同步辐射红外显微光谱学和成像技术在分析化学中的应用

同步辐射红外显微光谱作为一种新兴的分析技术,一方面利用了红外光谱可以同时表征有机和/或无机、结晶和/或无定形样品的特点,另一方面充分发挥了同步辐射高亮度和高空间分辨率的特性,因此在对小样品或小样品区域的表征上具有传统红外光谱无法比拟的优势。经过20多年的发展,同步辐射红外显微光谱技术已被广泛地应用于多种分析化学领域并取得了丰硕的研究成果。本文总结了最近几年同步辐射红外显微光谱学和成像技术在文化遗产和考古学、地球和空间科学以及化学和高分子科学中的研究和应用进展。     

同步辐射红外光谱技术在生物医用领域的应用

同步辐射作为一种新型红外光源,具有光谱宽、亮度高、分辨率高的特性,在生命科学领域具有广泛的应用。随着同步红外显微镜成像技术的不断发展,同步辐射红外光谱技术可以在原位探测亚细胞级别的生物化学变化,并保留细胞的生命特征。通过对蛋白质、核酸、磷脂等成分的定性和定量分析,可以了解骨细胞、神经细胞的病变,癌变细胞的活动情况以及植物细胞的营养状况等。同时,同步辐射红外光谱技术的应用范围正在不断扩展,其在药物释放的检测和生物化学过程的监控等方面也具有相当的应用前景。此外,在生物分子的分子间振动能级所处的远红外区,同步辐射红外光谱相比于常规红外光谱具有较高的信噪比。     

同步辐射显微红外光谱法应用于杜仲的研究

同步辐射显微红外光谱具有高亮度、高信噪比等优势.应用同步辐射显微红外光谱对于中药进行研究,可以进行微区分析,从而更加深入了解中药的组成.应用同步辐射显微红外光谱对于杜仲的冰冻切片进行研究,采集不同微区的一系列红外光谱;同时对选定区域进行化学成像,进一步研究该区域中化学组成的分布,从而对于杜仲红外光谱中各个峰的归属有深入...     

傅里叶变换红外光谱新技术与新发展

傅里叶变换红外光谱联用技术 气相色谱(GC)与液相色谱(LC)是分离复杂混合物的有效方法,但仅靠保留指数定性分析未知物或未知组分始终存在着许多困难。而傅里叶变换红外光谱(FTIR)作为重要的结构测定手段,能提供许多色谱难以得到的结构信息,但它要求所分析的样品尽可能简单、纯净,而不能是复杂的混合物。因此,将色谱技术的优良分离能力与红外光谱技术独特的结构鉴别能力相结合,即两种方法的联用就可以达到取长补短的效果,无疑是一种具有很高实用价值的分离鉴别手段。例如GC/FTIR联用技     

同步辐射X射线成像技术在纳米探针细胞成像中的应用

纳米探针在肿瘤的高灵敏成像和高效治疗可视化方面具有重要的应用前景.通过细胞原位成像技术揭示纳米探针与细胞间的相互作用将为其临床应用奠定生物学基础.同步辐射X射线成像技术是研究纳米探针细胞原位摄取、胞内代谢及构效关系的重要方法.本文系统总结了基于同步辐射光源X射线成像技术在纳米探针细胞原位成像方面的研究进展,包括纳米探针的细胞原位成像、亚细胞结构原位成像、细胞原位价态分析、细胞原位定量成像以及细胞原位三维成像.此外,本文还对可用于纳米探针细胞成像的X射线成像技术的发展趋势进行了探讨.     

关于宫颈癌变细胞红外光谱测定方法的研究

提出了一种测定癌变细胞的新方法，利用高分辨傅里叶变换红外光谱（ＦＴＩＲ），对正常人的细胞和千余名宫颈癌患者的细胞进行了对比研究，初步得出该法能在分子水平上揭示出肿瘤细胞与正常细胞的明显差别，并且通过谱图解析，可直接阐明引起谱图变化的主要原因、细胞癌变的可能机理，从而对病程进行预测，为肿瘤疾病的早期诊断展现了良好的前景。     

红外光谱法研究苯胺和环氧丙烷的共聚机理及共聚物的表征

采用原位红外光谱技术对苯胺和环氧丙烷的电化学共聚机理进行了研究, 研究结果表明, 环氧丙烷能在苯胺及其低聚物阳离子自由基的催化作用下发生α位开环, 与苯胺发生电化学共聚, 生成了含有芳香-脂肪醚结构的共聚物. 采用显微红外成像技术研究苯胺和环氧丙烷共聚物在电极表面的生长特点发现, 该共聚物能在电极表面从中间向两侧有规律地生长.     

现场显微红外光谱电化学技术及超微铂盘电极的反射吸收光谱测定

本文阐述了一种新的光谱电化学技术－现场显微红外光谱电化学法的反射式方法的技术特点和优势，报告了一种适于水溶剂和非水溶剂的反射式现场显微红外光谱电化学池的设计，并首次在２５ｕｍ直径的超微铂盘工作电极上，对Ｆｅ（ＣＮ）＾４－６／ＦＥ（ＣＮ）＾３－６进行了现场显微红外光谱电化学的测量。     

红螺菌吸附重金属红外光谱及原子力成像比较研究

研究了红螺菌对Cu2 、Cr6 的吸附行为.结果表明,在pH 2.9,35℃微光厌氧条件下,菌体对40mg/L Cu2 、Cr6 最大吸附率分别为94%、83.2%.利用红外光谱、原子力成像等方法,对吸附Cu2 、Cr6 前后的红螺茵进行了研究.红外光谱表明,羟基峰位红移,吸附Cu2 后峰位移动为22cm-1,吸附Cr6 后移动28cm-1,其它峰没有漂移,并且峰形基本保持不变,说明吸附后菌体的主要成分及结构保持完整.原子力成像表明,吸附前胞外聚合物分散分布,吸附后胞外聚合物出现交联,形成一个新的二维网状结构,并且吸附Cu2 后的交联程度比吸附Cr6 高.     

同步辐射X射线成像技术在脑成像研究中的应用

脑疾病的诊疗、 探索高级脑功能机制和理解意识本源对脑科学研究具有重要意义. 成像技术在阐明脑科学神经系统结构和功能中发挥了重要作用. 迄今, 核磁共振成像、 光学成像和电子显微镜成像技术已为脑科学研究提供了强有力的手段, 取得了突出的进展. 同步辐射X射线显微成像技术具有高分辨率、 快成像速度和高穿透深度等优点, 是一类与已有技术互补的新型脑成像技术. 本文介绍了核磁共振波谱、 光学显微镜和电子显微镜等成像方法在脑成像领域中的应用, 重点阐述了同步辐射X射线成像的优势以及在脑结构成像和功能成像中的应用. 在此基础上, 展望了同步辐射X射线成像应用于脑科学研究的未来发展方向, 讨论了该技术在绘制人脑联接图谱中的优势及可行性.     

Application of FTIR imaging to detect dietary induced biochemical changes in brown and white adipocytes

Fourier Transform Infrared microspectroscopy Imaging (FTIR imaging) has powerful advantages when used as a complementary technique to histopathological investigations. The common histopathological investigations use a number of chemical fixatives and deparaffinizing agents that alter lipid profiles of biological tissues, particularly in lipid-rich adipose tissues. An infrared image is made of a multitude of pixels. For each pixel, identified by its (x,y) coordinates, corresponds an FTIR spectrum that reveals the chemical composition at this specific location. As a result, it allows biochemical analysis in selective locations within samples. Moreover, functional group distribution maps can be used as a staining free technique for spatial characterization of different biomolecules. Though FTIR imaging has been reported as a powerful approach to characterize adipose tissues, the biochemical heterogeneity within adipose tissues has not been acknowledged. This study shows relative changes in brown and white adipose tissues of mice due to consumption of high-fat diet. In particular, we report cryosectioning of adipose tissues, image acquisition, and different image analysis methods to evaluate dietary induced changes in lipids stored in brown and white adipocytes. Since biochemical changes in adipocytes constitute an important component in obesity investigations, this study shows the potential use of FTIR imaging to compare relative biochemical changes associated with dietary interventions.     

Visible Light‐Triggered Photoswitchable Diarylethene‐Based Iridium(III) Complexes for Imaging Living Cells

A novel diarylethene‐based iridium(III) complex was synthesized as a phosphorescence probe for monitoring living cells. The switchable phosphorescence complex in solution and within living cells was controlled by two distinguishable visible‐light irradiations, which suggests that this complex can be developed as a promising probe with weak photodamage for biological samples.     

Nondestructive Synchrotron Radiation X-Ray Fluorescence Imaging of Trace Elements on Methylmercury and Selenium Administered Guinea Pigs

Abstract

The dynamics of the brain distributions of Hg, Zn, Cu and Se in guinea pigs exposed to methylmercury and selenium were examined by X-ray fluorescence imaging utilizing synchrotron radiation.

Male Hartley guinea pigs were administered methyl mercury chloride and/or sodium selenite every day for ten days (s.c. 3mg as Hg/kg/day, mole ratio Hg:Se=1:1). Two dimensional distributions of Hg, Zn, Cu and Se in guinea pig brain were observed by nondestructive X-ray fluorescence imaging. Using the     

同步辐射在分子自组装研究中的应用

同步辐射是一种高亮度、高准直性、宽频谱的优质光源,其在物质原子或分子尺度的结构表征方面具有独特的优势。本文介绍了同步辐射在分子自组装研究中的一些应用,主要包括同步辐射X射线散射、时间分辨的小角X射线散射、时间分辨的X射线衍射、X射线精细结构谱,以及红外光谱,详细阐述了同步辐射X射线散射在层状结构、管状结构以及溶液中的组装体结构表征方面的应用。     

Analysis of Pathogenic Bacterial and Yeast Biofilms Using the Combination of Synchrotron ATR-FTIR Microspectroscopy and Chemometric Approaches

Biofilms are assemblages of microbial cells, extracellular polymeric substances (EPS), and other components extracted from the environment in which they develop. Within biofilms, the spatial distribution of these components can vary. Here we present a fundamental characterization study to show differences between biofilms formed by Gram-positive methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative Pseudomonas aeruginosa, and the yeast-type Candida albicans using synchrotron macro attenuated total reflectance-Fourier transform infrared (ATR-FTIR) microspectroscopy. We were able to characterise the pathogenic biofilms’ heterogeneous distribution, which is challenging to do using traditional techniques. Multivariate analyses revealed that the polysaccharides area (1200–950 cm⁻¹) accounted for the most significant variance between biofilm samples, and other spectral regions corresponding to amides, lipids, and polysaccharides all contributed to sample variation. In general, this study will advance our understanding of microbial biofilms and serve as a model for future research on how to use synchrotron source ATR-FTIR microspectroscopy to analyse their variations and spatial arrangements.     

Production of N3 upon Photolysis of Solid Nitrogen at 3 K with Synchrotron Radiation

The photodissociation of gaseous molecular nitrogen has been investigated intensively, but the corresponding knowledge in a solid phase is lacking. Irradiation of pure solid nitrogen at 3 K with vacuum‐ultraviolet light from a synchrotron produced infrared absorption lines of product l‐N₃ at 1657.8 and 1652.6 cm^?1. The threshold wavelength to generate l‐N₃ was determined to be (143.7±1.8) nm, corresponding to an energy of (8.63±0.11) eV. Quantum‐chemical calculations support the formation of l‐N₃ from the reaction N₂+N₂, possibly through an activated complex l‐N₄ upon photoexcitation with energy above 8.63 eV. The results provide a possible application to an understanding of the nitrogen cycle in astronomical environments.     

量子点-卟啉纳米复合体系在肿瘤细胞成像中的应用

本文合成了高荧光量子产率、单分散性好的水溶性CdTe量子点(quantum dots,QDs),并与α,β,γ,δ-四(1-甲基吡啶嗡-4-基)卟吩对甲苯磺酸盐(TMPyP)组装成QDs-TMPyP纳米复合物,研究了该复合物检测DNA的机理以及肿瘤细胞成像。结果显示,QDs-TMPyP纳米复合物通过光致电子转移机制检测DNA,当CdTe QDs和CdTe QDs-TMPyP浓度低于1.0μmol/L时,HeLa肿瘤细胞存活率达92%以上,表现出低的细胞毒性。0.2μmol/L CdTe QDs-TMPyP作用于肿瘤细胞时,细胞生长状态良好,对细胞内能谱分析发现细胞内含有Cd和Te原子。CdTe QDs-TMPyP复合物比CdTe QDs更易被HeLa细胞摄取,利用量子点荧光成功实现了细胞核内成像,为宫颈癌细胞药物输送和细胞成像的深入研究打下基础。     

Synchrotron Radiation for Structural Chemistry—Endohedral Natures of Metallofullerenes Found by Synchrotron Radiation Powder Method

The recent progress of the structural studies of endohedral metallofullerenes by the synchrotron radiation (SR) powder diffraction utilizing the maximum entropy method (MEM) is reviewed. Results of the endohedral metallofullerenes (Y@C₈₂, La@C₈₂, Sc@C₈₂, Sc₂@C₈₄, Sc₃@C₈₂, Sc₂@C₆₆, La₂@C₈₀ and Sc₂C₂@C₈₄) are given. The precise MEM charge densities of metallofullerenes presents the direct image of endohedral nature of metallofullerenes indicating the charge transfer from metal atoms to carbon cage, which governs the stability of the unique endohedral structures. The MEM/Rietveld method and SR powder method using imaging plate (IP), which are the crucial methods for data analysis and measurement in order to determine structure of fulleride, are also mentioned in some detail.     

Three‐Dimensional Mid‐Infrared Tomographic Imaging of Endogenous and Exogenous Molecules in a Single Intact Cell with Subcellular Resolution

Microscopy in the mid‐infrared spectral range provides detailed chemical information on a sample at moderate spatial resolution and is being used increasingly in the characterization of biological entities as challenging as single cells. However, a conventional cellular 2D imaging measurement is limited in its ability to associate specific compositional information to subcellular structures because of the interference from the complex topography of the sample. Herein we provide a method and protocols that overcome this challenge in which tilt‐series infrared tomography is used with a standard benchtop infrared microscope. This approach gives access to the quantitative 3D distribution of molecular components based on the intrinsic contrast provided by the sample. We demonstrate the method by quantifying the distribution of an exogenous metal carbonyl complex throughout the cell and by reporting changes in its coordination sphere in different locations in the cell.