Protease Probes that Enable Excimer Signaling upon Scission

Peptide‐based probes that fluoresce upon proteolytic cleavage are invaluable tools for monitoring protease activity. The read‐out of protease activity through pyrene excimer signaling would be a valuable asset because the large Stokes shift and the long lifetime of the excimer emission facilitate measurements in autofluorescent media such as blood serum. However, proteolytic cleavage abolishes rather than installs the proximity relationships required for excimer signaling. Herein, we introduce a new probe architecture to enable the switching on of pyrene excimer emission upon proteolytic scission. The method relies on hairpin‐structured peptide nucleic acid (PNA)/peptide hybrids with pyrene units and anthraquinone‐based quencher residues positioned in a zipper‐like arrangement within the PNA stem. The excimer hairpin peptide beacons afforded up to a 50‐fold enhancement of the pyrene excimer emission. Time‐resolved measurements allowed the detection of matrix metalloprotease 7 in human blood serum.     

High‐Throughput Development of a Hybrid‐Type Fluorescent Glutamate Sensor for Analysis of Synaptic Transmission

Fluorescent sensors are powerful tools for visualizing cellular molecular dynamics. We present a high‐throughput screening system, designated hybrid‐type fluorescence indicator development (HyFInD), to identify optimal position‐specific fluorophore labeling in hybrid‐type sensors consisting of combinations of ligand‐binding protein mutants with small molecular fluorophores. We screened sensors for glutamate among hybrid molecules obtained by the reaction of four cysteine‐reactive fluorescence probes with a set of cysteine‐scanning mutants of the 274 amino acid S1S2 domain of AMPA‐type glutamate receptor GluA2 subunit. HyFInD identified a glutamate‐responsive probe (enhanced glutamate optical sensor: eEOS) with a dynamic range >2400 %, good photostability, and high selectivity. When eEOS was specifically tethered to neuronal surfaces, it reliably visualized the spatiotemporal dynamics of glutamate release at single synapses, revealing synapse‐to‐synapse heterogeneity of short‐term plasticity.     

Supramolecular Interactions of Nonsteroidal Anti‐inflammatory Drug in Nanochannels of Molecular Containers: A Spectroscopic,Thermogravimetric and Microscopic Investigation

Supramolecular host–guest complexation between the nonsteroidal anti‐inflammatory drug indomethacin (IMC) and molecular containers were investigated. The weakly fluorescent drug molecule becomes highly fluorescent on complexation with different molecular containers, and time‐resolved fluorescence emission spectroscopy reveals that the lifetime components of IMC significantly increase in the presence of molecular containers, compared with the lifetimes in neat water. The respective solid host–guest complexes were synthesised and characterised by Fourier transform infrared and ¹H nuclear magnetic resonance spectroscopic analysis. Microscopy techniques were used to analyse modifications of the surface morphology, owing to the formation of supramolecular complexes. The effect of the molecular container on the optical properties of IMC has also been investigated to determine the effect of nanochannels of different size and structure.     

Highly Sensitive and Selective Fluorometric/Electrochemical Dual‐Channel Sensors for TNT and DNT Explosives

A novel electro‐active compound, TCAC , is synthesized and its electrochemical polymerized film is used to detect 2,4,6‐trinitrotoluene (TNT) and 2,4‐dinitrotoluene (DNT) explosives through a fluorometric/electrochemical dual‐channel sensor with high sensitivity and selectivity. In particular, the electrochemical sensor for the analysis of TNT had an enhanced sensitivity of 0.5 μM . The detection limit of the sensor was calculated to be 15 nM .     

Straightforward Access to Water‐Soluble Unsymmetrical Sulfoxanthene Dyes: Application to the Preparation of Far‐Red Fluorescent Dyes with Large Stokes’ Shifts

An efficient synthesis of water‐soluble unsymmetrical sulforhodamine/sulforhodol fluorophores containing a single julolidine fragment is presented. Owing to their valuable spectral properties in aqueous buffers, these dyes, especially those bearing a free aniline or phenol moiety, are valuable components of fluorogenic probes for a variety of biosensing applications. A further extension of this synthetic methodology to unusual phenols, namely 7‐N,N‐dialkylamino‐4‐hydroxy coumarins has enabled us to provide a new family water‐soluble dyes of large Stokes’ shift with far‐red spectral features.     

N‐Heterocyclic Carbene Formation Induced Fluorescent and Colorimetric Sensing of Fluoride Using Perimidinium Derivatives

In this study, two perimidinium derivatives ( 1 and 2 ) were designed, synthesized, and developed as efficient fluorescent and colorimetric chemodosisensors for F^? in DMSO or more competitive media (DMSO containing 10 % water). In the presence of F^?, the yellow and non‐fluorescent solution of 1/2 became colourless and exhibited strong blue fluorescence. This unique spectroscopic behaviour of 1/2 towards F^? was attributed to the formation of N‐heterocyclic carbene deprotonated by F^?, which immediately reacted with water to give a colourless and fluorescent carbinol. Interestingly, it was found that this carbinol intermediate was unstable and further underwent a redox disproportionation to generate two other optically changed compounds. All the proposed mechanisms for the sensing process have been carefully confirmed by experiments.     

Highly Selective Detection of Nerve‐Agent Simulants with BODIPY Dyes

Two chromo‐fluorogenic probes, each based on the boron dipyrromethene core, have been developed for the detection of nerve‐agent mimics. These chemosensors display both a color change and a significant enhancement of fluorescence in the presence of diethylcyanophosphonate (DCNP) and diisopropylfluorophosphate (DFP). No interference from other organophosphorus compounds or acids has been observed. Two portable chemosensor kits have been developed and tested to demonstrate its practical application in real‐time monitoring.     

金属离子导向自组装的磺酰化对氨基苯甲酸配合物的合成与表征

用普通溶液法合成了4个配合物:[Cu(Ts-p-aba)2(phen)(H2O)]n(1)、[Zn(Ts-p-aba)2(phen)(H2O)]·H2O(2)、[Pb(Ts-p-aba)2(phen)]2(3)和{[Pb(Ts-p-aba)(phen)(NO3)](DMF)}n(4)(Ts-p-aba=N-对甲苯磺酰对氨基苯甲酸,phen=菲咯啉,DMF=N,N-二甲基甲酰胺)。X-射线单晶衍射结果表明:配合物1和2均为三斜晶系,P1空间群。配合物1的中心铜离子处于变形的八面体配位环境,并通过配体N-对甲苯磺酰对氨基苯甲酸扩展为一维直线链结构;配合物2是个单核分子,锌离子的配位多面体为四角锥体。配合物3和4均为单斜晶系,P21/c空间群。配合物3由配体N-对甲苯磺酰对氨基苯甲酸桥联成二聚体,铅离子处于变形的八面体配位环境;配合物4是具有一维链状结构的配位聚合物,铅离子处于变形的一面心八面体配位环境。另外,对4个配合物的热稳定性、电化学性能和荧光性质也进行了研究。     

一种基于DPA识别基团的可视化检测锌离子的荧光增强型探针

以N,N-二(2-吡啶甲基)胺(DPA)为识别基团,设计合成了一种用于检测Zn2+的荧光增强型探针WN,在CH3CH2OH/TrisHCl(1∶9,V/V,pH=7.4)缓冲溶液中研究了它对Zn2+的识别特性。实验结果表明,WN对Zn2+有较高的选择性和灵敏度,它们之间的结合比为1∶1,对Zn2+的检出限为1.14×10-8 mol·L-1。WN能够快速地可视化检测Zn2+,在HeLa活细胞中对Zn2+的荧光显微成像表明WN可应用于生物体的检测。     

基于柔性双吡啶双酰胺和两种不同多羧酸配体的三个Cu(Ⅱ)/Co(Ⅱ)配位聚合物:组装、结构和性质(英文)

通过水热合成得到3个有机金属配位聚合物,即[Cu(1,2-BDC)(L)](1),[Cu(HBTC)(L)]·2H2O(2),[Co(HBTC)(L)]·H2O(3),(L=N,N-双(3-氨基吡啶)乙二酰胺,1,2-H2BDC=1,2-邻苯二甲酸和H3BTC=1,3,5-均苯三甲酸)。配合物1是基于1D[Cu-1,2-BDC]n和[CuL]n链形成的一个3DCdSO4-型拓扑结构。配合物2~3是同构的,均显示出2D双层(3,5)-连接的{42·67·8}{42·6}拓扑结构。相邻的2D双层网络通过分子间的氢键(配合物2)和π-π堆积(配合物3)作用进一步拓展成3D超分子框架。我们对芳香羧酸和中心金属离子对配合物结构的影响进行了详细的讨论。此外,还研究了配合物1~3的电化学性质和固态荧光性质。