量子点成像的新研究进展

量子点(又称纳米荧光颗粒)在生物学研究中特别是在生物医学成像方面的应用,已引起广泛关注。通过荧光成像可观察量子点标记分子与其靶标的相互作用,实时观测其在活细胞及活体中的运行轨迹,实现对细胞水平及在体层次的研究。本文综述了近两年量子点在光学成像中应用的新进展,展望了其应用前景。     

面向持续观测的静止轨道高分辨率光学成像卫星应用模式设计与分析

为充分发挥静止轨道高分辨率光学成像卫星在持续观测应用方面的作用,在分析静止轨道卫星轨道特点、成像特点、成像优势的基础上,充分利用静止轨道高分辨率光学成像卫星任务响应速度快、重复探测频率高、姿态机动灵活等特点,提出了一种适合持续观测的星地一体应用模式,该模式综合考虑平时和应急两种态势,规划了5种具体的观测模式,可以为提高静止轨道高分辨率光学遥感卫星的规划和应用提供依据。     

单细胞成像分析研究进展

本文综述了近年来单细胞成像分析方法的研究进展。重点讨论了图像细胞光度测量、荧光显微成像、红外(近红外)与拉曼显微成像、磁共振成像和扫描探针显微镜成像等技术,并展望了单细胞成像的发展前景。     

核酸荧光探针在单细胞成像中的应用研究

单细胞成像研究技术具有观测定位精准、独特的时间和空间分辨率高等特点,成为分子水平上准确、实时、原位监测细胞内生物活性物质信号变化及观测细胞形态的重要手段。在进行单细胞成像研究时,细胞内大多数生物活性物质自身无法产生易被仪器或肉眼所捕获的信号,通常需要使用生物探针进入细胞内特异性识别生物活性物质。生物探针与特定的生物活性物质结合,形成稳定的复合物,产生相应信号变化。通过监测生物探针信号变化,实现对细胞内生物活性物质准确、实时、原位监测。生物探针的响应信号有多种,其中荧光信号不仅具有直观、操作简单、选择性好、灵敏度高、无需参比、不受电磁场的影响、可远程实时在线自动监测等特性,还具备对细胞进行静态观察、对细胞内分子动力学进行动态监测、对亚细胞结构进行定位和对蛋白质分子的相互作用进行研究等优点,在细胞成像技术研究中具有重要地位。本文综述了近五年来核酸荧光探针在单细胞成像中的应用研究进展,讨论了存在的问题,对发展方向进行了展望。     

常压敞开式质谱成像技术及其应用

质谱成像将质谱的离子扫描技术与成像处理软件相结合,能有效地对分子的空间分布信息进行检测和成像;常压敞开式离子化技术的出现,为质谱成像提供了新的发展方向。本文对常压敞开式质谱成像技术及其应用进行了综述。     

光热显微术:基于光吸收的单分子成像技术

光热显微术是近年来获得广泛关注和长足发展的一种新型光学显微成像技术,能够实现单个纳米粒子甚至单分子的免标记光学成像。其成像原理是利用先进的光学方法探测单分子或单纳米粒子吸收特定波长激发光后所产生的局域温度和介质折射率的微小变化,从而定量研究观测对象的光热特性。由于无辐射弛豫是激发态分子回到基态的优势过程,分子的光热特性相比于荧光特性更具有普遍意义。凭借无需标记、高灵敏度和信号稳定等优点,近十年来,关于单分子和单纳米粒子的光热显微成像研究不断取得突破,并在纳米科学和生命科学等领域获得越来越多的发展和应用,展现出了蓬勃的生命力和良好的发展前景。本文重点综述了光热显微技术的成像原理、发展历程、技术特色以及系统优化方法,列举了光热成像在活细胞研究和生物学领域的应用,最后总结了光热成像的优缺点并分析其主要面临的挑战以及未来的发展趋势,希望吸引更多的研究人员加入到这一新技术的研究队伍中来。     

质谱成像分析技术、方法与应用进展

质谱成像技术作为分子成像及质谱领域的研究前沿和热点,近几年受到高度关注并得到迅速发展.本文针对质谱成像技术、方法及其应用的新进展进行了综述与展望,介绍了中国学者近几年在质谱成像分析新技术及其应用方面取得的重要进展.     

医学成像光谱技术研究进展

从成像光谱技术的发展概况出发,综述了医学成像光谱技术的研究现状和最新进展,对现有的医学成像光谱仪按照类别进行分析,对其在生物医学领域应用概况和应用前景进行了探讨.对医学成像光谱技术的发展趋势和今后研究需要解决的问题进行了评述.     

聚乙烯亚胺修饰BaGdF_5纳米粒子的制备及CT/MR双模成像性能

通过微波辅助的溶剂热法制备了聚乙烯亚胺修饰BaGdF_5纳米粒子,并对其进行了表征、毒性评估、计算机X射线断层扫描(CT)成像及磁共振(MR)成像分析.透射电子显微镜(TEM)观测结果表明,该纳米粒子呈球形,表面光滑,分布均匀,粒径约30 nm.MTT结果表明,该纳米粒子具有较低的细胞毒性;小鼠各器官的组织病理学结果表明,该纳米粒子具有较低的体内毒性;体外成像结果表明,该纳米粒子具有较好的CT成像及T1加权的MR成像能力;小鼠体内成像结果表明,该纳米粒子具有应用于肝脏双模态成像的潜力.     

太阳CO 4.6微米红外成像观测

太阳红外光谱中蕴含着丰富的物理信息,其中CO 4.6μm波段是具有代表性的分子谱带,其形成于温度极小区附近,对研究太阳物理具有极其重要的意义。为获得CO 4.6μm波段太阳单色像,本文建立了一套全反射太阳红外成像观测系统。该系统采用定天镜跟踪引光,通过成像反射镜将太阳成像于3~5μm波段红外相机的焦平面上,该相机采用的是国产HgCdTe焦平面阵列器件。同时,为提高信噪比,提出了一种有效计算平场提取观测目标的方法,并利用该方法获得了CO 4.6μm波段的太阳单色像。     

In Situ Scatheless Cell Detachment Reveals Correlation between Adhesion Strength and Viability at Single‐Cell Resolution

Single‐cell biology provides insights into some of the most fundamental processes in biology and promotes the understanding of life's mysteries. As the technologies to study single‐cells expand, they will require sophisticated analytical tools to make sense of various behaviors and components of single‐cells as well as their relations in the adherent tissue culture. In this paper, we revealed cell heterogeneity and uncovered the connections between cell adhesion strength and cell viability at single‐cell resolution by extracting single adherent cells of interest from a standard tissue culture by using a microfluidic chip‐based live single‐cell extractor (LSCE). We believe that this method will provide a valuable new tool for single‐cell biology.     

单细胞分析中的荧光标记化学*

细胞内组分复杂、含量低,因此测定单细胞内化学组分的分析方法必须具有灵敏度高、选择性好和分辨率高的特点。高灵敏度的荧光检测技术是单细胞分析中应用最多的检测方法之一。但是细胞内绝大部分物质其天然态是没有荧光的,且由于细胞膜的阻碍,衍生试剂不能自由地进入细胞内。为了使衍生试剂透过细胞膜标记细胞内待测物质而不引起显著的稀释效应,已进行了大量的研究工作。本文综述了在单细胞分析中常用的荧光标记方法,包括细胞作为微反应器的衍生法,借助于脂质体与聚乙二醇（PEG）等增加细胞膜通透性的衍生方法和在毛细管/芯片毛细管电泳分析单细胞时柱上衍生和柱后衍生法以及量子点的标记法等。对这些方法的原理、特点和在单细胞分析中的应用也做了较为详细的阐述。     

Design and fabrication of cell alignment device based on electrolytically-generated air bubbles, and its practical realization using polystyrene microbeads

For future medical diagnostics and drug screening, chip-based single cell analysis based on a micro-electro-mechanical system (MEMS) technology will be essential. Chip-based single cell analysis enables to perform exhaustive analysis of huge numbers of sample cells, reducing sample volume and analysis time and lowering the costs. However, the previously reported chip-based single cell analysis has some disadvantages of cell alignment, such as troublesome sample handling and long cell alignment time onto the chip. In this study, a cell alignment method and device based on electrically-generated air bubbles is presented. For practical realization, the cell alignment was carried out using microbeads. With this technique, the chip-based single cell analysis will be more simplified for medical and drug delivery applications.     

Short peptides enhance single cell adhesion and viability on microarrays

Single cell patterning holds important implications for biology, biochemistry, biotechnology, medicine, and bioinformatics. The challenge for single cell patterning is to produce small islands hosting only single cells and retaining their viability for a prolonged period of time. This study demonstrated a surface engineering approach that uses a covalently bound short peptide as a mediator to pattern cells with improved single cell adhesion and prolonged cellular viability on gold patterned SiO2 substrates. The underlying hypothesis is that cell adhesion is regulated by the type, availability, and stability of effective cell adhesion peptides, and thus covalently bound short peptides would promote cell spreading and, thus, single cell adhesion and viability. The effectiveness of this approach and the underlying mechanism for the increased probability of single cell adhesion and prolonged cell viability by short peptides were studied by comparing cellular behavior of human umbilical cord vein endothelial cells on three model surfaces whose gold electrodes were immobilized with fibronectin, physically adsorbed Arg-Glu-Asp-Val-Tyr, and covalently bound Lys-Arg-Glu-Asp-Val-Tyr, respectively. The surface chemistry and binding properties were characterized by reflectance Fourier transform infrared spectroscopy. Both short peptides were superior to fibronectin in producing adhesion of only single cells, whereas the covalently bound peptide also reduced apoptosis and necrosis of adhered cells. Controlling cell spreading by peptide binding domains to regulate apoptosis and viability represents a fundamental mechanism in cell-materials interaction and provides an effective strategy in engineering arrays of single cells.     

Hadamard变换显微图象分析III. 单细胞内DNA,RNA和蛋白质的 分析

本文用自制的Hadamard变换显微图象分析仪分析了AO和FITC染色的单细胞的荧光光谱,用该仪器获取了单个洋葱细胞核内DNA的分布图象,并在535nm处分别测定了AQ染色的鸡红血细胞及洋葱表皮细胞核的荧光强度。所得结果与生物学结果吻合,显示了该仪器在单细胞试样分析中的应用价值。     

Differential interference contrast microscopy for real-time dynamics and manipulation of single cells in microchannels

Nomarski differential interference contrast (DIC) microscopy was used for real-time dynamics of intact single cells in various microchannels for adaptation to microfluidic chip application. The cheek cell was chosen as a model, single cell and the dynamics was measured at the microchannels. The image resolution of single cell was shaper and more distinct in DIC than in conventional microscopy. The individual single living cells were also manipulated by both hydrodynamic and electrokinetic flow-driving forces at the microchannels. The DIC contrast was enhanced according to the order of round-, square-, and rectangle-type microchannels. The velocity of the single living cell was consistently increased with increasing electric field strength and pH. However, the velocity of cell was decreased with increasing run buffer concentration. The driving direction of the individual single cell was simply controlled by changing the polarity of the applied voltage and the electric field strength. The cells were consistently manipulated in the microchannel under the co-application of the low electric field of 2.44 V/cm, instead of the solo application of the hydrodynamic force.     

A microfluidic array with cellular valving for single cell co-culture

We present a highly parallel microfluidic approach for contacting single cell pairs. The approach combines a differential fluidic resistance trapping method with a novel cellular valving principle for homotypic and heterotypic single cell co-culturing. Differential fluidic resistance was used for sequential single cell arraying, with the adhesion and flattening of viable cells within the microstructured environment acting to produce valves in the open state. Reversal of the flow was used for the sequential single cell arraying of the second cell type. Plasma stencilling, along the linear path of least resistance, was required to confine the cells within the trap regions. Prime flow conditions with minimal shear stress were identified for highly efficient cell arraying (～99%) and long term cell culture. Larger trap dimensions enabled the highest levels of cell pairing (～70%). The single cell co-cultures were in close proximity for the formation of connexon structures and the study of contact modes of communication. The research further highlights the possibility of using the natural behaviour of cells as the working principle behind responsive microfluidic elements.     

Dielectrophoretic trapping of single leukemic cells using the conventional and compact optical measurement systems

Here, we report a microfluidic same‐single‐cell analysis to study the inhibition of multidrug resistance due to drug efflux on single leukemic cells. Drug efflux inhibition was investigated in the microfluidic chip using two different fluorescence detection systems, namely, a compact single‐cell bioanalyzer and the conventional optical detection system constructed from an inverted microscope and a microphotometer. More importantly, a compact signal generator was used to conduct dielectrophoretic cell trapping together with the compact SCB. By using the DEP force, a single acute myeloid leukemia cell was trapped in the cell retention structure of the chip. This allowed us to detect dye accumulation in the MDR leukemic cells in the presence of cyclosporine A (CsA). CsA and rhodamine 123 were used as the P‐glycoprotein inhibitor and fluorescent dye, respectively. The result showed that the Rh123 fluorescence signal in a single‐cell increased dramatically over its same‐cell control on both fluorescence detection systems due to the inhibition by CsA.     

微流控芯片电泳/电化学检测人单个肝癌细胞中的谷胱甘肽

采用微流控装置结合电化学检测研究了测定人单个血红细胞中谷胱甘肽(GSH)的方法。在该方法中,细胞的进样、定位、溶膜以及细胞中谷胱甘肽的转移和检测都在配有通道端安培检测器的双T形芯片中完成。单个细胞用液压导入到双T的交界面,在电泳缓冲液中毛地黄皂苷的作用下,细胞膜被穿孔。再施加直流电压,细胞被溶膜。释放出来的GSH被此直流电压电迁移至通道端并在Au/Hg电极上被检测。用校正曲线法可以定量测定单个细胞中的GSH。     

A Self‐Digitization Dielectrophoretic (SD‐DEP) Chip for High‐Efficiency Single‐Cell Capture,On‐Demand Compartmentalization,and Downstream Nucleic Acid Analysis

The design and fabrication of a self‐digitization dielectrophoretic (SD‐DEP) chip with simple components for single‐cell manipulation and downstream nucleic acid analysis is presented. The device employed the traditional DEP and insulator DEP to create the local electric field that is tailored to approximately the size of single cells, enabling highly efficient single‐cell capture. The multistep procedures of cell manipulation, compartmentalization, lysis, and analysis were performed in the integrated microdevice, consuming minimal reagents, minimizing contamination, decreasing lysate dilution, and increasing assay sensitivity. The platform developed here could be a promising and powerful tool in single‐cell research for precise medicine.