Nanoscale MnII‐Coordination Polymers for Cell Imaging and Heterogeneous Catalysis

A mixed ligand approach was exploited to synthesize a new series of Mn^II‐based coordination polymers (CPs), namely, CP1 {[Mn(μ‐dpa)(μ‐4,4′‐bp)]?MeOH}_∞, CP2 {[Mn₃(μ‐dpa)₃(2,2′‐bp)₂]}_∞, CP3 {[Mn₃(μ‐dpa)₃(1,10‐phen)₂]?2 H₂O}_∞, CP4 {[Mn(μ‐dpa)(μ‐4,4′‐bpe)_1.5]?H₂O}_∞, CP5 {[Mn₂(μ‐dpa)₂(μ‐4,4′‐bpe)₂]? DEF}_∞, and CP6 {[Mn(μ‐dpa)(μ‐4,4′‐bpe)_1.5]? DMA}_∞ (dpa=3,5‐dicarboxyphenyl azide, 2,2′‐bp=2,2′‐bipyridine, 1,10‐phen=1,10‐phenanthroline, 4,4′‐bpe=1,2‐bis(4‐pyridyl)ethylene, 4,4′‐bp=4,4′‐bipyridine, DEF=N,N‐diethylformamide, DMA=N,N‐dimethylacetamide), to develop multifunctional CPs. Various techniques, such as single‐crystal X‐ray diffraction (SXRD), FTIR spectroscopy, elemental analysis, and thermogravimetric analysis, were employed to fully characterize these CPs. The majority of the CPs displayed a four‐connected sql topology, whereas CP4 and CP6 exhibited a two‐dimensional SnS network architecture, which was further entangled in a polycatenation mode. Compound CP1 displayed an open framework structure. The CPs were scaled down to the nanoregime in a ball mill for cell imaging studies. Whereas CP2 and CP4 were employed for cell imaging with RAW264.7 cells, CP1 was exploited for both cell imaging and heterogeneous catalysis in a cyanosilylation reaction.     

Quantitative,In Situ Visualization of Metal‐Ion Dissolution and Transport Using 1H Magnetic Resonance Imaging

Quantitative mapping of metal ions freely diffusing in solution is important across a diverse range of disciplines and is particularly significant for dissolution processes in batteries, metal corrosion, and electroplating/polishing of manufactured components. However, most current techniques are invasive, requiring sample extraction, insertion of an electrode, application of an electric potential or the inclusion of a molecular sensor. Thus, there is a need for techniques to visualize the distribution of metal ions non‐invasively, in situ, quantitatively, in three dimensions (3D) and in real time. Here we have used ¹H magnetic resonance imaging (MRI) to make quantitative 3D maps showing evolution of the distribution of Cu²⁺ ions, not directly visible by MRI, during the electrodissolution of copper, with high sensitivity and spatial resolution. The images are sensitive to the speciation of copper, the depletion of dissolved O₂ in the electrolyte and show the dissolution of Cu²⁺ ions is not uniform across the anode.     

Cross‐Platform DNA Encoding for Single‐Cell Imaging of Gene Expression

Integration of imaging data across different molecular target types can provide in‐depth insight into cell physiology and pathology, but remains challenging owing to poor compatibility between target‐type‐specific labeling methods. We show that cross‐platform imaging analysis can be readily achieved through DNA encoding of molecular targets, which translates the molecular identity of various target types into a uniform in situ array of ssDNA tags for subsequent labeling with complementary imaging probes. The concept was demonstrated through multiplexed imaging of mRNAs and their corresponding proteins with multicolor quantum dots. The results reveal heterogeneity of cell transfection with siRNA and outline disparity in RNA interference (RNAi) kinetics at the level of both the mRNA and the encoded protein.     

Spatially Heterogeneous Nature of Self‐Catalytic Reaction in Hetero‐Double Helix Formation of Helicene Oligomers

A 1:1 mixture of pseudoenantiomeric aminomethylenehelicene oligomers, (P)‐tetramer and (M)‐pentamer, in fluorobenzene show a self‐catalytic phenomenon in the formation of hetero‐double helices from random coils. This study visualizes the spatially heterogeneous nature of the self‐catalytic reaction in dilute solution. UV/Vis imaging analysis of the mixture at 70 °C, containing random coils, exhibits a homogeneous bright area. When the solution is cooled from 70 to 30 °C and held at that temperature, dark domains of approximately 1 mm in size appear, which move approximately at a rate of 1 mm min^?1. The dark domains indicate that weaker UV/Vis absorption results from the formation of hetero‐double helices, which is supported by circular dichroism (CD) imaging experiments. Then a homogeneous mixture is regenerated upon heating to 55 °C, as shown by CD imaging. Under self‐catalytic conditions, a homogeneous solution spontaneously changed to a heterogeneous solution in the process of hetero‐double‐helix formation.     

Bio‐/Chemosensors and Imaging with Aggregation‐Induced Emission Luminogens

Aggregation‐induced emission (AIE) luminogens show abnormal fluorescent behavior; they are non‐emissive in solution, but they become strongly emissive after aggregation. Sensing and imaging are the major applications of AIE luminogens. By properly manipulating the aggregation and deaggregation of AIE molecules, various bio‐/chemosensors have been developed. Moreover, AIE molecules with targeting groups have been devised for imaging of organelles and cancer cells. In this account, we report our recent work on the application of AIE luminogens for the construction of bio‐/chemosensors and imaging.

     

Functionalized Conjugated Polyelectrolytes for Biological Sensing and Imaging

Conjugated polyelectrolytes (CPEs) are macromolecules with highly delocalized π‐conjugated backbones and charged side chains, which are unique types of active materials, with wide applications in optoelectronics, sensing, imaging, and therapy. By attaching specific groups (e.g., recognition elements, magnetic resonance (MR) contrast agents, gene carriers, and drugs) to the side chain or backbone of CPEs, functionalized CPEs have been developed and used for specific biological applications. In this account, we summarize the recent progress of functionalized CPEs with respect to their synthesis and biomedical applications. Future perspectives are also discussed at the end.     

二阶关联成像系统宽光谱吸收膜研制

为满足关联成像系统抑制背景的需求,选用Al、Cr和SiO_2作为镀膜材料,依据薄膜吸收理论,结合膜系设计软件设计了宽光谱吸收膜,并采用真空沉积技术获得了该薄膜样品.通过真空阶梯式退火,减小了膜层内应力,解决了薄膜牢固度问题;采用交互式分析对测试结果逆向反演,通过优化工艺参量,使膜系中敏感薄层厚度得以精准控制,并减小了膜厚控制误差.制备的吸收膜在400~1 100nm波段平均吸收率达到99.1%,满足系统使用要求.     

单臂压缩感知鬼成像的光强扩散函数分析法

为了提高单臂压缩感知鬼成像的成像质量,减少成像系统本身和外部环境的干扰,提出了一种光强扩散函数分析方法.在单臂压缩感知鬼成像原理的基础上分析了成像过程,指出降低成像质量的主要因素是菲涅尔衍射和大气湍流.针对这两个因素,推导并分析了光强度扩散函数的公式,研究透镜的焦距与口径之比和照明光源的波长对鬼成像的影响.仿真结果表明:在单臂压缩感知鬼成像中,使用焦距与尺寸半径之比在2~5范围内的成像投影透镜可以消除衍射效应的影响;短波长光源适用于大气湍流较弱时的成像,长波长光源在大气湍流较强时对干扰有更好的耐受能力.该方法可以有效地提高成像质量并优化成像系统.