a fraction of the thapsigargin-induced GRP78 is expressed on the cell surface. The presence of GRP78 on the membrane of thapsigargin-treated cells was confirmed by fractionation of cell lysates into a soluble and a membrane fraction, followed by Western blot analysis with an anti-GRP78 antibody. It was also found that conspicuous amounts of GRP78 are present in the culture medium collected from thapsigargin-treated cultures. This extracellular GRP78 originates mostly by an active release from intact cells and does not result solely from the leakage of proteins from dead cells. Moreover, small amounts of circulating, free GRP78 and naturally-occurring anti-GRP78 autoantibodies were detected in the peripheral circulation of healthy human individuals.     

DNA折纸纳米载体在药物递送中的应用

DNA纳米技术是基于沃森克里克碱基配对原则产生可编程核酸结构的技术。因其具有高精度的工程设计、前所未有的可编程性和内在的生物相容性等特点，运用该技术合成的纳米结构不仅可以与小分子、核酸、蛋白质、病毒和癌细胞相互作用，还可以作为纳米载体，递送不同的治疗药物。DNA折纸作为一种有效的、多功能的方法来构建二维和三维可编程的纳米结构，是DNA纳米技术发展的一个里程碑。由于其高度可控的几何形状、空间寻址性、易于化学修饰，DNA折纸在许多领域具有巨大的应用潜力。本文通过介绍DNA折纸的起源、基本原理和目前进展，归纳总结了运用DNA折纸进行药物装载和释放的方式，并基于此技术，展望了今后的发展趋势以及所面临的机遇和挑战。     

Cripto stabilizes GRP78 on the cell membrane

The ER resident chaperone molecule GRP78 has been shown to translocate to the cell surface where it associates with Cripto and signals cell growth, playing a still partially understood role in tumorigenesis. Consequently, a better understanding of GRP78 topology and structure at the surface of cancer cells represents an important step in the development of a new class of therapeutics. Here, we used a set of programs for creation of a complex containing GRP78 and Cripto proteins. We elucidated possible interactions of GRP78, Cripto, and their complex with the membrane. Using molecular dynamics simulations, we demonstrated that Cripto binding to GRP78 completely changes the dynamics of its behavior on the membrane, not allowing GRP78 to disconnect from it, thus enabling GRP78 tumorigenic functions.