检测汞离子的比色-荧光双通道探针的设计合成及应用

以7-羟基吩恶嗪酮(试卤灵)为荧光团、硫代甲酸苯酯为汞离子(Hg²⁺)识别基团,经一步简单有机合成反应,制备了比色-荧光双通道探针NMP。采用核磁共振氢谱(¹H NMR)、核磁共振碳谱(¹³C NMR)和高分辨率质谱(HRMS)表征了探针结构,利用吸收光谱和荧光发射光谱测试了探针对Hg²⁺的选择性和灵敏度。光谱测试结果表明,探针对Hg²⁺具有较好的选择性和检测灵敏度,检出限(3σ)为17 nmol/L。反应溶液由淡黄色变为紫红色,可对溶液中Hg²⁺进行比色检测,并可用于实际水样中Hg²⁺的检测。采用CCK-8法测试了探针的细胞毒性,结果表明,在探针浓度低于10μmol/L时,细胞存活率高于90%。共聚焦荧光显微成像结果表明,探针具有较好的细胞通透性,可对细胞内Hg²⁺进行荧光成像。     

汞离子荧光、比色传感器

基于主客体识别的汞离子比色、荧光传感器由于使用方法简单、灵敏度高、不需要昂贵仪器等优势,受到了越来越多的关注。本文综述了近年来汞离子比色和荧光传感器的研究进展。本文根据作用机理将汞离子比色、荧光传感器分成三类,即通过特殊反应识别汞离子的传感器,通过配位作用识别汞离子的传感器以及基于纳米材料的汞离子传感器。其中通过特殊反应识别的传感器根据具体反应类型又可分成汞离子诱导的罗丹明上的内酰胺环开环型、汞离子与含硫(硒)的受体发生脱硫(硒)反应使受体氧化或关环型、汞离子与受体发生加汞化反应型和汞离子使受体发生汞离子催化的化学反应型这四类。本文对这些类型的汞离子传感器从设计原理、识别性能和机理等方面进行了介绍,并展望了该领域的研究方向。     

基于银/铂纳米模拟酶表面修饰的铜离子比色检测方法研究

通过对银/铂纳米簇(Ag/Pt NCs)的表面修饰调控其催化活性,建立了一种高灵敏的比色法检测Cu2+.巯基丙酸能够抑制Ag/Pt NCs的催化活性,而巯基丙酸与Cu2+作用后,将导致上述抑制作用减弱.基于上述原理,通过测量Ag/Pt NCs 催化TMB-H2O2反应产生的显色信号,可以实现Cu2+的比色检测.本方法检测Cu2+的线性范围为10～100 nmol/L,检出限(3σ)为5.0 nmol/L.将本方法应用于实际水样中Cu2+的检测,结果表明,本方法具有操作简单、成本低、灵敏度高、特异性好等优点.     

基于小分子的铜离子与汞离子双识别荧光探针

铜离子在不同细胞生理过程中作为催化辅助因子起着很重要的作用,但是体内铜离子浓度出现异常也会导致疾病甚至死亡。与铜离子相比,汞离子是各种重金属污染物中最普遍、最危险的一种。因此,对它们高灵敏度、高选择性检测具有非常重要的意义。荧光探针法由于具有灵敏度高、快速便捷、可视化和原位无损检测等优点而成为Cu²⁺与Hg²⁺离子重要的检测手段之一。本文总结了近几年基于小分子Cu²⁺和Hg²⁺离子双识别荧光探针的设计合成、性能及其在分析方面的研究与最新进展,并展望了此类荧光探针未来的研究与发展方向。     

荧光碳量子点的绿色合成及高灵敏高选择性检测汞离子

本实验以苹果汁为原料,通过一步水热法合成得到了水溶性好及稳定性高的蓝色荧光碳量子点。研究发现Hg2+对碳量子点荧光有良好的猝灭作用,从而建立了一种快速检测Hg2+的新方法。实验发现在pH 7.0磷酸盐缓冲介质中碳量子点荧光猝灭强度与Hg2+浓度在5~100 nmol/L和1~50μmol/L范围内呈线性关系,检出限为2.3 nmol/L(S/N=3)。本方法可用于实际水样中Hg2+的测定。     

纳米光学传感器用于检测汞离子

汞离子是毒性最大的重金属之一,对环境和人体都会造成严重的不良影响,开发能够快速检测环境中汞离子的分析方法引起了越来越多的关注。纳米材料由于其优良的光学性能和良好的稳定性,被广泛用于环境中汞离子的检测。本文主要综述了近年来一些代表性的基于纳米材料的汞离子荧光、比色传感器。根据纳米材料的不同,将这些传感器分为基于金、银、碳和硅基材料,以及量子点、有机纳米颗粒和其他纳米基材料的荧光、比色传感器,并分别从设计原理、识别性能和实际应用等方面对这些传感器进行了描述和讨论。最后对该领域的研究和发展提出了展望。     

基于免疫磁球的埃博拉病毒糖蛋白高灵敏比色检测

用免疫磁球捕获埃博拉病毒糖蛋白,与生物素化抗体形成免疫夹心复合物,然后链霉亲和素标记辣根过氧化物酶(SA-HRP)催化3,3',5,5'-四甲基联苯胺(TMB)进行显色,通过370 nm处吸光度对病毒糖蛋白进行定量。对免疫磁球进行了免疫荧光表征,通过对照实验验证方法的可靠性,并对检测条件进行了优化。结果表明,吸光度与病毒糖蛋白浓度在1.0~25.0 ng/m L内呈线性关系,检出限达到0.18 ng/m L。该方法重现性较好,特异性好,抗干扰能力强,可实现复杂样品中埃博拉病毒的检测。     

基于荧光树状聚合物的高灵敏化学反应型汞离子传感器

以2,4-二氯苯硫酚为单体, 通过“一步法”合成了平均分子量为10.910 kD的荧光树状超支化聚苯硫醚(HPPS). 通过亲核取代和水解反应对HPPS进行了外围氨基修饰, 通过偶氮共价键使HPPS与氨基硫脲小分子相连, 制备出了高灵敏度树状聚合物基多位点反应型汞离子传感器. 基于汞离子与氨基硫脲脱硫关环反应和超支化聚苯硫醚对光信号的放大传递作用, 传感器对汞离子有灵敏的荧光响应信号, 线性范围为2.5～100 nmol/L, 检出限为0.46 nmol/L. 并利用分子模拟计算对反应识别机理进行了讨论.     

聚多巴胺包覆的钙钛矿修饰电极用于电化学检测水中铜、汞和铅离子

通过水热法合成具有钙钛矿结构的LaCo0.21Ni1.59O3,将聚多巴胺(PDA)包覆在LaCo0.21Ni1.59O3表面,得到PDA@LaCo0.21 Ni1.59 O3复合材料.利用钙钛矿优异的电催化性能和PDA丰富的胺基基团,将复合材料修饰在玻碳电极(GCE)表面,构建了一种新型电化学传感平台(PDA@LaC...     

基于多巴胺-量子点的比色免疫分析法对甲胎蛋白的高灵敏检测

基于抗原抗体识别特异性,以多巴胺-Mn/ZnS量子点(DA-QDs)为反应媒介,紫外可见分光光度计为检测手段,采用柠檬酸钠还原法制备金纳米颗粒(AuNPs),其表面用辣根过氧化物酶(HRP)和羊抗小鼠免疫球蛋白G (IgG)修饰获得功能化二抗(IgG-AuNPs-HRP)作为信号放大标签,构建一种简便高灵敏的检测方法....     

Highly selective and sensitive paper-based colorimetric sensor using thiosulfate catalytic etching of silver nanoplates for trace determination of copper ions

A novel, highly selective and sensitive paper-based colorimetric sensor for trace determination of copper (Cu²⁺) ions was developed. The measurement is based on the catalytic etching of silver nanoplates (AgNPls) by thiosulfate (S₂O₃²⁻). Upon the addition of Cu²⁺ to the ammonium buffer at pH 11, the absorption peak intensity of AuNPls/S₂O₃²⁻ at 522 nm decreased and the pinkish violet AuNPls became clear in color as visible to the naked eye. This assay provides highly sensitive and selective detection of Cu²⁺ over other metal ions (K⁺, Cr³⁺, Cd²⁺, Zn²⁺, As³⁺, Mn²⁺, Co²⁺, Pb²⁺, Al³⁺, Ni²⁺, Fe³⁺, Mg²⁺, Hg²⁺ and Bi³⁺). A paper-based colorimetric sensor was then developed for the simple and rapid determination of Cu²⁺ using the catalytic etching of AgNPls. Under optimized conditions, the modified AgNPls coated at the test zone of the devices immediately changes in color in the presence of Cu²⁺. The limit of detection (LOD) was found to be 1.0 ng mL⁻¹ by visual detection. For semi-quantitative measurement with image processing, the method detected Cu²⁺ in the range of 0.5–200 ng mL⁻¹(R² = 0.9974) with an LOD of 0.3 ng mL⁻¹. The proposed method was successfully applied to detect Cu²⁺ in the wide range of real samples including water, food, and blood. The results were in good agreement according to a paired t-test with results from inductively coupled plasma-optical emission spectrometry (ICP-OES).     

基于金纳米棒刻蚀比色法检测铁、铜离子

采用种子生长法制备金纳米棒(AuNRs)以构建光学传感器,用于Fe³⁺和Cu²⁺的高选择性快速可视化检测。在酸性环境中,Fe³⁺和Cu²⁺通过与KI溶液反应,将I-氧化成I2。I2刻蚀AuNRs,导致其纵向表面等离子体共振(LSPR)吸收峰蓝移,从而实现对Fe³⁺和Cu²⁺的检测。结果表明,反应温度为50℃时,添加0.8 mL 0.1 mol·L^-1 HCl、2 mL AuNRs生长液和20 mmol·L^-1 KI溶液,与2 mL 500 μmol·L^-1 Fe³⁺或30 μmol·L^-1 Cu²⁺反应25或90 min,可将AuNRs刻蚀至LSPR吸收峰消失。该方法对Fe³⁺和Cu²⁺检测具有高选择性和准确性,对于Fe³⁺、Cu²⁺共存体系的检测,可通过加入适量F-与Fe³⁺生成配合物[FeF₆]^3-完成对Fe³⁺的化学掩蔽,消除Fe³⁺的干扰,实现共存体系中Cu²⁺的准确检测。     

基于金纳米棒刻蚀比色法检测铁、铜离子

采用种子生长法制备金纳米棒(AuNRs)以构建光学传感器,用于 Fe³⁺和 Cu²⁺的高选择性快速可视化检测。在酸性环境中,Fe³⁺和 Cu²⁺通过与 KI溶液反应,将 I^-氧化成 I₂。I₂刻蚀 AuNRs,导致其纵向表面等离子体共振(LSPR)吸收峰蓝移,从而实现对Fe³⁺和Cu²⁺的检测。结果表明,反应温度为50℃时,添加0.8 mL 0.1 mol·L^-1 HCl、2 mL AuNRs生长液和20 mmol·L^-1 KI溶液,与 2 mL 500 μmol·L^-1 Fe³⁺或 30 μmol·L^-1 Cu²⁺反应 25或 90 min,可将 AuNRs刻蚀至 LSPR 吸收峰消失。该方法对 Fe³⁺和 Cu²⁺检测具有高选择性和准确性,对于 Fe³⁺、Cu²⁺共存体系的检测,可通过加入适量 F-与 Fe³⁺生成配合物[FeF₆]3^-完成对 Fe³⁺的化学掩蔽,消除Fe³⁺的干扰,实现共存体系中Cu²⁺的准确检测。     

一例水溶液中识别铜离子的染料探针

通过罗丹明B与乙二胺反应生成的中间体合成了一例可以对铜离子进行比色检测的探针R-Cu.R-Cu可以实现对在HEPES(5 mmol/L;pH 7.4)溶液中Cu2+的比色可视化识别,加入Cu2+后,R-Cu的吸收明显增强,呈现出罗丹明B的紫红色.探针对Cu2+具有较高的选择性和灵敏性,对其他常见的金属离子具有较强的抗干扰能力.该探针可以在较宽的特别是近中性pH环境下有效检测Cu2+,最低检出限为2.70×10?7 mol/L.     

CE combined with rolling circle amplification for sensitive DNA detection

Here we describe an assay which combines CE with rolling circle amplification (RCA) for sensitive DNA detection and quantification. RCA is an isothermal DNA replication technique that generates a long ssDNA with tandem repeats. It requires simpler temperature control in reaction and offers higher sequence specificity and greater quantitation capability compared to other amplification technologies. In this study, RCA amplified the DNA target via a circular template, and the product was digested into monomers for CE analysis. Less than 2 fmol of the DNA target could easily be detected using this RCA-CE assay and the assay has a dynamic range of two orders of magnitudes. Moreover, simultaneous detection of both the target DNA and the internal standard was achieved by designing two padlock probes with different sizes, which could significantly improve the quantification accuracy. The RCA-CE assay is easy to perform, readily adaptable for detection of multiple targets because of the high resolution power of CE, and is compatible with other applications employing RCA as a signal amplification tool. Additionally, this assay can be used with a capillary array system to perform sensitive, high-throughput genetic screening.     

Simultaneous voltammetric analysis of lead,copper and mercury ions by carbon paste electrode based on 1-(3-aminopropyl) imidazole modified polymer

In this study, a carbon paste electrode modified with a novel 1-(3-aminopropyl) imidazole functionalised crosslinked chlorosulfonated poly(styrene)-divinyl benzene polymer was used for selective and sensitive determination of the trace amounts of Pb²⁺, Cu²⁺ and Hg²⁺ ions by square wave anodic stripping voltammetry. The effect of some parameters such as paste composition, pH, preconcentration time, reduction potential and time, type of supporting electrolyte and potential scan rate on the determination of metal ions were investigated to find the optimal conditions. The effective open-circuit accumulation of the studied metal ions was succeeded only by the modification of the carbon paste electrode with functional polymer. For 6 min open-circuit preconcentration, the detection limit of Pb²⁺, Cu²⁺ and Hg²⁺ was found to be 5, 9 and 14 µgL^?1, respectively at 100 mVs^?1. The results confirmed that the lower concentration levels of these trace metal ions can be determined with the increase of preconcentration time and/or potential scan rate. Good detection limits and large dynamic concentration ranges were also obtained for their binary and ternary mixtures. The optimised method was successively applied to determine the concentration of Pb²⁺, Cu²⁺ ions in the tap water sample and Cu²⁺ ion in the waste water sample in the presence of possible interfering species (RSD<1%, recoveries 96–110% for 4 min preconcentration).     

Ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon mediated circular strand displacement polymerization and hyperbranched rolling circle amplification

Using a cascade signal amplification strategy, an ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon (MB) mediated circular strand displacement polymerization (CSDP) and hyperbranched rolling circle amplification (HRCA) was proposed. The hybridization of MB probe to target DNA resulted in a conformational change of the MB and triggered the CSDP in the presence of bio-primer and Klenow fragment (KF exo⁻), leading to multiple biotin-tagged DNA duplex. Furthermore, the HRCA was implemented to product amounts of double-stranded DNA (ds-DNA) fragments using phi29 DNA polymerase via biotin-streptavidin interaction. After the product of HRCA binded numerous biotinylated detection probes, an ultrasensitive electrochemical readout by further employing the streptavidin-alkaline phosphatase. The proposed biosensor exhibited excellent detection sensitivity and specificity with a log-linear response to target DNA from 0.01 fM to 10 pM as low as 8.9 aM. The proposed method allowed DNA detection with simplicity, rapidness, low cost and high specificity, which might have the potential for application in clinical molecular diagnostics and environmental monitoring.     

Peroxidase-like catalytic activity of copper ions and its application for highly sensitive detection of glypican-3

Glypican-3 (GPC3) might be used as new biomarker of liver cancer for the development of new diagnostic methods. The most commonly used methods for protein detection are based on natural enzymes, which are easily affected by environmental conditions and suffer from the rigorous preparation conditions. Thus, the development of new enzyme mimetics with high and stable catalytic activity is of great significance in diagnostic applications. In this paper, copper ions (Cu²⁺) was found to possess the peroxidase-like catalytic activity, which can catalyze H₂O₂-mediated oxidation of peroxidase substrate and obtain the oxidation product with color change. This catalytic activity is much more stable than other nanomaterials based peroxidase mimetics, and can significantly increase by increasing the concentration of H₂O₂. It is worth mentioning that the absorbance signal induced by 5 nM Cu²⁺ can be easily detected. This Cu²⁺-catalyzed reaction can be also applied in the detection of GPC3 by using the anti-GPC3 antibody functionalized CuO NPs, which can release the Cu²⁺ by dissolved in HCl solution. This method permits detection of as low as 0.26 pg mL⁻¹ GPC3. This sensitivity is about one or several magnitudes higher than that of ELISA or other peroxidase mimetics based methods. The high catalytic activity of Cu²⁺ and the signal amplification process of CuO NPs into high amount of Cu²⁺ also make this method more simple and effective.     

Hyperbranched rolling circle amplification as a rapid and sensitive method for species identification within the Cryptococcus species complex

The Cryptococcus species complex contains two closely related basidiomycetous yeasts: Cryptococcus neoformans and C. gattii, which cause cryptococcosis in humans and other animals. The species and varieties are characterized, by different clinical, epidemiological, biochemical and molecular features. The currently used identification methods are either time-consuming or not anymore commercially available. However, a rapid, sensitive and robust assay for the detection of these pathogens is vital for early diagnosis and appropriate treatment decisions. To overcome those limitations, four padlock probes targeting species-specific single nucleotide polymorphisms at the internal transcribed spacers (ITSs) of the RNA gene locus were developed and applied during isothermal hyperbranched rolling circle amplification (HRCA). The probes were tested against 99 samples, including 94 clinical cryptococcal cultures, three closely related Cryptococcus species, and two clinical specimens. The use of the padlock probes and the combination of probe signal amplification by HRCA provided a quick and sensitive assay for the accurate identification of C. neoformans var. grubii, C. neoformans var. neoformans and C. gattii. HRCA was also useful to detect hybrids, when they were heterozygous at the ITS locus. The HRCA results were in agreement with previous genotyping data based on PCR fingerprinting, amplified fragment length polymorphism and ITS sequencing.