精氨酸-甘氨酸-天冬氨酸肽类似物与新生血管内皮靶向治疗

背景：血管内皮是缺血、血栓、炎症、水肿、氧化应激等病理损伤中的重要部位,选择特异性的内皮细胞靶点成为药物介入治疗的关键。 目的：分析和总结近年来精氨酸-甘氨酸-天冬氨酸肽及精氨酸-甘氨酸-天冬氨酸多肽类似物作为特异性的内皮细胞靶点的研究。 方法：分别以“RGD、整合素、靶向治疗”,“RGD、integrin 、targeted therapy” 为检索词,应用计算机检索Pubmed 数据库1998年1月至2011年12月有关文章。纳入有关血管新生的文献。排除与研究目的无关和内容重复者。保留42篇文献做进一步分析。 结果与结论：整合素αvβ3是内皮细胞病理损伤及血管新生时的特异靶点,参与内皮细胞的迁移、增殖、分化过程。精氨酸-甘氨酸-天冬氨酸肽及精氨酸-甘氨酸-天冬氨酸多肽类似物作为整合素和其配体相互作用的识别位点,能结合肿瘤或者病理损伤时新生血管表达增高的整合素αvβ3,介导细胞与细胞外基质及细胞之间的相互作用,可在新生血管显影、靶向药物递送、载体材料修饰中发挥重要作用。     

盐酸表阿霉素纳米靶向制剂的缓释效应

背景：盐酸表阿霉素是一种广谱抗生素,目前临床使用的不足多为药物释放快、目标组织药物浓度低,静脉给药后广泛分布于体内各种组织器官,不良反应明显。 目的：针对盐酸表阿霉素临床应用的不足,制备盐酸表阿霉素纳米靶向注射制剂。 方法：以叶酸偶联牛血清白蛋白为载体,采用乳化-高压匀质法,制备盐酸表阿霉素纳米靶向注射制剂,以激光粒度分析仪测定纳米颗粒的粒径大小、粒径分布及Zeta电位,扫描电镜观察纳米颗粒的表面形态,高效液相色谱法分析白蛋白负载盐酸表阿霉素纳米制剂的包封率、载药量和释药性能。 结果与结论：制备的盐酸表阿霉素纳米粒外观呈均匀球型,粒径分布较窄,平均粒径为(157.73±     0.40) nm,平均 Zeta 电位为(-30.85±0.43) mV,载药量 22.78%,包封率可达96.24%。体外模拟释药结果表明药物释放曲线分为两个阶段,突释阶段微球释药量在24 h内达42.6%,缓释阶段纳米粒释药持续时间长,在112 h 时释药量达 84.1%,载药纳米粒的药物释放速率持续稳定。结果表明乳化结合高压匀质法制备的盐酸表阿霉素纳米靶向制剂粒径均匀,粒径范围分布窄,载药量和包封率高,具有一定的缓释作用。     

甘草酸表面修饰万乃洛韦白蛋白纳米粒的制备及其肝靶向性研究

以万乃洛韦为模型药物 ,去溶剂化法制备普通载药纳米粒 ,结合高碘酸盐氧化法制备甘草酸 -万乃洛韦白蛋白纳米粒偶联物。对其表面甘草酸密度、形态、大小及其分布、体外释药特性、载药量、包封率、动物体内肝分布和体外肝细胞的摄取情况进行了研究。修饰纳米粒表面甘草酸密度为 9;平均粒径 d0 .5=2 6 8± 2 3nm;载药量1.35 % ;包封率 6 8.76 % ;体外释药符合双相动力学规律 ;对肝细胞具有选择靶向性。静注 15 min后 ,有 6 9.89%集中在肝脏 ,对照组为 6 4 .82 % ,二者之间存在显著差异 (P<0 .10 )。甘草酸表面修饰白蛋白纳米粒制备成功 ,为肝细胞靶向给药提供了新途径。     

载异烟肼利福平聚乳酸纳米粒的制备及体外释药**

背景：微载体药物因具有靶向性、控释性、稳定性、更好的安全性备受关注。 目的：观察载异烟肼利福平两种抗结核药于同一聚乳酸纳米粒的给药系统及体外释放特性。 方法：采用改良的自乳化二元溶剂扩散法制备载异烟肼和利福平纳米粒,亚微粒径分析仪测定纳米粒粒径及分布,透射电镜观察其形态;高效液相色谱仪建立测定异烟肼、利福平的载药量和包封率;以磷酸盐缓冲液为释放介质,观察载异烟肼和利福平纳米粒的体外释药特性。 结果与结论：载利福平和异烟肼纳米粒表面完整光滑,无明显粘连现象,纳米粒均匀度好。亚微粒径分析仪测定纳米粒平均粒径80.4 nm。异烟肼载药量为(15.95±1.34)%,包封率为(5.01±0.17)%;利福平载药量为(4.66±0.97)%,包封率为(4.05±0.18)%。体外释药结果显示纳米粒的体外释药过程较平稳。突释期纳米粒中异烟肼释放度为15.22%,到3 d累积释放度可达95.6%;利福平释放度为9.26%,到3 d累积释放度可达90.3%。提示采用改良的自乳化二元溶剂扩散法制备载异烟肼和利福平纳米粒,所得载药纳米粒的粒径小且较均匀。纳米粒体外释药过程较平稳,无明显突释现象。关键词：聚乳酸;异烟肼;利福平;纳米粒;体外释药 doi:10.3969/j.issn.1673-8225.2012.16.014     

脑主动靶向载内吗啡肽纳米粒的制备及其镇痛作用的实验研究

目的 制备新型载镇痛药物内吗啡肽的耦联脑主动靶向抗体OX26纳米粒,研究其镇痛作用.方法 利用新型材料超支化聚甘油-聚乳酸-聚乙醇酸(HBPG-PLGA)通过复合乳液法制备载镇痛药内吗啡肽的纳米粒,在其表面耦联转铁蛋白受体单克隆抗体OX26,通过扫描电子显微镜等进行表征;通过尾静脉注射不同配方纳米粒,考察纳米粒透过血-脑屏障及其对慢性坐骨神经结扎(CCI)大鼠模型镇痛作用.结果 载内吗啡肽HBPG-PLGA纳米粒制备方法稳定,在扫描电子显微镜下呈核壳结构,平均粒径(170±20)nm,Zeta电位约-27 mV,与抗体OX26的耦联效果较好,药物可以缓慢释放72 h以上.尾静脉注射耦联抗体OX26载内吗啡肽纳米粒对CCI大鼠具有较好的镇痛作用,未耦联抗体OX26纳米粒只在给药后45 min时间点显示微弱镇痛作用,静脉注射内吗啡肽和空白纳米粒未显示镇痛作用.结论 耦联抗体OX26载内吗啡肽纳米粒制备稳定,达到较好透血-脑屏障作用,对CCI大鼠有良好镇痛作用.     

叶酸靶向载紫杉醇磷脂-聚合物杂化纳米粒的制备及其体外细胞评价

目的 制备具有叶酸靶向性的载紫杉醇磷脂-聚合物杂化纳米粒(PTX-FLPNPs),并研究其对乳腺癌细胞EMT-6的细胞毒性及体外细胞吞噬.方法 以聚己内酯-聚乙二醇-聚己内酯(PCL-PEG-PCL)、二硬脂酰基磷脂酰乙醇胺-甲氧基聚乙二醇(DSPE-mPEG2000)和叶酸偶联的磷脂(Folate-PEG(2000)-DSPE)为药物载体,通过薄膜水化法自组装制备PTX-FLPNPs,并对其进行表征;使用激光扫描共聚焦显微镜观察比较叶酸受体高表达的乳腺癌细胞EMT-6对叶酸靶向及无靶向杂化纳米粒的吞噬作用;采用MTS法研究PTX-FLPNPs对EMT-6细胞的细胞毒性.结果 成功制备了PTX-FLPNPs,其呈球形,粒径均匀,具有明显的“核-壳”结构.投药量为30％的PTX-FLPNPs的平均粒径为(279.9±8.7)nm,多分散系数为0.173±0.021,Zeta电位为(-17.5±1.1)mV,载药量为(27.36±0.91)％,包封率为(91.16±1.12)％.细胞吞噬实验表明,叶酸受体高表达的EMT-6细胞对叶酸靶向的杂化纳米粒的吞噬作用明显强于无靶向的杂化纳米粒(P＜0.05).细胞毒性实验结果表明,PTX-FLPNPs的细胞毒性低于紫杉醇注射剂,且对肿瘤细胞的抑制效果优于无靶向的杂化纳米粒.结论 PTX-FLPNPs具有较高载药量及包封率,粒径均匀,可通过主动靶向作用介导肿瘤细胞内吞,并增加药物在肿瘤细胞内的浓度,是一种能有效抑制肿瘤的靶向载药纳米制剂.     

Fe3O4磁性微粒的制备及表征

背景：磁性微粒作为一种磁性载体在固定化酶、免疫检测、靶向载药治疗及细胞分离等生物医学领域得到了广泛的应用。 目的：制备分散稳定性好,相对磁性强的纳米级Fe₃O₄微粒。 方法：以氯化亚铁、氯化铁、氢氧化钠为主要原料,采用化学共沉淀法合成Fe₃O₄磁性粒子。 结果与结论：用正交设计法优化了Fe₃O₄微粒的合成工艺条件,得到制备Fe₃O₄粒子的最佳实验条件为Fe²⁺/Fe³⁺的物质的量之比为2∶1、共沉淀时的pH值为11、熟化温度为90 ℃、表面活性剂聚乙二醇的用量为40 mL,此时制得的Fe₃O₄粒子粒径最小,为78 nm,Fe₃O₄溶液的分散稳定性最好,相对磁性最强。从Fe₃O₄的扫描电镜图可以看出,Fe₃O₄微粒晶体颗粒为纳米级。     

MUC1靶向性载药纳米粒的构建及其体外抗肿瘤效应的评估

目的构建MUC1靶向纳米粒,并在体外评估其抗肿瘤效应。方法 采用聚乳酸聚乙醇酸共聚物(PLGA)制备包载紫杉醇的纳米粒,并在表面偶联具有MUC1蛋白靶向性的核酸适配体。紫外分光光度法、动态光散射法测定MUC1靶向载药纳米粒的基本表征;以MUC1过表达的乳腺癌细胞MCF-7为实验组,肝癌细胞HepG2为对照组,用流式细胞仪检验纳米粒的选择性,MTS法评估其杀伤效果和IC50。结果 MUC1靶向载药纳米粒粒径(225.3±9.2)nm,药物包封率83.6%±1.7%,在体外可以特异性地被MUC1+癌细胞摄入,对MCF-7细胞杀伤作用显著强于普通载药纳米粒(P<0.01),IC50为1.52 mg/L。结论 该靶向纳米粒可以在体外特异性地增加MUC1+肿瘤细胞对纳米粒的摄入,降低IC50值,提高抗化疗药物对肿瘤细胞的杀伤效率。     

精氨酸甘氨酸天冬氨酸多肽表面修饰促进生物支架材料对骨髓来源 种子细胞的黏附

背景：精氨酸甘氨酸天冬氨酸多肽具有较强的黏附性和生物支架材料可接枝结合,且不会改变材料的表面理化性质。 目的：观察应用精氨酸甘氨酸天冬氨酸多肽表面修饰猪主动脉瓣去细胞支架材料对骨髓干细胞黏附性的影响。 方法：采用胰蛋白酶+TritonX-100法制备猪主动脉瓣去细胞支架材料,用YGRGDSP多肽(酪氨酸-甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸-脯氨酸)进行处理,按照精氨酸甘氨酸天冬氨酸多肽的质量浓度(0.5,1.0,1.5,2.0 g/L)、反应时间(4,8,12,24 h)、反应pH值(7.0,7.4,8.0)分为不同实验组。 结果与结论：茚三酮显示精氨酸甘氨酸天冬氨酸多肽可很好的交联到猪主动脉瓣去细胞支架材料,最佳反应条件为：室温、1.5 g/L精氨酸甘氨酸天冬氨酸、pH 7.4、持续振荡12 h。提示利用YGRGDSP多肽对猪主动脉瓣去细胞支架材料进行表面修饰可显著改善骨髓来源种子细胞的黏附性。     

叶酸分子靶向载顺铂磁性纳米药物制备及表征

背景：醛基化海藻酸钠具有良好的水溶性和组织相容性,利用其改性Fe3O4磁性纳米颗粒可增加表面活性和稳定性,叶酸的修饰可赋予载体分子靶向性。 目的：制备具有叶酸受体靶向及磁靶向的载顺铂磁性纳米药物(CDDP-FA-ASA-MNPs)。 方法：采用高碘酸钠氧化法制备醛基化海藻酸钠,叶酸的羧基经二环己基碳二亚胺和N-羟基琥珀酰亚胺活化后合成FA与双端氨基聚乙二醇的耦连产物FA-PEG,化学共沉淀法制备Fe3O4,海藻酸钠侧链含有大量羧基,85 ℃下与Fe3O4纳米颗粒表面的羟基形成化学键结合,然后通过雪夫氏碱将FA-PEG与醛基化海藻酸钠相连接,最后根据配位络合的原理,顺铂分子中的-Cl被海藻酸钠的羧基取代,形成稳定的叶酸和醛基化海藻酸钠改性载顺铂磁性纳米复合物。 结果与结论：所制备的磁性纳米药物呈颗粒状,稳定分散于水溶液中,Fe3O4磁核平均粒径为(8.116±0.24) nm,流体力学直径为(110.9±1.7) nm,zeta电位为(-26.45±1.26) mV,最大饱和磁化强度为56.2 emu/g,顺铂包封率为(49.05±1.58)%,载药量为(14.31±0.49)%。体外实验证实,叶酸分子靶向载顺铂磁性纳米药物能被叶酸受体表达阳性的鼻咽癌细胞HNE-1和喉癌细胞Hep-2选择性摄取,而叶酸受体表达阴性的鼻咽癌细胞CNE-2则不摄取。提示所制备的CDDP-FA-ASA-MNPs具有良好的水溶性和稳定性,能被叶酸受体表达阳性的鼻咽癌和喉癌细胞摄取。     

Development and use of iron oxide nanoparticles (Part 1): Synthesis of iron oxide nanoparticles for MRI

Contrast agents, such as iron oxide, enhance MR images by altering the relaxation times of tissues in which the agent is present. They can also be used to label targeted molecular imaging probes. Unfortunately, no molecular imaging probe is currently available on the clinical MRI market. A promising platform for MRI contrast agent development is nanotechnology, where superparamagnetic iron oxide nanoparticles (SPIONS) are tailored for MR contrast enhancement, and/or for molecular imaging. SPIONs can be produced using a range of methods and the choice of method will be influenced by the characteristics most important for a particular application. In addition, the ability to attach molecular markers to SPIONS heralds their application in molecular imaging.There are many reviews on SPION synthesis for MRI; however, these tend to be targeted to a chemistry audience. The development of MRI contrast agents attracts experienced researchers from many fields including some researchers with little knowledge of medical imaging or MRI. This situation presents medical radiation practitioners with opportunities for involvement, collaboration or leadership in research depending on their level of commitment and their ability to learn. Medical radiation practitioners already possess a large portion of the understanding, knowledge and skills necessary for involvement in MRI development and molecular imaging. Their expertise in imaging technology, patient care and radiation safety provides them with skills that are directly applicable to research on the development and application of SPIONs and MRI.In this paper we argue that MRI SPIONs, currently limited to major research centres, will have widespread clinical use in the future. We believe that knowledge about this growing area of research provides an opportunity for medical radiation practitioners to enhance their specialised expertise to ensure best practice in a truly multi-disciplinary environment. This review outlines how and why SPIONs can be synthesised and examines their characteristics and limitations in the context of MR imaging.     

基于MR分子成像的分子探针及其研究进展

MR分子成像可以利用MRI技术并借助对比剂的生化特征来直接或间接地反映目的基因的情况,其核心任务的关键在于分子探针的选用。本文介绍了分子探针在MRI技术中的重要性及MR分子成像对分子探针的要求,且着重阐述了MR分子成像中分子探针的种类及其应用进展情况。     

Detection of enzyme activity in orthotopic murine breast cancer by fluorescence lifetime imaging using a fluorescence resonance energy transfer-based molecular probe

Cancer-related enzyme activity can be detected noninvasively using activatable fluorescent molecular probes. In contrast to "always-on" fluorescent molecular probes, activatable probes are relatively nonfluorescent at the time of administration due to intramolecular fluorescence resonance energy transfer (FRET). Enzyme-mediated hydrolysis of peptide linkers results in reduced FRET and increase of fluorescence yield. Separation of signal from active and inactive probe can be difficult with conventional intensity-based fluorescence imaging. Fluorescence lifetime (FLT) measurement is an alternative method to detect changes in FRET. Thus, we investigate FLT imaging for in vivo detection of FRET-based molecular probe activation in an orthotopic breast cancer model. Indeed, the measured FLT of the enzyme-activatable molecular probe increases from 0.62 ns just after injection to 0.78 ns in tumor tissue after 4 h. A significant increase in FLT is not observed for an always-on targeted molecular probe with the same fluorescent reporter. These results show that FLT contrast is a powerful addition to preclinical imaging because it can report molecular activity in vivo due to changes in FRET. Fluorescence lifetime imaging exploits unique characteristics of fluorescent molecular probes that can be further translated into clinical applications, including noninvasive detection of cancer-related enzyme activity.     

量子点探针对人肝癌裸鼠模型的体内靶向成像研究

目的研究量子点标记靶向探针对人肝癌裸鼠模型的体内成像技术。方法将巯基乙酸修饰的水溶性量子点结合鼠抗人甲胎蛋白（AFP）单克隆抗体制备成水溶性量子点-AFP-Ab复合物探针。荧光、紫外光光谱分析及透射电镜研究其特性。通过直接免疫荧光法,用该复合物探针特异性识别肝癌细胞株HCCLM6 AFP抗原。将体外培养的肝癌细胞株HCCLM6通过皮下接种和尾静脉注射裸鼠分别建立人肝癌裸鼠模型和肺转移模型。尾静脉注射量子点-AFP-Ab探针,用蓝光二极管照射获得活体荧光成像;用掺Ti蓝宝石激光器照射,对肿瘤部位和正常部位进行光谱分析。取血清检测丙氨酸转氨酶、天冬氨酸转氨酶、尿素氮和肌苷水平。取裸鼠肝、脾、肾、肺、心和脑6种主要实质性器官行振荡切片,共聚焦显微镜观察,研究量子点-AFP-Ab探针在裸鼠体内的非特异性摄取。结果量子点-AFP-Ab复合物探针具有激发光谱宽、荧光强度高的特点,能特异性与肝癌细胞AFP抗原高亲和力结合,在体内能特异性靶向肿瘤组织进行活体成像,无明显急性毒性。光谱分析显示量子点-AFP-Ab复合物探针主要分布于肿瘤的外周部位,少数该探针被肝、脾和肺非特异性摄取。结论量子点-AFP-Ab复合物探针具有优良的光学特性和生物相容性,能够进行肝癌体内靶向成像,将有助于肝癌的分子靶向研究。     

动态荧光分子成像技术研究进展

动态荧光分子成像技术能够描述荧光分子探针在生物体内吸收、分布以及排出的完整过程,是一种可以对生物体的生理、病理过程进行连续监测的动态成像技术.这项技术具有无电离辐射、成像速度快、灵敏度及特异度高、费用低廉等优点,在基础医学及临床医学研究中具有广阔的应用前景.从系统、算法和应用3个方面对动态荧光分子成像技术的研究进展进行了综述.     

荧光分子成像的探针技术及其应用

近几年,随着生物和基因技术的发展,荧光探针的获取手段越来越丰富.荧光探针的发展使得荧光分子成像技术及其应用备受关注.借助于荧光探针,可以对目标分子、蛋白质、基因等特异性成像,从而实现分子、蛋白、基因等的精确定位与分析,进一步实现疾病的早期诊断与治疗.主要对荧光分子成像技术中用到的荧光探针技术以及在生物医学领域的应用进行概述.     

PEI protected aptamer molecular probes for contrast-enhanced in vivo cancer imaging

Aptamers have emerged as promising molecular probes for cancer diagnosis. However, their application for in?vivo cancer imaging remains limitation due to the poor stability in blood and the degradation by nucleases. In the present study, we generated PEI/aptamer molecular complexes for cancer imaging in?vivo by using deoxyribonuclease (DNase)-activatable fluorescence probes (DFProbes) to monitor DNA degradation. The results showed that the complexes with PEI at the N/P ratio from 3.8 to 15 effectively prevented the degradation of DFProbes both in?vitro and in?vivo. Moreover, PEI successfully protected TD05 aptamers from DNase degradation without affecting its specific recognition of Ramos cells. In tumor bearing mice, PEI/aptamer molecular complexes further demonstrated superior passive tumor targeting and extended circulation time as compared with free aptamer. Hence, the well-defined PEI/aptamer probe is a novel strategy to deliver targeted aptamer for tumor diagnosis and imaging in?vivo.     

量子点在乳腺癌研究中的应用进展

乳腺癌肿瘤标志物与乳腺癌生物学行为密切相关,是乳腺癌治疗的重要依据。免疫组织化学法是目前临床最常用的分子病理学检测方法,但它不能满足临床定量化和个体化治疗的需求。量子点具有优良的光学特性,量子点探针技术已成功用于乳腺癌分子成像与体内成像、药物转运机制研究、靶向治疗研究等,特别是乳腺癌标志物检测,对乳腺癌的分子靶向诊断和个体化治疗决策有重要指导价值,其应用前景广阔。     

Optical imaging of reporter gene expression using a positron-emission-tomography probe

Reporter gene∕reporter probe technology is one of the most important techniques in molecular imaging. Lately, many reporter gene∕reporter probe systems have been coupled to different imaging modalities such as positron emission tomography (PET) and optical imaging (OI). It has been recently found that OI techniques could be used to monitor radioactive tracers in vitro and in living subjects. In this study, we further demonstrate that a reporter gene∕nuclear reporter probe system [herpes simplex virus type-1 thymidine kinase (HSV1-tk) and 9-(4-(18)F-fluoro-3-[hydroxymethyl] butyl) guanine ([(18)F]FHBG)] could be successfully imaged by OI in vitro and in vivo. OI with radioactive reporter probes will facilitate and broaden the applications of reporter gene∕reporter probe techniques in medical research.     

The biocompatibility of quantum dot probes used for the targeted imaging of hepatocellular carcinoma metastasis

Semiconductor quantum dots (QDs) have several photo-physical advantages over organic dyes making them good markers in biomedical application. We used CdSe/ZnS QDs with maximum emission wavelength of 590nm (QD590) linked to alpha-fetoprotein (AFP) monoclonal antibody (Ab) to detect AFP in cytoplasm of human hepatocellular carcinoma (HCC) cell line HCCLM6. For the in vivo studies, we used QD-AFP-Ab probes for targeted imaging of human HCC xenograft growing in nude mice by injecting them into the tail vein. In addition, the cytotoxicity in vitro, the acute toxicity in vivo, the hemodynamics and tissue distribution of these probes were also investigated. The results in vitro and in vivo indicate that our QD-based probes have good stability, specificity and biocompatibility for ultrasensitive fluorescence imaging of molecular targets in our liver cancer model system.