基于咔唑的双光子荧光次氯酸根探针光学性质及响应机理

采用含时密度泛函理论与响应函数理论相结合的方法,研究了两种实验室新合成的水溶性双光子荧光次氯酸根（ClO^-）探针分子HCH和HCM的单光子吸收、双光子吸收和荧光发射性质。计算结果表明,HCH和HCM分子与ClO^-反应后,生成物的光吸收和光发射性质均发生明显变化,相应的吸收和发射峰位都发生了明显蓝移,荧光强度展现出明显的增强。另外,两探针分子都具有较大的双光子吸收截面,且与ClO^-反应后,生成物的双光子吸收截面值显著增加,因此两分子均可作为性能优良的双光子荧光探针分子。此外,通过分析HCH和HCM分子与ClO^-反应前后的Mulliken电荷布居情况,从理论上证实了该系列荧光探针分子的识别机理是C＝N异构化。     

(2-羧基苯氧基)苯-1,2-二羧酸构筑的镧系配合物对苯甲醛和阳离子的荧光传感

采用水热法合成了5个稀土配合物[Sm₂(bdbc)₂(phen)₄](1)和[Ln(bdbc)(phen)(H₂O)][Ln=Eu(2), Gd(3), Tb(4), Dy(5), bdbc=(2-羧基苯氧基)苯-1,2-二羧酸根, phen=1,10-邻菲啰啉]. 配合物1是双核分子, 通过氢键和C—H…π作用进一步构筑成一维超分子结构; 配合物2~5是同构的一维双螺旋结构, 通过氢键和C—H…π作用进一步构筑成三维超分子结构. 配合物1, 2, 4和5呈现了Sm³⁺, Eu³⁺, Tb³⁺和Dy³⁺离子的特征发射, 分别对应于Sm³⁺离子的⁴G_5/2→⁶H_J/2(J=5, 7, 9)、 Eu³⁺离子的⁵D₀→⁷F_J(J=1—4)、 Tb³⁺离子的⁵D₄→⁷F_J(J=6, 5, 4, 3)和Dy³⁺离子的⁴F_5/2→⁶H_J/2(J=15, 13)跃迁. 对配合物4的荧光性质进行了表征, 结果表明, 配合物4可用作荧光探针以检测阳离子和苯甲醛.     

基于矩阵分析的STR荧光解谱技术

用多种荧光标记物进行STR检测时,由于荧光光谱的谱带展宽特性,各个荧光光谱之间有重叠部分,如何实现将相互重叠的各个波长上的能量有效利用起来,对提高荧光利用效率至关重要。本文给出了一种基于矩阵分析的数据处理方法,该方法在进行荧光探测前首先要对荧光谱进行光谱校正,即要得到每种所用标记染料受激发射荧光的光谱分布,根据光谱分布建立染料组合荧光信号矩阵,然后对矩阵进行归一,利用归一后的矩阵对所探测的荧光谱进行解谱,从而得到所期望的荧光谱图。理论分析和实验结果表明,该方法可以有效的利用各个波长的荧光光谱能量,并实现对不同荧光重叠谱的有效光谱解谱。     

Fluorescence Spectroscopic Studies on Plasma-Chemically Modified Polymer Surfaces with Fluorophore-Labeled Functionalities

Molecular engineering of polymer surfaces that includes the attachment of functional molecules to existing or previously generated reactive chemical groups like e.g., − OH, − NH₂, or − CHO requires simple strategies and tools for the controlled generation of surface functionalities and their derivatization as well as for their identification and eventually quantification. Here, we systematically investigate the plasma-chemical surface modification of polypropylene films in combination with dansyl labeling chemistry and conventional, yet costly, XPS and highly sensitive fluorescence spectroscopy for the detection of surface groups. Based on these results, the potential of and requirements on the fluorometric characterization and quantification of surfaces functionalities are discussed.     

Recent developments in novel blue/green/red/NIR small fluorescent probes for in cellulo tracking of RNA/DNA G-quadruplexes

The detection and stabilization of G-quadruplexes (G4s) in living systems is of enormous applicability in the fields of chemical biology and therapeutic materials. Whereas DNA serves as a genetic material, RNA functions in the regulation and expression of genetic materials. Even there is various report on fluorescent probes invitro G4s recognitions, in this review we highlighted briefly, in-cellulo identification of G4s along with conventional methods principles. Although there are varieties of G4-forming sequences in the genome, targeting a specific type (topology) in living cells is highly challenging because of the high instability of G4s in cellular/subcellular systems. In contrast, several reports describe the in vitro identification of G4s, along with in-cell demonstrations, using efficient fluorescent probes, through either intrinsic or extrinsic approaches. In the intrinsic mode, the sensing results from the use of highly selective synthetic fluorescent oligonucleotides or proteins (a labeling approach). In the extrinsic mode, quencher-free small molecular probes are used to recognize specific G4s under physiological conditions. Because of their robustness, simplicity, and ease of handling, this review describes recent trends in the use of blue/green, green, red, and near-infrared (NIR) fluorescent probes for the recognition of G4s in live cells-and, particularly, those approaches employing quencher-free probes. Also highlighted are a few labeled probes, and their in cellulo localizations, which were accomplished upon the formation of non-canonical G4s under specified conditions and supplemented by exogenous G4-forming components, without harnessing cellular physiological conditions.     

豆奶粉提取碳点及含碳点荧光纳米纤维的制备

以豆奶粉为碳源, 以有机硅烷为钝化剂, 用水热合成法制备碳点, 采用静电纺丝技术, 以碳点与聚乙烯吡咯烷酮(PVP)共混溶液为纺丝液, 制备了含碳点的纳米纤维. 通过紫外吸收光谱、 荧光吸收光谱和荧光发射光谱表征了碳点性质. 结果显示, 所得碳点纳米纤维直径分布均匀, 形貌良好, 碳点分散溶液在340~540 nm的紫外光激发下发出强青绿色荧光, 荧光发射峰出现在550 nm处, 并且随着激发波长增加有微弱的红移.     

Synthesis and properties of novel extended BODIPYs with rigid skeletons

Novel extended BODIPYs fused with bicyclo rings were synthesized from bicyclopyrroles by combining Knoevenagel condensation, Suzuki coupling, and O-chelation. The absorption maxima of the BODIPYs ranged from the visible to near-infrared region and the compounds showed good solubility in organic solvents. The solubility of the bicycloBODIPY with 2-naphthyl groups at the α-position of the pyrrole units was particularly high. Heating converted distyrylBODIPY with bicyclo[2.2.2]octene to benzoBODIPY with absorption (748.5?nm) and fluorescence (775.0?nm) in the near-infrared region.     

Spectroscopic studies of a BINAM-based sensor: Highly selective fluorescent recognition of lysine in water solution through a nucleophilic substitution reaction

A BINAM-based compound (R)-1 is found to show significant fluorescence enhancement in the presence of Lys in aqueous solution (1%DMF). This probe achieves highly selective fluorescent recognition of Lys even in the presence of other natural amino acids. It can be used as a sensitive as well as selective fluorescent probe for Lys. The mechanism for the interaction of (R)-1 with Lys was studied by NMR and HRMS.     

A chloroacetate based ratiometric fluorescent probe for cysteine detection in biosystems

The specific detection of cysteine (Cys) over homocysteine (Hcy), glutathione (GSH) and other amino acids is of great significance for studying its biological functions as well as for the diagnosis of related diseases. Chloroacetyl group was often used as a reaction site for cysteine fluorescent probes for its sensitivity and selectivity. However, high background fluorescence and low stability are common problems encountered by such probes. Here, four chloroacetyl group based fluorescent probes (C1, C2, C3, and H4) was synthesized for a comparative study. We found that the inefficient quenching ability of chloroacetyl group turned into an advantage when connected with a ratiometric fluorophore. With the modification of chloroacetyl group, probe H4 displayed excellent ratiometric property and great selectivity for Cys, the stability was also improved. Additionally, the probe was successfully applied for quantitative detection of Cys in fetal bovine serum and real-time imaging in living HeLa cells with low toxicity.     

Poly(adenine) DNA-Templated Gold Nanocluster-Based Fluorescent Strategy for the Determination of Thiol-Containing Pharmaceuticals

The fluorescence intensity of poly(adenine) DNA-templated gold nanoclusters was shown to be significantly quenched by N-acetylcysteine through the formation of the Au-S metal-ligand bonds. On the basis of the fluorescence quenching phenomenon, a sensitive, turn-off, and label-free fluorescence method has been designed for the determination of thiol-containing pharmaceuticals using poly(adenine) DNA-templated gold nanoclusters as fluorescent probes. The assay exhibited sensitive determination of N-acetylcysteine with a linear dynamic range from 10?nM to 10?μM and a limit of detection of 3?nM. Furthermore, the proposed strategy was successfully applied for the determination of N-acetylcysteine levels in acetylcysteine granule samples. Thus, the method could provide a sensitive, simple, and rapid fluorescent sensing platform for the determination of thiol-containing pharmaceuticals.