卵巢癌患者血浆蛋白冠的形成及其对纳米粒靶向性的影响

纳米制剂进入体内环境后,可以自发地吸附血液中的蛋白质等生物大分子形成蛋白冠,并影响其在体内的预期功能。在不同的生理状态下,血浆蛋白的种类和含量不同,形成蛋白冠后对纳米粒的影响也不同。为此,本研究合成了叶酸(FA)修饰的聚乳酸-羟基乙酸共聚物(PLGA)纳米粒(PLGA-FA),以仅有聚乙二醇(PEG)修饰的纳米粒(PLGA-PEG)为对照组,探究了主动靶向纳米粒在健康人和卵巢癌患者血浆中蛋白冠的形成,以及对其靶向性的影响。血样取自北京大学第三医院,并获得北京大学第三医院医学科学研究伦理委员会伦理审查通过[批件号码:(2019)医伦审第(409-1)号]。动态光散射结果表明,PLGA-FA和PLGA-PEG形成蛋白冠后粒径增加了1040 nm,绝对电位降低了30 mV;SDS-PAGE凝胶电泳结果表明,在分子质量为45、110和大于180 kDa的蛋白条带,吸附在PLGA-FA上的健康人血浆蛋白和卵巢癌患者血浆蛋白的含量明显不同;流式细胞摄取实验结果表明,PLGA-FA与卵巢癌患者血浆孵育形成蛋白冠后,在卵巢癌细胞SKOV3中的摄取量降低。综上所述,主动靶向纳米粒在与卵巢癌患者血浆共孵育形成蛋白冠后,丧失了纳米粒的主动靶向性。本研究将为病理条件下主动靶向纳米粒的有效性提供参考,了解特定疾病下蛋白冠的形成对纳米制剂的影响,可以加速纳米制剂的临床转化。     

表面修饰脂质纳米粒给药系统的研究进展

脂质纳米粒是一种极具潜力的新型药物传输载体,对脂质纳米粒表面修饰是近年来的研究热点。通过表面修饰的手段能有效的避免单核巨噬细胞的吞噬、延长脂质纳米粒在体内的循环时间、主动靶向于病灶部位。本文就脂质纳米粒的体内命运及脂质纳米粒表面修饰的研究进展做一综述。     

长循环纳米粒

本文从影响纳米粒体内过程的因素入手,着重讨论纳米粒的特性对纳米粒体内循环时间的影响,综述了长循环纳米粒的制备及体内、体外评价方法。长循环纳米粒是医药学领域一个新的研究热点,对其进行深入研究将推动载体给药系统的进一步发展,具有重要的科学和应用价值。     

聚乳酸纳米粒给药系统研究进展

目的:综述国内外PLA纳米粒的近期研究进展.方法:检索分析文献资料,对PLA纳米粒的制备方法、表面修饰对纳米粒性质的影响、纳米粒中药物释放的影响因素、体内研究及应用情况进行概述.结果:PLA纳米粒可作为注射、口服、直肠给药、鼻腔给药的载体,延长药物半衰期,提高药物生物利用度,改变药物体内分布,减少药物不良反应.结论:PLA纳米粒给疾病的临床治疗提供了更多的手段和可能,PLA纳米粒的研究和应用具有广阔的前景.     

长循环纳米粒与肿瘤的细胞靶向研究进展

可用作抗肿瘤药物研究中的载药纳米粒包括脂质体、聚合物胶束、脂复合物及一些聚合物。为保证纳米粒的成功靶向,需要延长其在血液中的循环时间。长循环纳米粒可以达到这一效果,其最常用的修饰聚合物是聚乙二醇（PEG）。这一类聚合物可以将粒子表面隐藏起来,从而“躲过”,单核吞噬细胞系统（MPS）的吸收和血浆蛋白的调理,增加在血液中的循环时间,达到缓释的效果。与此同时,纳米粒在到达病理靶部位时,将采取一定方式裂解、释药或直接与肿瘤细胞结合并内化,达到控释效果。起到相应的治疗作用,本文就长循环纳米粒靶向肿瘤细胞这方面的相关研究做一综述。     

聚乳酸-羟基乙酸纳米粒表面功能化修饰及其应用

聚乳酸-羟基乙酸(PLGA)纳米粒表面特性是影响其体内分布的重要因素,经表面修饰的PLGA纳米粒已广泛应用于靶向给药系统研究.本文综述了PLGA纳米粒表面修饰的方法,包括共价交联、静电作用及疏水作用力等,概述了表面修饰纳米粒在非特异性生物黏附和生物渗透、特异性靶向、延长体循环时间及稳定生物活性分子方面的应用.     

聚乳酸纳粒给药系统研究进展

目的：综述国内外PLA纳米粒的近期研究进展。方法：检索分析文献资料，对PLA纳米粒的制备方法、表面修饰对纳米粒性质的影响、纳米粒中药物释放的影响因素、体内研究及应用情况进行概述。结果：PLA纳米粒可作为注射、口服、直肠给药、鼻腔给药的载体，延长药物半衰期，提高药物生物利用度，改变药物体内分布，减少药物不良反应。结论：PLA纳米粒给疾病的临床治疗提供了更多的手段和可能，PLA纳米粒的研究和应用具有广阔的前景。     

基因壳聚糖纳米粒表面修饰和转染研究

目的:研究递送基因纳米粒表面修饰对体外基因转染的影响.方法:利用末端活化的聚乙二醇(PEG)制备PEG化基因壳聚糖纳米粒;通过两端活化的PEG将糖蛋白配基连接到纳米粒表面,完成肝靶向纳米粒的制备;用透射电镜观察表面修饰对纳米粒粒径大小、粒子形态的影响;使用蛋白质测定试剂盒测算纳米粒表面蛋白连接量;利用体外转染实验考察表面修饰对纳米粒转染活性的影响;用倒置荧光显微镜观察并用流式细胞仪测定转染结果.结果:纳米粒PEG化使转染效率大幅度升高,半乳糖基牛血清白蛋白(Galn-BSA)使体系的转染效率比PEG化纳米粒略有下降,但比不经修饰的纳米粒转染活性高.壳聚糖纳米粒的表面PEG化能提高纳米粒的体外稳定性,从而提高体外转染效率,并适合于进行冷冻干燥.结论:长循环壳聚糖基因递送纳米粒在基因治疗研究中可能会发挥重要作用.     

醋酸地塞米松聚乙二醇化纳米粒的制备及兔体内药动学研究

目的：制备醋酸地塞米松聚乙二醇（PEG）化纳米粒,并测定其在兔体内的药动学参数。方法：以高压均质法制备醋酸地塞米松PEG化纳米粒,用扫描电镜观察纳米颗粒的形态,用激光粒度分析仪测定粒径。建立检测血浆中醋酸地塞米松浓度的HPLC法,以醋酸地塞米松溶液和普通纳米粒作为对照,测定醋酸地塞米松PEG化纳米粒在兔体内的药动学参数。结果：PEG化纳米粒平均粒径为（180±7）nm。体内半衰期为4.79h,AUC0～12为11.81mg.min.L-1,平均滞留时间为3.15h,重要药动学参数比普通纳米粒及溶液剂增加近1倍。结论：醋酸地塞米松PEG化纳米粒可以延长醋酸地塞米松在兔体内的半衰期,达到体内长循环的目的;其表观特征与普通载药纳米粒无明显差异。     

细胞膜修饰纳米粒药物递送系统的研究进展

纳米粒是药物递送系统研究的热点之一,但仍存在体内循环时间短,易被网状内皮系统识别和清除等缺点,限制了其临床应用。近年来,天然细胞膜成分和纳米技术的结合为解决这些问题提供了新的方案。一种由纳米粒核和细胞膜壳组成的新型仿生系统极大地改善了纳米粒的性能。用细胞膜修饰的纳米粒具有独特的功能,如延长血液循环时间,提高主动靶向和增强细胞内化等功能。本文综述了细胞膜修饰纳米粒药物递送系统的最新进展及其在癌症治疗方面的应用前景。     

Serum opsonins and liposomes: their interaction and opsonophagocytosis.

Removal of intravenously injected liposomes from the circulation is achieved by cells of the mononuclear phagocyte system, also known as the reticuloendothelial system. On exposure to blood, liposomes become coated with plasma proteins; some of these proteins (opsonins) are thought to determine their recognition by mononuclear phagocytes. This review provides a critical discussion of factors that control opsonization of liposomes and their phagocytosis in vivo and in vitro.     

Size,shape, charge and “stealthy” surface: Carrier properties affect the drug circulation time in vivo

The present review sets out to discuss recent developments of the effects and mechanisms of carrier properties on their circulation time. For most drugs, sufficient in vivo circulation time is the basis of high bioavailability. Drug carrier plays an irreplaceable role in helping drug avoid being quickly recognized and cleared by mononuclear phagocyte system, to give drug enough time to arrive at targeted organ and tissue to play its therapeutic effect. The physical and chemical properties of drug carriers, such as size, shape, surface charge and surface modification, would affect their in vivo circulation time, metabolic behavior and biodistribution. The final circulation time of carriers is determined by the balance between macrophage recognitions, blood vessel penetration and urine excretion. Therefore, when designing the drug delivery system, we should pay much attention to the properties of drug carriers to get enough in vivo circulation time to arrive at target site eventually. This article mainly reviews the effect of carrier size, size, surface charge and surface properties on its circulation time in vivo, and discusses the mechanism of these properties affecting circulation time. This review has reference significance for the research of long-circulation drug delivery system.     

Size,shape, charge and “stealthy” surface: Carrier properties affect the drug circulation time in vivo

The present review sets out to discuss recent developments of the effects and mechanisms of carrier properties on their circulation time. For most drugs, sufficient in vivo circulation time is the basis of high bioavailability. Drug carrier plays an irreplaceable role in helping drug avoid being quickly recognized and cleared by mononuclear phagocyte system, to give drug enough time to arrive at targeted organ and tissue to play its therapeutic effect. The physical and chemical properties of drug carriers, such as size, shape, surface charge and surface modification, would affect their in vivo circulation time, metabolic behavior and biodistribution. The final circulation time of carriers is determined by the balance between macrophage recognitions, blood vessel penetration and urine excretion. Therefore, when designing the drug delivery system, we should pay much attention to the properties of drug carriers to get enough in vivo circulation time to arrive at target site eventually. This article mainly reviews the effect of carrier size, size, surface charge and surface properties on its circulation time in vivo, and discusses the mechanism of these properties affecting circulation time. This review has reference significance for the research of long-circulation drug delivery system.     

Biodistribution and pharmacokinetic analysis of long-circulating thiolated gelatin nanoparticles following systemic administration in breast cancer-bearing mice

The objective of the present study was to modify thiolated gelatin nanoparticles with poly(ethylene glycol) (PEG) chains and examine their long circulating and tumor-targeting properties in vivo in an orthotopic a human breast adenocarcinoma xenograft model. The crosslinked nanoparticle systems were characterized to have a size of 150-250 nm with rapid payload release properties in a highly reducing environment. Upon PEG modification, the nanoparticle size increased to 300-350 nm in diameter. The presence of PEG chains on the surface was confirmed by characterization with electron spectroscopy for chemical analysis. The in vivo long-circulating potential, biodistribution and passive tumor targeting of the controls, and PEG-modified thiolated gelatin nanoparticles were evaluated by injecting indium-111 (111In)-labeled nanoparticles into breast tumor (MDA-MB-435)-bearing nude mice. Upon modification with PEG, the nanoparticles were found to have longer circulation times, with the plasma and tumor half-lives of 15.3 and 37.8 h, respectively. The results also showed preferential localization of thiolated nanoparticles in the tumor mass. The resulting nanoparticulate systems with long circulation properties could be used to target encapsulated drugs and genes to tumors passively by utilizing the enhanced permeability and retention effect of the tumor vasculature.     

Surface loading of nanoparticles on engineered or natural erythrocytes for prolonged circulation time: strategies and applications

Nano drug-delivery systems (DDS) may significantly improve efficiency and reduce toxicity of loaded drugs, but a few nano-DDS are highly successful in clinical use. Unprotected nanoparticles in blood flow are often quickly cleared, which could limit their circulation time and drug delivery efficiency. Elongating their blood circulation time may improve their delivery efficiency or grant them new therapeutic possibilities. Erythrocytes are abundant endogenous cells in blood and are continuously renewed, with a long life span of 100–120 days. Hence, loading nanoparticles on the surface of erythrocytes to protect the nanoparticles could be highly effective for enhancing their in vivo circulation time. One of the key questions here is how to properly attach nanoparticles on erythrocytes for different purposes and different types of nanoparticles to achieve ideal results. In this review, we describe various methods to attach nanoparticles and drugs to the erythrocyte surface, and discuss the key factors that influence the stability and circulation properties of the erythrocytes-based delivery system in vivo. These data show that using erythrocytes as a host for nanoparticles possesses great potential for further development.Keyword: drug delivery systems, nanoparticle, erythrocytes, prolonged circulation time     

Preclinical studies to understand nanoparticle interaction with the immune system and its potential effects on nanoparticle biodistribution

Nanoparticles have unique physicochemical properties which make them promising platforms for drug delivery. However, immune cells in the bloodstream (such as monocytes, platelets, leukocytes, and dendritic cells) and in tissues (such as resident phagocytes) have a propensity to engulf and eliminate certain nanoparticles. A nanoparticle's interaction with plasma proteins (opsonins) and blood components (via hemolysis, thrombogenicity and complement activation) may influence uptake and clearance and hence potentially affect distribution and delivery to the intended target sites. Nanoparticle uptake by the immune cells is influenced by many factors. Different nanoparticles have been shown to act on different pathways, while various characteristics/properties also affect which pathway is employed for particle internalization. Nanoparticle protein binding occurs almost instantaneously once the particle enters biological medium, and the physical properties of such a particle-protein complex are often different than those of the formulated particle. These new properties can contribute to different biological responses and change nanoparticle biodistribution. Therefore, in the situation when specific delivery to immune cells is not desired, the ideal nanoparticle platform is the one whose integrity is not disturbed in the complex biological environment, which provides extended circulation in the blood to maximize delivery to the target site, is not toxic to blood cellular components, and is "invisible" to the immune cells which can remove it from circulation. This review discusses the most recent data on nanoparticle interactions with blood components and how particle size and surface charge define their hematocompatibility. This includes properties which determine particle interaction with plasma proteins and uptake by macrophages. We will also provide an overview of in vitro methods useful in identifying interactions with components of the immune system and the potential effects of such interaction on particle distribution to tissues.     

消炎去脂片对小鼠免疫功能的影响

目的 :探讨消炎去脂片对小鼠非特异性免疫和特异性免疫功能的影响。方法 :用炭粒廓清法测定小鼠单核吞噬细胞的吞噬功能 ;用鸡红细胞免疫小鼠后测定鸡免疫血清溶血素抗体水平。结果 :消炎去脂片能增强小鼠单核吞噬细胞的吞噬功能 ,促进B淋巴细胞产生抗体 ,用药各组与空白组相比有显著性差异 (P<0 05)。结论 :消炎去脂片能明显增强小鼠的免疫功能     

Effects of protein binding on the biodistribution of PEGylated PLGA nanoparticles post oral administration

The surface of nanoparticles is often functionalised with polymeric surfactants, in order to increase systemic circulation time. This has been investigated mainly for intravenously administered nanoparticles. This study aims to elucidate the effect of surface coating with various concentrations of polymeric surfactants (PEG and Pluronics F127) on the in vitro protein binding as well as the tissue biodistribution, post oral administration, of PLGA nanoparticles. The in vitro protein binding varied depending on the polymeric surfactant used. However, in vivo, 1% PEG and 1% Pluronics F127 coated particles presented similar biodistribution profiles in various tissues over seven days. Furthermore, the percentage of PEG and Pluronics coated particles detected in plasma was higher than that of uncoated PLGA particles, indicating that systemic circulation time can also be increased with oral formulations. The difference in the in vitro protein binding as a result of the different poloxamers used versus similar in vivo profiles of these particles indicates that in vitro observations for nanoparticles cannot represent or be correlated to the in vivo behaviour of the nanoparticles. Our results therefore suggest that more studies have to be conducted for oral formulations to give a better understanding of the kinetics of the particles.     

Nanoparticles with decreasing surface hydrophobicities: influence on plasma protein adsorption

The rapid uptake of i.v. injected nanoparticles by cells of the mononuclear phagocytic system (MPS) is a major obstacle for a long blood circulation time and a drug targeting to sites other than the MPS. The adsorption of proteins on the particles surface after i.v. administration depends on their surface characteristics and is regarded as key factor for the in vivo organ distribution. The objective of this study is to investigate changes in the plasma protein adsorption patterns in the course of surface hydrophobicity variation. Latex particles with decreasing surface hydrophobicity were synthesized as model colloidal carriers. Physicochemical characterization had been performed and considerable differences in the protein adsorption patterns on the particles could be detected by using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Correlations between physicochemical characteristics and the protein adsorption patterns have been found and are discussed.