Advanced Nanomaterials for Multimodal Molecular Imaging

The development of multimodal molecular imaging contrast agents based on versatile nanomaterials has recently attracted much attention in disease diagnosis and therapeutic delivery. Contrast agents made from nanoparticles and used for multimodal imaging in vivo provide a multidimensional pathophysiological overview of diseases. This review summarizes recently developed advanced nanomaterials for multimodal molecular imaging. We comprehensively discuss these nanoparticle contrast agents in terms of their targeting modalities, limitations in clinical translation and future directions.     

多种超分辨荧光成像技术比较和进展评述

所见即所得是生命科学研究的中心哲学,贯穿在不断认识单个分子、分子复合体、分子动态行为和整个分子网络的历程中.活的动态的分子才是有功能的,这决定了荧光显微成像在生命科学研究中成为不可替代的工具.但是当荧光成像聚焦到分子水平的时候,所见并不能给出想要得到的.这个障碍是由于受光学衍射极限的限制,荧光显微镜无法在衍射受限的空间...     

异核双金属探针在活细胞细胞核和线粒体中选择性定位DNA

用于实时成像活细胞DNA的细胞核探针是非常罕见的。通过Ru(N^N)₃、Ir(C^N)₂(N^N)、Re(CO)₃Cl(N^N)和Pt(C^N)(N^N)的结合,生成了4种异核双金属配合物：2种不同的功能金属位点被锚定在线性双齿螯和配体(N^N)-(N^N)的尾端,形成不对称哑铃状的双金属分子M₁-M₂,即Ru-Re、Ru-Pt、Ir-Re和Ir-Pt。Ru-Re和Ru-Pt的红色发射探针具有较大的斯托克斯位移、优异的核膜穿透能力、良好光稳定性的DNA结合能力。此外,Ru-Re和Ru-Pt探针的DNA成像可与专门用于活细胞细胞核DNA染色的Hoechst 33342商用染料相媲美,而Ir-Re和Ir-Pt探针直接靶向线粒体。不同探针的发光特性和选择性胞内定位高度依赖于在异核双金属配合物中的金属物种。     

Non-Destructive Detection of Moldy Walnuts Based on Hyperspectral Imaging Technology

Walnuts with their shells are a popular agricultural product in China. However, mildew from growth can sometimes be processed into foods. It is difficult to visually determine which walnuts have mildew without breaking the shells. A non-destructive method for detecting walnuts with mildew was studied by combining spectral data with image information. A total of 120 “Lüling” walnuts with shells were used for the mildew experiment. The characteristics of the spectral data from six surfaces of all samples were collected in the range of 370–1042 nm on days 0, 15, and 30. The spectrum was pretreated using SNV, and the feature bands were extracted using PCA and modeled using a support vector machine (SVM). The results show that the overall classification accuracy was 93%, with an of accuracy of 100% for INEN walnuts (normal internally and externally). The accuracy for IMEM walnuts (mildew internally and externally) reached 87.29%. There was an accuracy of 78.6% for IMEN walnuts (mildew internally and normal externally). The non-destructive detection of mildewed walnuts can be undertaken using hyperspectral imaging technology, which provides a new technique for exploring the mechanisms of walnuts with mildew.     

Functionalized Ultrasmall Iron Oxide Nanoparticles for T1-Weighted Magnetic Resonance Imaging of Tumor Hypoxia

Hypoxia is a common biological condition in many malignant solid tumors that plays an imperative role in regulating tumor growth and impacting the treatment’s therapeutic effect. Therefore, the hypoxia assessment is of great significance in predicting tumor development and evaluating its prognosis. Among the plenty of existing tumor diagnosis techniques, magnetic resonance imaging (MRI) offers certain distinctive features, such as being free of ionizing radiation and providing images with a high spatial resolution. In this study, we develop a fluorescent traceable and hypoxia-sensitive T₁-weighted MRI probe (Fe₃O₄-Met-Cy5.5) via conjugating notable hypoxia-sensitive metronidazole moiety and Cy5.5 dye with ultrasmall iron oxide (Fe₃O₄) nanoparticles. The results of in vitro and in vivo experiments show that Fe₃O₄-Met-Cy5.5 has excellent performance in relaxivity, biocompatibility, and hypoxia specificity. More importantly, the obvious signal enhancement in hypoxic areas indicates that the probe has great feasibility for sensing tumor hypoxia via T₁-weighted MRI. These promising results may unlock the potential of Fe₃O₄ nanoparticles as T₁-weighted contrast agents for the development of clinical hypoxia probes.     

Multimodal Imaging and Phototherapy of Cancer and Bacterial Infection by Graphene and Related Nanocomposites

The advancements in nanotechnology and nanomedicine are projected to solve many glitches in medicine, especially in the fields of cancer and infectious diseases, which are ranked in the top five most dangerous deadly diseases worldwide by the WHO. There is great concern to eradicate these problems with accurate diagnosis and therapies. Among many developed therapeutic models, near infra-red mediated phototherapy is a non-invasive technique used to invade many persistent tumors and bacterial infections with less inflammation compared with traditional therapeutic models such as radiation therapy, chemotherapy, and surgeries. Herein, we firstly summarize the up-to-date research on graphene phototheranostics for a better understanding of this field of research. We discuss the preparation and functionalization of graphene nanomaterials with various biocompatible components, such as metals, metal oxides, polymers, photosensitizers, and drugs, through covalent and noncovalent approaches. The multifunctional nanographene is used to diagnose the disease with confocal laser scanning microscopy, magnetic resonance imaging computed tomography, positron emission tomography, photoacoustic imaging, Raman, and ToF-SMIS to visualize inside the biological system for imaging-guided therapy are discussed. Further, treatment of disease by photothermal and photodynamic therapies against different cancers and bacterial infections are carefully conferred herein along with challenges and future perspectives.     

基于X光微点源的半影成像技术

基于X光微点源装置,从实验角度验证了半影成像的原理。利用针孔成像,直接测量了微点源源区图像;给出了半影孔成像、半影锥成像和环孔成像原理,以及在微点源的半影成像结果和维纳滤波重建结果。从实验结果可知：半影锥成像具有与半影孔成像相同的诊断能力,两种方法的重建图像尺寸与源尺寸一致;环孔成像的诊断能力更好,重建图像的尺寸和形状更接近源图像。     

太赫兹半导体器件与应用——纪念刘惠春教授

文章是以作者和刘惠春教授多年合作的研究工作为基础写成的,主要内容为太赫兹(THz)半导体器件及其通信和成像应用,以此深切缅怀刘惠春教授。近十年来,THz科学与技术已取得了长足进步,它在物理学、材料科学、生命科学、天文学、信息技术和国防安全等多个领域的应用也已初现端倪。在这些应用中,半导体THz器件的发展起着举足轻重的作用。文章着重介绍了作者近年来在半导体THz器件与应用方面的研究进展,主要内容包括基于负有效质量的电子学THz振荡器、飞秒激光泵浦半导体THz辐射源、基于量子阱子带间跃迁的THz量子级联激光器和THz量子阱探测器,以及基于这些器件的THz无线通信和成像应用研究。此外,文章还对未来THz技术的发展进行了简要的探讨。     

成像型速度干涉仪散斑成因的研究

在冲击波过程中,利用成像型速度干涉仪探测样品自由面的速度时,散斑的叠加使得干涉曲线被严重干扰,影响了速度信息的精密提取。在理论上从光路的角度分析了系统中可能造成散斑的两种因素：靶面粗糙度和多模光纤。在实验上设计了三种照明方式分别对这两种因素进行验证。离线实验的结果表明,多模光纤的引入对散斑的产生起了主要的作用,这对抑制乃至遏制散斑的产生具有很好的指导性意义。     

基于统计特性的激光雷达距离像噪声抑制算法

激光成像雷达在工作时会受到噪声干扰,因此需要滤除距离像中无法反映真实信息的异常点。根据激光成像雷达距离像噪声的分布,推导出距离像中非异常值的分布特性,并提出了一种距离像异常值的判定条件。将判定条件表示为小范围内抽样分布的函数,利用稳健统计中的中位值法可估算出判定条件的取值,从而可以移除异常点得到噪声抑制后的距离像。利用该算法分别对激光雷达距离像进行仿真和实际获得的激光雷达距离像进行处理并进行数学分析,并与中值滤波进行了比较,结果表明基于统计特性的噪声抑制算法同时具有很强的噪声抑制能力和保护目标细节信息能力,可以满足激光成像雷达距离像噪声抑制的要求。算法充分利用了激光成像雷达较高的测距精度,可以应对多种场景下的需求,具有很强的实用性。