High-Affinity Ratiometric Fluorescence Probe Based on 6-Amino-2,2′-Bipyridine Scaffold for Endogenous Zn2+ and Its Application to Living Cells

Zinc is an essential trace element involved in many biological activities; however, its functions are not fully understood. To elucidate the role of endogenous labile Zn²⁺, we developed a novel ratiometric fluorescence probe, 5-(4-methoxyphenyl)-4-(methylsulfanyl)-[2,2′-bipyridin]-6-amine (6 (rBpyZ)) based on the 6-amino-2,2′-bipyridine scaffold, which acts as both the chelating agent for Zn²⁺ and the fluorescent moiety. The methoxy group acted as an electron donor, enabling the intramolecular charge transfer state of 6 (rBpyZ), and a ratiometric fluorescence response consisting of a decrease at the emission wavelength of 438 nm and a corresponding increase at the emission wavelength of 465 nm was observed. The ratiometric probe 6 (rBpyZ) exhibited a nanomolar-level dissociation constant (K_d = 0.77 nM), a large Stokes shift (139 nm), and an excellent detection limit (0.10 nM) under physiological conditions. Moreover, fluorescence imaging using A549 human lung adenocarcinoma cells revealed that 6 (rBpyZ) had good cell membrane permeability and could clearly visualize endogenous labile Zn²⁺. These results suggest that the ratiometric fluorescence probe 6 (rBpyZ) has considerable potential as a valuable tool for understanding the role of Zn²⁺ in living systems.     

基于苯并吡喃腈-香豆素体系的近红外比率型荧光探针用于检测He La细胞中的过氧亚硝酸盐(英文)

过氧亚硝酸根(ONOO-)是生物体内的一种重要的活性氧,与人体内的各种生理活动息息相关.利用苯并吡喃腈-香豆素体系,合成了一种用于ONOO-检测的近红外比率型荧光探针(E)-7-(二乙胺基)-3-(2-(苯并吡喃腈)乙烯基)-香豆素(DCCM).该探针在ONOO-存在下表现出强烈的响应,颜色从紫色变为浅粉色,最大发射峰蓝移217nm,荧光颜色从淡紫色变为蓝色,能够直观地对溶液中的ONOO-进行监测. DCCM可以灵敏地检测ONOO^-,最低检测限为6.0×10^-7 mol·L^-1,该探针被成功用于HeLa细胞中的ONOO-成像检测.     

一种检测水合肼荧光探针的合成与应用

基于香豆素类染料,设计合成了一种具有较高选择性和灵敏度,可在生理条件(pH 7.4)下检测水合肼的荧光探针,同时利用核磁共振和高分辨质谱对探针的分子结构进行了表征。基于水合肼进攻探针分子结构中的4-丁酸酯,生成酚氧负离子,同时发生分子内环化反应后生成具有强烈荧光的亚胺香豆素,实现了探针分子对水合肼的检测。光谱学研究表明,当向探针溶液加入水合肼(0~100μmol/L)后,探针溶液在绿色光谱区域(502 nm)呈现一个显著的荧光增强响应(增强至55倍)。并且,探针可以检测相对较低浓度的水合肼,检出限为1.7×10~(-7)mol/L。此外,相对于其他阴离子和亲核试剂,探针对水合肼的识别显示出较高的选择性和灵敏度。探针成功实现了细胞内水合肼的荧光成像,证明其在细胞成像中具有潜在的应用能力。     

罗丹明6G衍生物基偏酸性“关开型”pH荧光探针

以罗丹明6G和水合肼为原料,先制备罗丹明6G酰肼,接着在乙醇中滴加少量冰醋酸做催化剂后与2,5-二甲氧基苯甲醛反应,合成了一种新型的pH荧光分子探针(RGSBD),进行了结构表征及荧光性能研究。结果表明,原本在氢离子浓度较低,即体系pH较高时(pH≥4.0),探针RGSBD内酰胺螺环闭环导致不显示荧光并且无色,然而在氢离子浓度较大即体系pH较低时(pH<4.0)时,其内酰胺螺环闭环产生了明显的颜色变化,发出强烈的荧光。pH 1.9时,探针的荧光强度达到最大,最大荧光峰发生显著的红移。进一步研究表明,探针RGSBD的荧光峰强度差值与pH在1.9~3.2范围内呈良好的线性关系,探针RGSBD识别H^+的选择性高,稳定性与可逆性强,可发展用作生物体内pH荧光传感材料。     

Quest for novel fluorogenic xanthene dyes: Synthesis,spectral properties and stability of 3-imino-3H-xanthen-6-amine (pyronin) and its silicon analog

To expand the range of primary aniline fluorophores available and suitable for the design of fluorogenic protease probes, the synthesis of 3-imino-3H-xanthen-6-amine (known as pyronin) and its silicon analog (Si-pyronin) was explored and presented here. A comprehensive photophysical study of these two fluorescent anilines, confirms the effectiveness of the heteroatom-substitution approach (O?→?SiMe₂) to yield dramatic red-shifts in absorption and fluorescence maxima of the xanthene scaffold (+85?nm). However, it also revealed its adverse effect on the hydrolytic stability of the Si-pyronin, especially at physiological pH. The pro-fluorescent character and utility of these two fluorogenic (hetero)xanthene dyes are also proved by the preparation and in vitro validation of activatable fluorescence “turn-on” probes for penicillin G acylase (PGA).     

Preparation of cinnoline-3, 4-dicarbonitrile and -dicarboxylic acid

Attempts to prepare cinnoline-3,4-dicarboxylic acid from 3,4-dimethylcinnoline failed owing to the unreactivity of the 3-me group. Successive treatment of 3-bromo-4-chlorocinnolin with sodium toluene-p-sulphinate and potassium cyanide in dimethylformamide (DMF) gave 4-toluene-p-sulphonylcinnoline-3-carbonitrile and then cinnoline-3,4-dicarbonitrile (82%). Hydrolysis yielded cinnoline-3,4-dicarboxylic acid (53%). Cinnoline-3, 4-dicarbonitrile undergoes nucleophilic displacement of either the 4- or the 3-cyano group by ammonia or amine to give 4-amino- and 4-benzylaminocinnoline-3-carbonitrile but 3-dimethylamino-cinnoline-4-carbonitrile.     

A proximity-induced covalent fluorescent probe for selective detection of bromodomain 4

Through proximity-induced conjugation reaction, a peptide-based fluorescent probe was designed and synthesized for selective detection of bromodomain 4.     

氨基苯基类中氮茚化合物的合成及作为质子探针的研究

设计合成了3个氨基苯基类中氮茚化合物, 研究了其在不同pH值的缓冲溶液中的荧光强度变化. 结果表明, 在pH=2.1～4.2之间, 该类化合物具有荧光敏感性. 化合物3a和3b可以作为良好的质子控制的荧光开关器件信号分子.     

芳基吡啶类Fe3+荧光探针的合成与分析应用

设计合成了两种新型的以2-苯基苯并噻唑为荧光团、N-(2-吡啶甲基)胺为识别基团的铁离子荧光分子探针2-(4-N-2-吡啶甲胺基)苯基-1,3-苯并噻唑(A1)和2-(4-N,N双2-吡啶甲胺基)苯基-1,3-苯并噻唑(A2),化合物结构用UV,IR,1HNMR和13CNMR进行了表征,并考察了探针的荧光特性.结果表明荧光分子探针A2在CH3 CH2OH/H-12O(1∶1,V/V)溶液中,能从常见的金属离子中以95％的荧光淬灭率选择性地识别铁离子,对Fe3+线性响应范围在0.15～1.3 μ mol/L之间,且检出限达10 nmol/L.     

用于检测细胞内谷胱甘肽的比率型荧光探针

设计合成了1种用于检测生物巯基的比率型荧光探针(4),并考察了其对谷胱甘肽的识别作用.在4-羟乙基哌嗪乙磺酸(HEPES)缓冲液中,探针4可与谷胱甘肽快速反应,溶液颜色由淡黄色变为粉红色,从而实现"裸眼"检测,且在608 nm处的荧光信号增强.在1.6×10-5~2×10-4mol/L范围内,探针4能够定量检测谷胱甘肽,检出限为8.9×10-7mol/L.此外,探针4还可用于MCF-7细胞中谷胱甘肽的成像.     

A 4-Methylumbelliferone-based Fluorescent Probe for Sodium New Houttuyfonate

A new fluorogenic probe for sodium new houttuyfonate (SNH) was proposed. 4‐Methylumbelliferyl‐2,4‐dinitrobenzenesulfonate (4‐MUDNBS) was a nonfluorescent compound and was synthesized via the one‐step reaction of 4‐methylumbelliferone (4‐MU) with 2,4‐dinitrobenzenesulfonyl chloride. In basic media, SNH was decomposed to produce sodium sulfite, which then reacted with 4‐MUDNBS to yield highly fluorescent 4‐MU, hence leading to the fluorescence increase of the reaction solution. A linear correlation existed between the emission intensity and the concentration of SNH within the range from 0.5 to 15 μg·mL⁻¹ with a detection limit of 0.15 μg· mL⁻¹ (3δ). The effect of substituents on the benzenesulfonyl moiety of the probe is discussed, and the presence of electronegative groups is favorable for the proposed cleavage reaction.     

Parametric signal fitting by gaussian peak adjustment: a new multivariate curve resolution method for non-bilinear voltammetric measurements

A novel two-photon fluorescence probe for Pb²⁺ derived from 4-methyl-2,5-dicyano-4′-amino stilbene as a two-photon fluorophore and bis[2-(2-aminophenylsulfanyls)ethyl]amine as a novel Pb²⁺ ligand was developed. The probe possesses small molecule size, large two-photon absorption cross-section (1020 GM), noncytotoxic effect, long-wavelength emission at 609 nm, large Stokes shift (209 nm), excellent photostability, moderate water-solubility, good cell-permeability, and pH-insensitivity in the biologically relevant pH range. The probe can selectively detect Pb²⁺ ions in live cells and living tissues without interference from other metal ions and the membrane-bound probes, and its quenching constant () is 7.58 × 10⁵ M⁻¹.     

双氰基二苯代乙烯型双光子荧光汞离子探针

分别以双氰基二苯代乙烯(DCS)和双[2-(2-羟乙基硫基)乙基]氨(HSA)为双光子荧光团和汞离子受体,合成了双光子荧光汞离子探针(DHg),并对其结构进行了分析.实验结果表明,DHg在甲苯、乙腈和水中的荧光量子产率(Φ)分别为0.78,0.42和0.20,对汞离子的络合常数通过单、双光子荧光滴定分别拟合为lg K=5.47±0.02和lg K=5.34±0.02.DHg在水溶液中对汞离子具有优良的选择性和高的灵敏性,可用于中性环境中汞离子的检测.DHg的双光子吸收截面(δTPA)在水溶液中高达840 GM,可用于细胞中汞离子的检测与成像.     

一种新型快速检测半胱氨酸的荧光探针EI北大核心CSCD

基于三苯胺母体的强供电子能力,设计合成了一种共轭性良好的新型半胱氨酸(Cys)荧光探针。采用荧光光谱法和紫外-可见光谱法研究了目标探针T-Probe对半胱氨酸(Cys)的光谱响应。结果表明:目标探针分子与Cys作用后,荧光发射波长有约20 nm红移,荧光强度发生明显的增强,在365 nm紫外灯下,溶液由青色变为蓝色;探针分子选择性识别Cys的检测限为98.4 nmol/L,且灵敏度较高。     

谷胱甘肽和凋亡酶-3响应的环肽分子荧光探针

设计、合成了一类新型谷胱甘肽(glutathione,GSH)和凋亡酶-3(Caspase-3)响应的环肽分子荧光探针.该类探针主要由能量共振转移(FRET)分子荧光对、Caspase-3特异性识别多肽序列和GSH响应双硫键组成,分为不含穿膜肽序列(CP)和包含穿膜肽序列(cp CP)的两种不同环肽分子荧光探针.2种环肽分子荧光探针均能实现在GSH和Caspase-3同时存在情况下的精确成像,同时具有良好的响应性、特异性和高信噪比.该类环肽分子荧光探针在细胞培养环境中具有良好的稳定性和生物相容性.利用该探针,可以实现对星形孢菌素(STS)诱发的细胞凋亡进行实时、原位的成像监测,并对抗肿瘤药物阿霉素(DOX)和顺铂(cisplatin)诱导的细胞凋亡进行成像.这种具有多重响应并能用于精确成像的分子荧光探针将极大地促进疾病的精确诊断.     

一种用于细胞核成像的新型双光子荧光探针

本文报道了具有大双光子活性吸收截面的DNA探针BMVEC, 同时首次利用双光子显微镜完成了与DAPI的复染实验, 实验结果证实了BMVEC对细胞核的选择性标记能力.     

一种增强型荧光探针检测CN-及在细胞中的应用

以甲醇为溶剂,2-羟基-1-萘甲醛和2-氨甲基吡啶1∶1结合生成了一种简单的希夫碱增强型荧光探针(L)。该探针在DMSO∶H₂O(3∶2,V/V)的水溶液中加入CN^-后,荧光可增强8倍,线性范围为0~120×10^-5M,通过核磁滴定证明此作用机理为CN^-的去质子化作用。此外,通过荧光共聚焦成像,化合物L可高效选择性地检测人体SiHa癌细胞中的CN^-。     

一种基于联萘衍生物荧光探针的合成及其对精氨酸的识别

构建了一种基于(R)-2,2'-二羟基-[1,1'-联萘]-3-醛的荧光探针。 通过核磁共振波谱仪(NMR)以及质谱(MS)等技术手段对其结构进行了表征。 结果表明,该荧光探针能够灵敏、高选择性地检测精氨酸,并显示出颜色和强烈的荧光变化双重响应。 相应的荧光增强比值与精氨酸的浓度(0~30 μmol/L)呈现良好的线性关系,相关系数R²为0.9914,检测限低至1.3 μmol/L。 此外,精氨酸的加入还促使该探针结构中的联萘酚手性结构发生偏转。     

Facile synthesis of an optical sensor for CO32− and HCO3− detection

A novel fluorogenic signalling probe (E)-3-(4-methoxyphenyl)-4-[(4-nitrobenzylidene)amino]-1H-1,2,4-triazole-5(4H)-thione (6) for the carbonate and bicarbonate ions has been developed through microwave assisted Schiff base formation reaction. The anion recognition occurs through hydrogen bonding assessed by ¹H NMR titration experiments. The photophysical results of probe 6 corroborates its applicability as an optical sensing platform for carbonate as well as bicarbonate ions in mixed aqueous organic media depending on pH of reaction solution. The fluorescence emission signal enhancement at 424 nm and considerable shift in the signal position as well as molar absorptivity to the probe absorption bands upon CO₃^2? and HCO₃^? addition suggest the affinity of probe 6 towards these ions in comparison to a variety of competitive ions in aqueous/ethanol (7:3, v/v) at neutral pH and ambient temperature. From the fluorescence titration experiment, the limit of detection was calculated to be 1.91 μM.     

A self-assembly/disassembly two-photo ratiometric fluorogenic probe for bacteria imaging

A fluorogenic probe for bacteria imaging was reported. The binding with anionic bacterial surfaces disassembled the self-assembly probe to turn-on the fluorescence and shift pyrene monomer/excimer ratiometric signals.