一种示踪干细胞的磁共振-荧光双模成像探针

本文设计并合成了Gd基磁共振-荧光双模成像探针——Gd-DOTA-PEG-GA,通过电穿孔的方式标记人源间充质干细胞（hMSCs）.电穿孔标记诱导细胞将探针组装成团簇状纳米粒子进入细胞质,显著延长其与细胞结合的时间,并呈现出明显的T₂信号减弱效应,且信号减弱效应可以持续7天以上.在水溶液中,该探针的发射带集中在498 nm,并且荧光强度在一周内无明显衰减.该探针标记的细胞在荧光倒置显微镜下呈现绿色荧光.这些结果表明该探针可以作为磁共振-荧光双模成像探针用于干细胞示踪.     

新型Gd基T2造影剂的制备和应用

设计并合成了结构为TPP-Lys（Acp-DOTA-Gd）-COOH（简称Gd-DOTA-TPP）的小分子磁共振探针,通过电转染的方式用探针标记人源脐带间充质干细胞（hMSCs）.11.7 T磁共振成像（MRI）扫描结果表明,Gd-DOTA-TPP标记的hMSCs在细胞内Gd含量为9×10⁹ Gd/cell时,T₂加权信号强度即可低至背景信号强度,呈现较强暗信号.将Gd-DOTA-TPP标记的hMSCs移植入小鼠脑室,可明显提高移植干细胞在MRI设备上的检测灵敏度,检测限可低至10³个细胞.     

基于微球透镜的任选区高分辨光学显微成像新方法研究

提出和发展了基于毛细管-微球组合探针的任选区、 高分辨显微成像新方法. 建立了微球显微成像的物理模型, 利用成像理论,推导出微球成像的放大倍率; 采用3.0, 4.4, 5.6, 7.5, 10.0 μm等不同直径的SiO₂微球, 对未经刻录的DVD光盘进行了微球显微成像实验, 可以观察到DVD光盘的微纳米结构被明显放大且对比度显著提高, 与理论计算结果相符合; 采用毛细管微探针操纵微球的方法, 实现了基于微球透镜阵列的样品微纳米结构的高分辨显微成像; 在此基础上, 进一步将毛细管微探针与微球组合, 制备出毛细管-微球组合型探针, 首次实现了基于微球透镜的样品任意区域高分辨显微成像.     

基于PS@Ag纳米探针和Si@Ag阵列基底的表面增强拉曼散射特性的肿瘤标志物免疫检测

基于Ag包覆聚苯乙烯球(PS@Ag)纳米探针和Ag覆盖硅金字塔结构(Si@Ag)阵列基底构建"三明治"免疫结构,开展表面增强拉曼散射(SERS)特性研究,实现了肝癌肿瘤标志物甲胎蛋白(AFP)的高灵敏、高特异性的检测.通过硝酸银原位还原生成PS@Ag纳米粒子,再依次链接4-巯基苯甲酸(4-MBA)及甲胎蛋白抗体(Anti-AFP)制备得到PS@Ag免疫探针.采用Langmiur-Bloggt膜技术、等离子体刻蚀和湿法刻蚀技术,以PS球阵列为模版,刻蚀大面积硅金字塔结构,再依次沉积Ag膜和链接Anti-AFP制备得到免疫基底.结果表明,基于"三明治"免疫结构的SERS检测方案具有高灵敏度(检测极限为1.75fg·mL~(-1))和宽的动态范围(2fg·mL~(-1)～200ng·mL~(-1)).此外,对临床人体血清样品进行SERS免疫检测,得到了与化学免疫发光法一致的结果,而且具有更高的灵敏度,可应用于肝癌的早期检测与诊断.     

链接琥珀酰亚胺的线性硝酮的合成与ESR研究

该文设计并合成一种新的线性硝酮自由基捕获探针DSC-PBN(N-(4-(((2,5-dioxopy-rrolidin-1-yloxy)-carbonyloxy)methyl)benzylidene)-2-methylpropan-2-N-oxide),并采用UV、MS、1H NMR等一系列手段表征分子结构.进一步通过自由基捕获实验显示,DSC-PBN可与多种活泼自由基反应生成稳定的氮氧自由基加合物,且所得ESR谱图易于解析和分辨.由于DSC-PBN自由基捕获探针链接琥珀酰亚胺基团,可望通过与蛋白质(或多肽)N端的共价键合而应用于生物体系自由基分析.     

叶酸受体靶向肿瘤细胞纳米探针的制备及其光谱分析

叶酸受体在正常组织上表达很少,而在上皮源性的恶性肿瘤细胞膜表面高度表达。文中以叶酸为稳定剂和包裹剂,以硼氢化钠为还原剂,简单快捷地制备出叶酸包裹的纳米金粒子(folic acid protected gold nanoparticles,FA-GNPs)作为靶向肿瘤探针。紫外-可见吸收光谱测量,透射电镜成像、X射线光电子能谱分析以及细胞结合试验都表明,这种纳米探针粒径分布在3～5nm之间,体系均一、稳定,而且在高盐环境(3.5%NaCl溶液)和高速离心(25 000r.min-1)下均不会发生聚沉,在肿瘤细胞检测等领域具有应用潜力。     

巯基琥珀酸包被的CdTe量子点的制备及其在细胞标记中的应用

以巯基琥珀酸(MSA)作为稳定剂,在水溶液中合成稳定的CdTe纳米量子点,用紫外-可见荧光分光光度和荧光光谱方法研究了CdTe量子点的发光特性.并将其与鼠抗人AFP抗体连接制备水溶性CdTe-AFP复合物探针,对人肝癌细胞进行标记和成像.结果表明所制备的CdTe-AFP复合物探针对人肝癌细胞成像清晰,在生物医学领域具有重要的应用价值.     

一种基于苯并噻唑的长波长双响应性荧光探针对粘度与H_2O_2的检测

H_2O_2是一种常见的生物活性小分子,其在细胞增殖,炎症反应,细胞信号传输等过程中都起着重要的作用。细胞粘度是一项重要的生理微环境参数,其为细胞是否正常运转的关键指标。研究还表明,一些重大的生理疾病与细胞组织的粘度及过氧化氢浓度异常均有着密切的关联,如阿尔茨海默病、癌症。因此开发能有效同时检测H_2O_2及粘度的分析方法对揭示相关生理病理机制及重大疾病的诊断有着重要的意义。研制了一种能有效检测H_2O_2与粘度的双响应型荧光探针(1)。由于存在扭曲分子内电荷转移(TICT)的猝灭效应,探针(1)几乎不具有荧光发射特性。而随着环境体系粘度的增高, TICT效应被抑制,探针(1)呈现出了强的荧光发射,且发射峰位于近红外波段处(680 nm)。随着粘度从1.996 cp增至851.8 cp,探针的荧光强度增幅达到了85倍。探针还能对H_2O_2产生灵敏的荧光响应,发射峰位置在590 nm处。响应原理为H_2O_2能与探针中的苯硼酸基团反应使探针脱除掉与吡啶氮原子相连的亚甲基苯硼酸,从而减弱了探针分子中的TICT效应以及分子内电荷转移(ICT)效应,因此探针溶液荧光发射显著增强且探针溶液的紫外光谱发生了明显的蓝移(吸收峰从540 nm移至460 nm),对应溶液颜色从红色变为黄色。荧光光谱测试表明探针(1)对H_2O_2的检测具有高的选择性与灵敏度,探针体系在590 nm处的荧光强度与H_2O_2的浓度呈良好的线性关系,线性范围为0～25μmol·L~(-1),根据IUPAC的3σ法计算得出检测限为0.34μmol·L~(-1)。此外细胞荧光成像实验表明探针(1)具有较好的生物相容性及细胞膜通透性,且能实现细胞内H_2O_2的成像分析。     

二溴羟基卟啉与核酸相互作用的光谱行为研究

研究了meso-4(3,5-二溴-4-羟基苯基)卟啉(T(DBHP)P)与小牛胸腺DNA(ct DNA)相互作用的光谱行为,探讨了以T(DBHP)P作为光谱探针测定核酸的最佳条件及作用机理.在pH 4.92 HAc-NaAc缓冲液中,T(DBHP)P在最大吸收波长425 nm处的吸收峰强度显著下降,且下降程度与ct DNA含量呈线性关系,ct DNA含量在0.20～1.80 μg·mL-1范围内符合比尔定律,检出限为0.024 μg·mL-1.实验中发现Tween-80微乳液的加入能显著增加体系的灵敏度.同时,用摩尔比法测定了DNA与卟啉的结合数为21,并初步探讨了反应机理.     

N-乙基丙酰胺在高浓度盐溶液中的超快二维红外光谱

β-多肽是由β-氨基酸组成的一类非天然多肽,具有丰富的二级结构。N-乙基丙酰胺(NEPA)是研究β-多肽骨架结构动力学的重要模型分子。解析NEPA在不同溶液环境下的超快结构变化,对研究β-多肽在不同条件下的结构分布及动态结构变化过程有着重要意义。我们选取酰胺-Ⅰ带为探针,利用傅里叶变换红外(FTIR)光谱和超快二维红外(2DIR)光谱手段,研究了NEPA分别与高浓度(4.5mol·L~(-1))下的CaCl_2和MgCl_2之间的作用机制。本研究旨在阐明离子与NEPA酰胺单元的相互作用,为解释β-多肽在复杂溶液环境中的结构动力学提供实验依据。     

一种肝脏类生物相容性氨基酸共聚物磁共振成像造影剂

一种新型的以天门冬氨酸-苯丙氨酸共聚物为载体的大分子生物相容性材料(AP-EDA-DOTA-Gd)被制备出来作为磁共振成像造影剂．首先合成了天门冬氨酸-苯丙
氨酸共聚物,之后利用乙二胺将1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸(DOTA)连接到共聚物上,最后将钆离子通过配位的作用方式连接到DOTA 上,最终得到大分子AP-EDA-DOTA-Gd．体外溶血性试验表明AP-EDA-DOTA-Gd 具有较好的血液相容性．在pH = 5.5 的组织蛋白酶B 的磷酸缓冲液中,AP-EDA-DOTA-Gd 能够降解．APEDA-DOTA-Gd 的体外弛豫效率(15.95 mmol^–1?L?s^–1)为目前临床应用的Gd-DOTA (5.59mmol^–1?L?s^–1)的2.9 倍．大鼠肝脏成像实验结果表明,AP-EDA-DOTA-Gd 对于肝组织的成像增强对比度为63.5±6.1%远高于Gd-DOTA (24.2±2.9%)．     

壳聚糖修饰金属卟啉的制备及磁共振成像性能

合成了窄分子量分布低聚壳聚糖(CS₂₀)修饰的四(4-羧基苯基)锰(Ⅱ)卟啉(Mn-TCPP)功能配合物(Mn-TCPP-CS₂₀)作为一种潜在的磁共振成像(MRI)造影剂。发现该锰基卟啉-壳聚糖配合物(Mn-TCPP-CS₂₀)有良好的水溶性和分子结构稳定性。通过红外(FTIR)、紫外(UV-Vis)、质谱(MS)及电感耦合等离子体发射仪(ICP-AES)对其结构进行了表征。表明,低聚壳聚糖CS₂₀通过酰胺键与Mn-TCPP共价链接。初步研究了功能配合物Mn-TCPP-CS₂₀作为潜在的MRI造影剂的体外弛豫性能,发现其纵向弛豫率r₁ (6.11 mmol-1·l·s-1)高于商用的MRI造影剂Gd-DTPA (r₁=3.59 mmol-1·l·s-1),且在同等条件下体外成像效果更优。Mn-TCPP-CS₂₀可作为潜在的具有组织靶向性的MRI造影剂。     

Variations in Toxic Metal Levels of Two Fish Species,Pomatomus saltatrix and Dicentrarchus labrax,and Risk Estimation for Children简

The concentrations of five toxic metals were monthly determined in two fish species, obtained from fish markets in Turkey during 2010—2011. For the determinations, AAS and ICP-AES were used. The obtained lead concentrations for all studied Pomatomus saltatrix (mean 635 μg·kg-1) and Dicentrarchus labrax (mean 463 μg·kg-1) samples were found to be significantly higher than the maximum allowances concentration (MAC) of 300 μg·kg-1. Mean chromium (324 μg·kg-1) and Cu (940 μg·kg-1) concentrations in Pomatomus saltatrix were higher than in Dicentrarchus labrax (268 μg Cr·kg-1 and 600 μg Cu·kg-1) while Ni in Pomatomus saltatrix (216 μg·kg-1) was lower in Dicentrarchus labrax (291 μg·kg-1). The estimated non-carcinogenic and carcinogenic health risks by the Target Hazard Quotient and target carcinogenic risk indicate that there are no sytemic effects, and the risk of developing cancer over a human lifetime is between 2～9 in 1 000 000.     

Synthetic and biogenic magnetite nanoparticles for tracking of stem cells and dendritic cells

Accurate delivery of cells to target organs is critical for success of cell-based therapies with stem cells or immune cells such as antigen-presenting dendritic cells (DC). Labeling with contrast agents before implantation provides a powerful means for monitoring cellular migration using magnetic resonance imaging (MRI). In this study, we investigated the uptake of fully synthesized or bacterial magnetic nanoparticles (MNPs) into hematopoietic Flt3⁺ stem cells and DC from mouse bone marrow. We show that (i) uptake of both synthetic and biogenic nanoparticles into cells endow magnetic activity and (ii) low numbers of MNP-loaded cells are readily detected by MRI.     

活性层厚度对体异质结聚合物太阳能电池性能的影响

制备了MEH-PPV(poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene])和PCBM (1-(3-mehyloxycarbonyl)propy1-phenyl[6,6]C₆₁)共混体系的聚合物太阳能电池。通过改变MEH-PPV∶PCBM(质量比为1∶4)混合溶液的浓度及旋涂时的转速来改变活性层的厚度,研究了器件性能随活性层厚度的变化。当旋涂速率小于4 000 r·min-1时随着厚度的减小,开路电压没有明显的变化,基本在0.8 V左右,但短路电流呈现单调上升的趋势,填充因子略有下降。当旋涂速率大于5 000 r·min-1时,开路电压和短路电流都开始下降。其中,开路电压从5 000 r·min-1时的0.78 V下降到8 000 r·min-1时的0.67 V,短路电流更是从5 000 r·min-1时的3.96 mA·cm-2下降到8 000 r·min-1 时的1.76 mA·cm-2。短路电流受光吸收和载流子传输两方面的共同影响,而活性层厚度的变化使得这两方面的影响产生相悖的效果。活性层越厚,光生激子数越多,但同时内建电场变弱,而且激子解离后得到的载流子传输到相应电极的距离越长,载流子被电极收集的概率减小。开路电压的降低则源于激子在MEH-PPV和PCBM与相应电极界面处解离比重的增加。     

Synthesis of amino-group functionalized superparamagnetic iron oxide nanoparticles and applications as biomedical labeling probes

Superparamagnetic iron oxide (SPIO) nanoparticles were synthesized by coprecipitation technique and further functionalized with amino-group to obtain amino-group functionalized (amino-SPIO) nanoparticles. The X-ray diffraction results reveal the structure of amino-SPIO nanoparticles, from which the average iron core diameter is approximately 10 nm by calculation; while Zetasizer reveals their hydrodynamic diameter are mainly distributed in the range of 40?C60 nm. These nanoparticles can be taken up by liver tissue, resulting in dramatically darkening of liver tissue under T2-magnetic resonance imaging (MRI). The spin?Cspin relaxivity coefficient of these nanoparticles is 179.20 mM^?1 s^?1 in a 1.5 T magnetic resonance system. In addition, amino-SPIO nanoparticles were conjugated to Tat (FITC) peptide and incubated with neural stem cells in vitro, the authors can detect the positive-labeling (labeled) neural stem cells showing green fluorescence, which indicates Tat (FITC) peptide-derivated amino-SPIO nanoparticles are able to enter cells. Furthermore, it was also find significant negative T2 contrast enhancement when compared with the non-nanoparticles-labeled neural stem cells in T2-weighted MRI. The amino-SPIO nanoparticles show promising potential as a new type of labeling probes, which can be used in magnetic resonance-enhanced imaging and fluorescence diagnosis.     

Multifunctional iron platinum stealth immunomicelles: targeted detection of human prostate cancer cells using both fluorescence and magnetic resonance imaging

Superparamagnetic iron oxide nanoparticles (SPIONs) are the most common type of contrast agents used in contrast agent-enhanced magnetic resonance imaging (MRI). Still, there is a great deal of room for improvement, and nanoparticles with increased MRI relaxivities are needed to increase the contrast enhancement in MRI applied to various medical conditions including cancer. We report the synthesis of superparamagnetic iron platinum nanoparticles (SIPPs) and subsequent encapsulation using PEGylated phospholipids to create stealth immunomicelles (DSPE-SIPPs) that can be specifically targeted to human prostate cancer cell lines and detected using both MRI and fluorescence imaging. SIPP cores and DSPE-SIPPs were 8.5 ± 1.6 nm and 42.9 ± 8.2 nm in diameter, respectively, and the SIPPs had a magnetic moment of 120 A m²/kg iron. J591, a monoclonal antibody against prostate specific membrane antigen (PSMA), was conjugated to the DSPE-SIPPs (J591-DSPE-SIPPs), and specific targeting of J591-DSPE-SIPPs to PSMA-expressing human prostate cancer cell lines was demonstrated using fluorescence confocal microscopy. The transverse relaxivity of the DSPE-SIPPs, measured at 4.7 Tesla, was 300.6 ± 8.5 s^?1 mM^?1, which is 13-fold better than commercially available SPIONs (23.8 ± 6.9 s^?1 mM^?1) and ~3-fold better than reported relaxivities for Feridex^® and Resovist^®. Our data suggest that J591-DSPE-SIPPs specifically target human prostate cancer cells in vitro, are superior contrast agents in T ₂-weighted MRI, and can be detected using fluorescence imaging. To our knowledge, this is the first report on the synthesis of multifunctional SIPP micelles and using SIPPs for the specific detection of prostate cancer.     

Molecular imaging contrast media for visualization of liver function

Background and Aims

Diagnosis of liver disease has improved because of progress in imaging technology. Among the imaging methods, magnetic resonance imaging (MRI) has the advantage of a lack of radiation exposure, but the basis of the method (imaging of hydrogen atoms in water molecules) makes it hard to detect changes in tissue or the location of the diseased tissue in the liver. The aims of this study are to develop new contrast media for visualization of functional changes in the liver and to check the effectiveness of the media.

Methods

We developed a new molecular imaging contrast media that targets the asialoglycoprotein receptor (ASGP-R), a membrane protein that is specific to hepatocytes. We first checked the contrast media diameter and the cytotoxicity. Next, we examined the interaction of the media with ASGP-R through observation of fluorescein isothiocyanate (FITC)-labeled molecular imaging contrast media bound to normal hepatocellular ASGP-R using confocal laser scanning microscopy. Finally, we used MRI to observe hepatocyte interactions with the molecular imaging contrast media.

Results

The contrast media forms a nanoparticle of about 30 nm diameter in aqueous solution and the cytotoxicity is low. In vitro, the media has high specificity for ASGP-R in normal rat hepatocyte RLN-8 cells and this interaction was blocked by lactose (which has a similar molecular structure to that of galactose) and by an anti-ASGP-R antibody. The contrast media markedly enhanced T1-weighted images in MRI of normal rat hepatocytes compared to the signal strength for rat liver cancer cells.

Conclusions

We have shown that our new contrast media for molecular imaging of hepatocytes by MRI is effective in vitro.