一个基于NBD-NH2荧光团的增强型pH荧光探针及其细胞造影研究

本文以NBD-NH₂荧光团偶联N-(4-吡啶甲基)乙二胺质子受体构建了基于光致电子转移(PET)机制的pH探针NBD-Py。探针在pH 5.0~8.5范围内显示pH降低导致的荧光增强响应,pK_a为6.48。该响应不受胞内常见金属离子干扰且有良好的可逆性。研究表明质子受体中引入4-甲基吡啶修饰乙二胺是探针实现对弱酸/近中性pH响应的关键。HeLa细胞中的造影证实了探针的pH_i造影能力和溶酶体靶向性能,为溶酶体pH相关的生理过程研究提供了新的可靠手段。     

N-对甲苯磺酰-5-氨基间苯二甲酸构筑的一维配位聚合物的合成、晶体结构和荧光性质

采用普通溶液法和水热法分别合成了2个金属-有机配位聚合物：{[Cu（Ts-5-AIPA）（phen）（H₂O）]·H₂O}_n（1）和[Cd（Ts-5-AIPA）（phen）]_n（2）（Ts-5-AIPA=N-对甲苯磺酰-5-氨基间苯二甲酸根,phen=菲咯啉）,并用红外光谱、热重和X射线单晶衍射对配合物的结构进行了表征。结果表明：2个配合物均为单斜晶系,配合物1为P2₁/c空间群,配合物2为C2/c空间群;2个配合物均为一维链状结构,再通过氢键和π-π堆积作用形成三维超分子结构。另外,还研究了2个配位聚合物的荧光性质。     

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/Tris-HCl（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^-8mol·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。     

三聚氰酸钴配合物的合成、晶体结构及荧光性质

本文合成了一个新的配合物Co(H2CA)2(H2O)2(H3CA=三聚氰酸),并通过元素分析、红外、荧光和单晶X-Ray射线进行了表征。标题化合物属于三斜晶系,P1空间群,a=0.503 83(7)nm,b=0.699 82(10)nm,c=0.911 08(13)nm,α=90.107(2)°,β=98.032(2)°,γ=110.788(2)°,V=0.296 92(7)nm3,Z=1,R=0.038 2。在配合物中,Co(Ⅱ)离子与三聚氰酸配体上的N原子,配位水的O原子配位,形成规则的平面正方形配位构型。相邻的2个Co(Ⅱ)平面四边形单元通过配体三聚氰酸上的氢键形成三维网状结构。室温荧光光谱测定表明该化合物在420 nm处有强的荧光发射。     

Organic Fluorescent Molecule with High Solid State Lumines- cent Efficiency and Protonation Stimuli-response

A novel organic fluorophor with high solid state luminescent efficiency based on 1,4-bis（2,2-di（pyridin-2-yl）- vinyl）benzene （BDP2VB） was designed and synthesized. It emits faintly in solution, but becomes a strong emitter in the aggregate state, demonstrating its aggregation induced emission （AIE） property. According to the crystal struc- ture analysis, J-type aggregation was formed in the packing mode of the molecule, which was demonstrated to be beneficial to gain high fluorescent quantum efficiency in solid state. Additionally, the emission color of BDP2VB can change dramatically in solid state as well as in solution by the protonation stimuli.     

水相氟离子“turn-on”型荧光传感器

设计合成了香豆素衍生物7-(二叔丁基(对硝基苯醚)硅醚)-4-甲基-香豆素(DTBPC),研究了DTBPC在水中对氟离子的响应.在表面活性剂十六烷基溴化铵的存在下,氟离子断裂DTBPC分子中的Si—O键释放出香豆素阴离子,从而"turn-on"体系的荧光,响应时间为3min,检测限为60ppb,表明DTBPC可以在水相中高灵敏、快速、专一性地识别氟离子,有望应用于氟离子荧光传感器.     

NIR Mega‐Stokes Fluorophores for Bioorthogonal Labeling and Energy Transfer Systems–An Efficient Quencher for Daunomycin

A set of new azide‐ and alkyne‐bearing lepidinium‐based fluorophores were synthesized for bioorthogonal labeling schemes. These fluorescent dyes all show large Stokes‐shifts with emission maxima in the near‐infrared (NIR) region of the electromagnetic spectrum. The applicability of these dyes in the construction of energy‐transfer systems was tested using one of these new fluorescent tags and daunomycin (Dau), an anticancer drug with fluorescent features. These daunomycin conjugates are the very first examples of fluorescently modulated constructs of this anticancer agent. The dually labeled architectures proved that the applied fluorescent dye can be utilized as an efficient quencher for daunomycin. Enzymatic cleavage of a dually labeled enzyme substrate resulted in full recovery of the fluorescence of daunomycin. Such fluorescently modulated Dau conjugates can provide useful information for the mechanism of action of Dau‐regulated cell death processes.     

Multiplexed electrochemical immunoassay using streptavidin/nanogold/carbon nanohorn as a signal tag to induce silver deposition

An ultrasensitive multiplexed immunoassay method was developed by using streptavidin/nanogold/carbon nanohorn (SA/Au/CNH) as a novel signal tag to induce silver enhancement for signal amplification. The Au/CNH was prepared by in situ growth of nanogold on carboxylated CNH and functionalized with streptavidin. The SA/Au/CNH showed well dispersibility in physiological buffer and could sever as a common tracing tag to recognize biotinylated signal antibody. The immunosensor array was prepared on disposable screen-printed electrodes. Through sandwich-type immunoreaction and biotin-streptavidin affinity reaction, the SA/Au/CNH tag was captured on the immunoconjugates to induce silver deposition and amplify the electrochemical stripping signals. Using α-fetoprotein and carcinoembryonic antigen as model analytes, the proposed method showed wide linear ranges with the detection limits down to 0.024 pg mL⁻¹ and 0.032 pg mL⁻¹, respectively, and eliminated completely signal cross-talk between adjacent immunosensors. It provided a convenient, high-efficient and ultrasensitive electrochemical detection route for biological analytes, showing great potential in clinical application.     

Visual and fluorescent detection of acetamiprid based on the inner filter effect of gold nanoparticles on ratiometric fluorescence quantum dots

In this work, we develop a simple and rapid sensing method for the visual and fluorescent detection of acetamiprid (AC) based on the inner-filter effect (IFE) of gold nanoparticles (AuNPs) on ratiometric fluorescent quantum dots (RF-QDs). The RF-QDs based dual-emission nanosensor was fabricated by assembling green emissive QDs (QDs_539 nm, λ_em = 539 nm) on the surface of red emissive QDs (QDs_661 nm, λ_em = 661 nm)-doped silica microspheres. The photoluminescence (PL) intensity of RF-QDs could be quenched by AuNPs based on IFE. Acetamiprid can adsorb on the surface of AuNPs due to its cyano group that has good affinity with gold, which could induce the aggregation of AuNPs accompanying color change from red to blue. Thus, the IFE of AuNPs on RF-QDs was weakened and the PL intensity of RF-QDs was recovered accordingly. Under the optimized conditions, the PL intensity of the RF-QDs/AuNPs system was proportional to the concentration of AC in the range of 0.025–5.0 μg mL⁻¹, with a detection limit of 16.8 μg L⁻¹. The established method had been used for AC detection in environmental and agricultural samples with satisfactory results.     

Detection and quantification of plasma amyloid-β by selected reaction monitoring mass spectrometry

Amyloid-β (Aβ) in human plasma was detected and quantified by an antibody-free method, selected reaction monitoring mass spectrometry (SRM-MS) in the current study. Due to its low abundance, SRM-based quantification in 10 μL plasma was a challenge. Prior to SRM analysis, human plasma proteins as a whole were digested by trypsin and high pH reversed-phase liquid chromatography (RPLC) was used to fractionate the tryptic digests and to collect peptides, Aβ_1–5, Aβ_6–16, Aβ_17–28 and Aβ_29–40(42) of either Aβ_1–40 or Aβ_1–42. Among those peptides, Aβ_17–28 was selected as a surrogate to measure the total Aβ level. Human plasma samples obtained from triplicate sample preparations were analyzed, obtaining 4.20 ng mL⁻¹ with a CV of 25.3%. Triplicate measurements for each sample preparation showed CV of <5%. Limit of quantification was obtained as 132 pM, which corresponded to 570 pg mL⁻¹ of Aβ_1–40. Until now, most quantitative measurements of Aβ in plasma or cerebrospinal fluid have required antibody-based immunoassays. Since quantification of Aβ by immunoassays is highly dependent on the extent of epitope exposure due to aggregation or plasma protein binding, it is difficult to accurately measure the actual concentration of Aβ in plasma. Our diagnostic method based on SRM using a surrogate peptide of Aβ is promising in that actual amounts of total Aβ can be measured regardless of the conformational status of the biomarker.