Hydroxylated graphene quantum dots as fluorescent probes for sensitive detection of metal ions

Highly sensitive methods are important for monitoring the concentration of metal ions in industrial wastewater.Here,we developed a new probe for the determination of metal ions by fluorescence quenching.The probe consists of hydroxylated graphene quantum dots(H-GQDs),prepared from GQDs by electrochemical method followed by surface hydroxylation.It is a non-reactive indicator with high sensitivity and detection limits of 0.01μM for Cu2+,0.005μM for Al3+,0.04μM for Fe3+,and 0.02μM for Cr3+.In addition,the low biotoxicity and excellent solubility of H-GQDs make them promising for application in wastewater metal ion detection.

A compact fluorescence/circular dichroism dual-modality probe for detection, differentiation, and detoxification of multiple heavy metal ions via bond-cleavage cascade reactions

Selective detection of multiple analytes in a compact design with dual-modality and theranostic features presents great challenges. Herein, we wish to report a coumarin-thiazolidine masked D-penicillamine based dual-modality fluorescent probe COU-DPA-1 for selective detection, differentiation, and detoxification of multiple heavy metal ions(Ag^(+), Hg^(2+), Cu^(2+)). The probe shows divergent fluorescence(FL)/circular dichroism(CD) responses via divergent bond-cleavage cascade reactions(metal ion promoted C-S cleavage and hydrolysis at two distinctive cleavage sites): FL “turn-off” and CD “turn-on” for Ag+(no hydrolysis), FL “turn-on” and CD “turn-off” for Hg^(+)(imine hydrolysis), and FL “self-threshold ratiometric” and CD “turn-off” for excess Cu^(2+)(lactone and imine hydrolysis), providing the first example of a fluorescence/CD dual-modality probe for multiple species with complimentary responses. Moreover, the bond-cleavage cascade reactions also lead to the formation of D-penicillamine heavy metal ion complexes for potential detoxification treatments.

Activatable molecular fluorescence probes for the imaging and detection of ischemic stroke

The real-time, noninvasive, nonionizing, high spatiotemporal resolution, and flexibility characteristics of molecular fluorescence imaging provide a uniquely powerful approach to imaging and monitoring the physiology and pathophysiology of ischemic stroke. Currently, various fluorescence probes have been synthesized with the aim of improving quantitative and quantitative studies of the pathologic processes of ischemic stroke in living animals. In this review, we present an overview of current activatable fluorescence probes for the imaging and diagnosis of ischemic stroke in animal models. We categorize the probes based on their activatable signals from the biomarkers associated with ischemic stroke, and we present representative examples of their functional mechanisms. Finally, we briefly discuss future perspectives in this field.

Sign Response Mechanism of TCA Self-assembled Fluorescence Probe for Cu^2＋ Detection： FRET Evidence by DFT

A new type of self-assembled molecule ON-OFF fluorescence probe for toxic transition metal ions, made up of thiacalix[4]arene, micelle and fluorescence group, has been studied by DFT/TDDFT method combined with experiment spectra. Since the mechanism of the optical quenching signal response of such self-assembled micelle probe has always been a controversial issue of uncertainty, the spatial construction and geometric structures of the functional units of probe in the Cu2＋ ion detecting process were calculated and the mechanism was investigated by the molecular transition orbital pairs method to explore the origination of ON-OFF fluorescence sign response. The results presented that the signal response mechanism of the micelle probe is ascribed to F？rster resonance energy transfer（FRET） which provides new sights different from most of the conclusions by the related research work reported.

Study on Anticoagulation Factor I from Agkistrodon Acutus Venom by Rare Earth Ion Probes

It was observed that rare earth ions (Nd 3+, Sm 3+, Eu 3+, Gd 3+, Tb 3+) have significant quenching effects on the fluorescence of anticoagulation factor I (ACF I). The results of the fluorescence titration of ACF I with rare earth ions demonstrate that ACF I has two RE 3+-binding sites, and the rare earth ions and Ca 2+ bind to ACF I competitively in the two similar sites. The association constants K 1 and K 2 of ACF I with each rare earth ions (Nd 3+, Sm 3+, Eu 3+, Gd 3+, Tb 3+) are close to each other, which indicates the structural similarity of the two binding sites in ACF I. Although the ionic radii of Nd 3+, Sm 3+, Eu 3+, Gd 3+ and Tb 3+ are different, both their K 1 and K 2 are similar, respectively. This reveals the conformational flexibility of the two binding sites in ACF I, which offers a possibility for Ca 2+ to take play in the inducing conformational changes of ACF I and the promoting the binding of ACF I with activated coagulation factor X.

基于荧光素的高选择性Hg^(2+)荧光探针的合成及其光谱性质研究

以荧光素、水合肼及费舍尔氏醛制备了一种新颖的Hg^(2+)荧光探针,其分子结构通过核磁及质谱进行了表征。该探针在金属离子中能够特异性识别Hg^(2+),可应用于对Hg^(2+)的检测。在生命科学及环境科学领域对于Hg^(2+)的准确、快速的实时监测备受关注,本研究在此方面具有潜在的应用价值。

荧光炭点比率探针的构建及可视化快速检测Fe^(3+)

以柠檬酸和邻苯二胺为原料,采用水热法制备了15种炭点,发现通过调控反应的温度和酸的种类,可以改变炭点的荧光颜色和荧光强度。以HNO_(3)调节pH值为2,反应温度为180℃时,获得了绿色炭点,该炭点量子产率高达41.56%;该绿色炭点对Fe^(3+)具有特异荧光响应,且在0.1~1 mM的检测范围中,炭点与Fe^(3+)的浓度具有良好线性关系,其相关系数R^(2)可达0.99795,最低检出限为0.47μM。进一步将该绿色炭点与罗丹明B结合,构建了比率荧光探针,并成功制备了其对应的比色卡纸,实现了可视化快速检测Fe^(3+)浓度。

稀土离子荧光探针的合成及其对铅离子识别的应用

采用鲁米诺(Luminol)、六水硝酸铽(Tb(NO_(3))_(3)·6H_(2)O)和三磷酸腺苷(ATP)等以自组装方法合成了Luminol-Tb-ATP荧光探针.基于稀土离子Tb^(3+)具有斯托克斯位移大和抗光损耗能力强等优势,配位后增强了荧光探针对Pb^(2+)的检测能力,从而构建了高选择性与高灵敏度的荧光探针.运用紫外吸收光谱仪、傅里叶红外光谱仪、荧光光谱仪、Zeta电位仪和拉曼光谱仪等表征了Luminol-Tb-ATP的结构及光学性能.实验结果表明,Pb^(2+)浓度在0~24μmol·L^(-1)范围内与荧光强度呈现出良好的线性关系,相关系数为0.97558,且检测限低至0.13μmol·L^(-1).该探针可被制备成试纸,拓宽了检测场景.

有机硒化合物荧光探针研究进展

荧光探针不仅可以识别目标分析物,而且可以通过荧光信号变化实现定量检测。近年来,含硒有机化合物作为荧光探针已广泛用于检测各种分析物。如金属阳离子和阴离子荧光检测、细胞成像和生物活性监测等。含硒荧光探针与含N-、O-、和S-的荧光探针相比较具有特定优势,其具有高的反应活性,包括氧化、消除以及与亲核试剂和亲电试剂的反应等。此外,含硒的化合物表现出低的氧化还原电位,根据这一性能开发出一系列特定功能的荧光探针,综述了含硒化合物对金属离子、硫醇(RSH)、活性氧物质(ROS)荧光探针的研究进展,并对该领域的发展前景进行了展望。

荧光探针PTAID固态试纸法测定土壤中Pd^(2+)和Cu^(2+)的比较研究

将新型荧光探针PTAID以固态形式用于检测土壤中的钯离子(Pd^(2+))和铜离子(Cu^(2+)),检出限分别为0.63和1.19μmol/L,说明探针PTAID对Pd^(2+)和Cu^(2+)有很高的灵敏度。通过条件优化实验,说明探针PTAID在pH值为4.0~12.0,反应时间为0~15 min内可以快速检测Pd^(2+)和Cu^(2+)。对土壤样品中的Pd^(2+)和Cu^(2+)进行检测,该方法与电感耦合等离子体发射光谱法相比,准确度和精密度均较高,具有响应时间短、灵敏度高、选择性好等优点,在土壤重金属检测方面具有广阔的应用前景。

铜纳米团簇对烧鸡卤水中Fe^(3+)的荧光传感研究

食品中的重金属污染问题日益严重,对人们的生活产生了严重威胁。文章以2-硫代巴比妥酸(TBA)和甘氨酸(Gly)为配体,制备一种新型的具有红色荧光的铜纳米团簇(CuNCs)。以该团簇作为荧光探针,在基于其优异的选择性及抗其他离子干扰能力的基础上,对三价铁离子(Fe^(3+))浓度的最低检出线为3.78μmol/L。将加标回收法应用于烧鸡卤水中Fe^(3+)的荧光检测,其加标回收率在93.5%~104.1%之间,相对标准偏差(relative standard deviation,RSD)均低于5.00%,表明该荧光探针对食品中的Fe^(3+)具有良好的检测前景。

中氮茚衍生物对金属离子选择识别性的研究

比较了Cu2+、Zn2+、Co2+、N i2+、Na+、K+、Ca2+、Mg2+等8种金属离子对所合成的一系列含不同取代基的中氮茚衍生物荧光性能的影响,旨在探明这些中氮茚衍生物对金属离子的选择识别性.发现Cu2+能使其荧光显著猝灭,因此,这些衍生物有望作为识别铜离子的有机荧光材料.

识别细胞内金属离子的有机荧光探针研究进展

金属离子广泛存在于组织细胞和体液中,在人体的生理和病理中发挥着十分重要的作用。金属离子的浓度必须精确控制在一定的范围内,某些离子浓度的微弱变化都将引发人体的疾病。由于细胞是生命活动的基本单位,因此研究各种金属离子对生物体的影响,通过对活体细胞内金属离子的荧光显微成像进行细胞内离子的可视化定量和定性分析引起了人们的极大关注。就近年来人们对识别细胞内金属离子的有机荧光探针与细胞成像研究领域的进展进行了评述。

水热法新型水溶性荧光碳点的制备及其性能研究

以阿拉伯糖和磷酸酪蛋白肽进行水热反应,制备水溶性多色荧光碳点,利用透射电子显微镜(TEM)、紫外吸收光谱(UV)、荧光光谱(FL)、红外光谱(FTIR)和X射线衍射(XRD)等对所制备碳点的粒径大小、吸收光谱、发光性质、表面基团等进行表征,并考察了其性能和对不同金属离子的识别作用。结果表明:制备的荧光碳点平均粒径为4.62 nm,其紫外最大吸收波长为281 nm,XRD峰值约为21°,可在紫外灯下发出明亮的荧光,最大发射波长为414 nm,且呈荧光多元发射。红外光谱分析表明存在—COOH,—NH2和—OH基团。该荧光碳点具有良好的性能,且对Cu2+和Fe3+有较强的选择性识别作用,其原因可能是荧光碳点的聚合导致粒径增大从而使荧光强度减弱。该碳点有望作为荧光探针用于检测分析和生物成像等领域。

水溶性苝类荧光探针的合成及对Pb^2＋离子的识别

以苝四酸酐为原料合成了作为铅荧光探针的一种新型水溶性荧光衍生物N,N'-二谷氨酸铵盐-3,4,9,10-苝四羧酸二酰亚胺(PTCDG),其结构已经1H NMR和IR证实。研究了PTCDG及PTCDG与金属离子(M)络合物(PTCDG/M)的光谱性质和PTCDG对金属离子的识别性能。结果表明,PTCDG在水溶液中能与Pb2+有较强的螯合作用,两者络合比为1∶1,Pb2+可有效淬灭PTCDG的荧光且PTCDG对Pb2+识别作用不受Mn2+、Mg2+、Zn2+、Ni 2+、Ca2+、Co2+、Na+、K+、Ba2+、Hg2+等金属离子干扰。本文还对PTCDG与金属离子作用的荧光变化机理做了探讨。

CdSe量子点的合成及其在重金属离子检测中的应用

以3-巯基丙酸(3-MPA)为修饰剂合成了水溶性CdSe量子点,优化了合成条件,并以其为荧光探针建立了水样中Pb^(2+)和Hg^(2+)的检测方法。实验结果表明:在n(Se)∶n(Cd^(2+))为1∶6、n(Se)∶n(Na BH4)为1∶3、n(Cd^(2+))∶n(3-MPA)为1∶6、反应p H为11、回流温度为100℃、回流时间为60 min的优化条件下合成的量子点荧光性能较优;量子点的荧光猝灭强度与Pb^(2+)或Hg^(2+)的质量浓度呈良好的线性关系,线性范围分别为0.005~10 mg/L和0.001~1 mg/L,检出限分别为0.003 mg/L和0.001 mg/L,相对标准偏差分别为1.23%和1.29%,可应用于实际水样中Pb^(2+)和Hg^(2+)的检测。

重金属离子荧光探针的应用及研究进展

荧光探针因具有高灵敏度、高选择性、使用便捷、成本低廉、样品不需要预处理等优点而备受关注,如今已成为一种重要的荧光传感分析方法。对荧光探针的识别机理、各种荧光探针分子在离子检测方面的应用作了简要介绍。介绍了卟啉类、罗丹明类、萘酰亚胺类、喹啉类、香豆素类和荧光纳米材料类等不同类型的荧光探针在重金属离子检测领域的研究与应用情况;阐述了重金属离子荧光探针的研究方向和前景,对其未来的发展趋势作了进一步的展望。

过渡金属离子荧光探针——2,6-二氨基吡啶的研究

研究了2,6-二氨基吡啶(DAPD)与金属离子作用前后的荧光光谱和吸收光谱。结果表明,在加入过渡金属离子后,其发射光谱和吸收光谱产生红移,且光谱强度随金属离子浓度的加大而增强;但加入K+,Na+,Mg2+,Ca2+,Pd2+等金属离子后,DAPD无响应。根据Irving-Williams顺序,以过渡金属中络合能力较强的Cu2+为代表,考察了其对DAPD吸收光谱及荧光光谱的影响。Cu2+浓度在2.5×10-7～3.5×10-6mol/L范围内与荧光强度呈线性关系,求算出DAPD与Cu2+的结合比为2∶1。比较了不同的过渡金属离子对DAPD荧光强度影响的强弱,即Cu2+>Zn2+>Co2+>Ni2+>Ag+,并探讨了荧光机理。结合其结构特点,认为DAPD是可逆的、灵敏的过渡金属离子荧光探针。

基于Schiff碱结构的香豆素类荧光探针的合成及对Mg2+的识别

以2-氨基苯并咪唑和7-羟基香豆素为基本原料制备了Mg^2+荧光探针,采用核磁共振谱与质谱等手段对产物的构成进行了详尽的表征。然后通过荧光发射光谱的测试分析,了解了探针的各项性能。结果显示,在MeOH∶H2O=1∶1(V∶V)混合溶液中探针对Mg^2+具有良好的选择性而不受其他金属离子(Ca^2+、Na^+、Li^+、K^+、Cu^2+、Fe^3+、Zn^2+、Ni^2+、Mn^2+、Ba^2+、Cd^2+、Cr^3+、Ag^+、Al^3+、Hg^2+、Co^2+、Pb^2+)的干扰。探针对Mg2+具有可逆性,其检测限为7.3×10^-8mol/L。通过对探针的性能研究可知该探针能够完成对Mg^2+的检测,在生命医学、环境科学及分析化学等领域具有潜在的应用价值。

氮硫掺杂碳量子点荧光探针检测Fe^(3+)和Hg^(2+)

为了实现水溶液中Fe^(3+)和Hg^(2+)的快速简捷检测,以柠檬酸和硫脲为前驱体,采用一步水热法合成硫、氮共掺杂碳量子点荧光探针。通过透射电镜、傅里叶红外光谱、X射线光电子能谱、荧光分光光度计和紫外-可见吸收光谱分析合成碳点的形貌特征及荧光性能。结果表明:N—S—CDs的平均粒径为8 nm,分布均匀;表面富有各种官能团,具有良好的水溶性;在紫外灯照射下发出强烈的蓝色荧光,荧光量子产率高达36.8%;随激发波长增大,N—S—CDs发射峰荧光强度先增大后减小,在440 nm处荧光强度达到最高,并且其发射峰随着激发波长发生明显红移。N—S—CDs对Fe^(3+)和Hg^(2+)具有较高选择性;Fe^(3+)浓度在40~130μmol/L,Hg^(2+)浓度40~80μmol/L,荧光强度与2种离子呈良好线性关系,线性回归方程分别为F_(0)/F=0.02132c_(Fe^(3+))+0.34945和F_(0)/F=0.18611c_(Hg^(2+))-6.27114;最低检出限分别为1.4、0.16μmol/L;将N—S—CDs用于自来水和湖水的实样分析,可有效检测自来水和湖水中Fe^(3+)和Hg^(2+)。Fe^(3+)的定量回收率为97.16%~103.62%,Hg^(2+)的定量回收率为93.58%~101.22%。