Cascade reaction-based fluorescent probe for detection of H2S with the assistance of CTAB micelles

We report a turn-on fluorescent probe for H₂S through a cascade reaction using a new trap group 4-(bromomethyl)benzoate, based on excited-state intramolecular proton transfer (ESIPT) sensing mechanism. The probe showed good selectivity and high sensitivity towards H₂S and it was capable of detecting and imaging H₂S in living HeLa cells, indicating its potential biological applications.     

基于磺酸酯的荧光探针用于活细胞内过氧化氢的成像检测

基于过氧化氢（H2O2）特异性催化水解磺酸酯,设计合成了新型绿色荧光探针：荧光素二磺酸酯（FS—1）和二氯荧光素二磺酸酯（FS-2）两种螺环内酯型化合物,用于活细胞内过氧化氢的检测．探针结构由元素分析、IR、^1H NMR及^13C NMR表征．实验表明：探针FS-1和FS-2在模拟生物体系中检测过氧化氢具有良好的选择性和灵敏度,且线性范围较宽．细胞成像显示：探针FS-1和FS-2用于PMA刺激或外加不同浓度H2O2孵育的小鼠腹膜巨噬细胞均呈现明亮的绿色荧光,且能对细胞内H2O2微摩尔级浓度变化产生响应,证明两探针均具有良好的膜渗透性、高的选择性及良好的灵敏度．该方法的建立对研究生物体内H2O2的产生,H2O2导致的各种疾病机制及H2O2介导的信号转导途径具有重要的理论及实际意义．     

A fluorescent probe for Hg2+sensing in solutions and living cells with a wide working pH range简

In this paper, 2-carboxybenzaldehyde rhodamine B thiohydrazine(1) was synthesized and developed as a fluorescent probe to recognize Hg2+in DMF/H2 O(1:9, v/v) solution with high selectivity. The probe can be applied to the quanti?cation of Hg2+with a linear concentration range covering from 1.0×10-7mol/L to 1.0×10-5mol/L(R2= 0.9985) and a detection limit of 4.2×10-8mol/L. The experiment results show that the response of probe 1 to Hg2+is pH-independent in a wide range from 4.0 to 9.0. Moreover, the probe 1 exhibits excellent selectivity toward Hg2+over other common metal cations. Most importantly, the probe can be employed to monitor Hg2+in living cells using fluorescent imaging technique with satisfied results.     

A 1,8-naphthalimide-derived turn-on fluorescent probe for imaging lysosomal nitric oxide in living cells

Nitric oxide has played an important role in many physiological and pathological processes as a kind of important gas signal molecules. In this work, a new fluorescent probe LysoNO-Naph for detecting NO in lysosomes based on 1,8-naphthalimide was reported. LysoNO-Naph has sub-groups of o-phenylenediamine as a NO reaction site and 4-(2-aminoethyl)-morpholine as a lysosome-targetable group. This probe exhibited good selectivity and high sensitivity (4.57 μmol/L) toward NO in a wide pH range from 4 to 12. Furthermore, LysoNO-Naph can be used for imaging NO in lysosomes in living cells.     

一种基于丹磺酰胺染料的高选择性汞(Ⅱ)离子荧光探针

对人类健康和社会环境而言,汞离子被认为是毒性最大的金属离子之一.本文设计、合成了一种新型基于丹磺酰胺染料的荧光探针,并研究了其对金属阳离子的识别性质.研究结果表明:该荧光探针在水溶液中,对汞离子具有高度的选择性和良好的灵敏度,且不受其它金属阳离子的干扰.该探针对汞离子的检测限可以达到2.1×10-8 mol/L.该探针极低的检测限和良好的水溶性表明其可用于活细胞中检测汞离子.生物成像实验证实该探针具有良好的细胞膜透性和生物相容性.     

A benzothiazole-based fluorescent probe for thiol bioimaging

This study reports a benzothiazole-based fluorescent probe with simple structure for thiols. This probe exhibited high on/off signal ratios and good selectivity toward thiols over other analytes, and was successfully applied to the imaging of thiols in living cells.     

Two-photon fluorescent probe for cadmium imaging in cells

A novel two-photon excited fluorescent probe for cadmium (named as TPCd) was designed and synthesized utilizing a prodan (6-acetyl-2-methoxynaphthalene) derivative as the two-photon fluorophore and an o-phenylenediamine derivative as the Cd(2+) chelator, which possessed favorable photophysical properties and good water-solubility. The probe was designed with a photoinduced electron transfer (PET) mechanism and thus was weakly fluorescent itself. After binding with Cd(2+) which blocked the PET process, the fluorescence intensity of the probe was enhanced by up to 15-fold under one-photon excitation (OPE) and 27-fold under two-photon excitation (TPE), respectively. The two-photon action cross-section (Φδ) of the TPCd-Cd complex at 740 nm reached 109 GM compared to 3.6 GM for free TPCd, indicating the promising prospect of the probe in two-photon application. TPCd chelated Cd(2+) with 1 : 1 stoichiometry, and the apparent dissociation constant (K(d)) was 6.1 × 10(-5) M for the one-photon mode and 7.2 × 10(-5) M for the two-photon mode. The probe responded to Cd(2+) over a wide linear range from 0.1 to 30 μM with a detection limit of 0.04 μM. High selectivity of the probe towards Cd(2+) was acquired in Tris-HCl/sodium phosphate buffer. The probe was pH-independent in the biologically relevant pH range and non-toxic to living cells at reasonable concentration levels, warranting its in vivo applications. Through two-photon microscopy imaging, the probe was successfully applied to detect Cd(2+) uptake in living HepG2 cells.     

A highly selective and sensitive nanoprobe for detection and imaging of the superoxide anion radical in living cells

A novel fluorescent nanoprobe with high sensitivity and selectivity for detection and imaging of the superoxide anion radical O(2)(·-) in living cells was designed and synthesized by a simple self-assembly method based on 2-chloro-1,3-dibenzothiazoline-cyclohexene (DBZTC) and Ag@SiO(2) core-shell nanoparticles.     

High efficient probes with Schiff base functional receptors for hypochlorite sensing under physiological conditions

A series of novel and convenient fluorescent probes with Schiff base functionality were presented for direct detection of OCI via the irreversible OCl-promoted oxidation and hydrolyzation reaction in formation of the ring-opened product, fluorescein. Prominent high sensitivity, selectivity and antiinterference OCl-induced fluorescence and color change over a wide range of tested metal ions performance were observed for each probe under physiological conditions, thus making the probes well suitable for sensing of OCl in living cells.     

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。     

Sensitive and selective off-on rhodamine hydrazide fluorescent chemosensor for hypochlorous acid detection and bioimaging

A rhodamine 6G hydrazide fluorescent chemosensor was prepared for the rapid HOCl detection in aqueous media. The system makes good use of the irreversible HOCl-mediated selective oxidation reaction to generate fluorescent response proportional to the amount of HOCl in neutral buffer. This probe exhibits great photostability, high sensitivity, and good selectivity for HOCl over other reactive species and most of the common metal ions. Furthermore, the probe is cell membrane permeable, and its applicability has been successfully demonstrated for fluorescence imaging of both exogenous and endogenous HOCl within living cells. Cytotoxicity assays prove that this probe is almost nontoxic to the cultured cell lines under the experimental conditions.     

A unique approach to development of near-infrared fluorescent sensors for in vivo imaging

Near-infrared (NIR) fluorescent sensors have emerged as promising molecular tools for imaging biomolecules in living systems. However, NIR fluorescent sensors are very challenging to be developed. Herein, we describe the discovery of a new class of NIR fluorescent dyes represented by 1a/1c/1e, which are superior to the traditional 7-hydroxycoumarin and fluorescein with both absorption and emission in the NIR region while retaining an optically tunable hydroxyl group. Quantum chemical calculations with the B3LYP exchange functional employing 6-31G(d) basis sets provide insights into the optical property distinctions between 1a/1c/1e and their alkoxy derivatives. The unique optical properties of the new type of fluorescent dyes can be exploited as a useful strategy for development of NIR fluorescent sensors. Employing this strategy, two different types of NIR fluorescent sensors, NIR-H(2)O(2) and NIR-thiol, for H(2)O(2) and thiols, respectively, were constructed. These novel sensors respond to H(2)O(2) or thiols with a large turn-on NIR fluorescence signal upon excitation in the NIR region. Furthermore, NIR-H(2)O(2) and NIR-thiol are capable of imaging endogenously produced H(2)O(2) and thiols, respectively, not only in living cells but also in living mice, demonstrating the value of the new NIR fluorescent sensor design strategy. The new type of NIR dyes presented herein may open up new opportunities for the development of NIR fluorescent sensors based on the hydroxyl functionalized reactive sites for biological imaging applications in living animals.     

Solvent-dependent turn-on probe for dual monitoring of Ag and Zn in living biological samples

A novel, solvent-dependent “off–on” probe with benzoylthiourea moiety as the functional receptor and fluorescein as the fluorophore was designed for monitoring of Ag⁺ in EtOH–H₂O (2:8, v/v) solution and Zn²⁺ in CH₃CN–H₂O (2:8, v/v) solution at physiological range with sufficient selectivity and sensitivity. The Ag⁺ promoted desulfurization of thiosemicarbazide functionality in formation of the 1,3,4-oxadiazole and the coordination of Zn²⁺ to the O atom and N atom of the spoirolactam moiety and the S atom of the benzoylthiourea moiety were investigated to be the power that promoted the fluorescent enhancement. This probe was tested highly suitable for mapping Ag⁺ and Zn²⁺ in living human osteosarcoma MG-63 cells and microbial cell–EPS–mineral aggregates, thus, providing a wonderful candidate for tracking Ag⁺ and Zn²⁺ in biological organisms and processes.     

A novel fluorescent probe for formaldehyde based-on monomer-excimer conversion and its imaging in live cells

A novel fluorescent probe was developed for formaldehyde, which can be synthesized by one-step Buchwald–Hartwig reaction. When hydrazino-group of probe reacted with formaldehyde, hydrophobic reaction product aggregates into nanoparticles and results in the blue fluorescence due to the monomer-excimer effect. With enough sensitivity, high selectivity, good stability in physiological pH range and excellent biocompatibility, this probe can image formaldehyde in living cells.     

基于1,8-萘酰亚胺的半胱氨酸荧光探针的合成及在生物成像方面的应用

设计合成了一种用于检测半胱氨酸的新型荧光探针乙二醛(N-羟乙基-1,8-二甲酰亚胺-4-萘基)单腙(NAD),该荧光探针对半胱氨酸表现出较高的灵敏度和选择性.当半胱氨酸加入NAD溶液中,会形成分子内氢键,抑制C■N的异构化,导致荧光增强.此外,探针NAD可应用于细胞内半胱氨酸的检测,表明该类型探针在生物检测应用方面具有较大的潜力.     

2-[3-氰基呋喃-2(5H)-亚基]丙二腈衍生物的合成及其对Pd2+的识别

通过两步反应合成了一种2-(3-氰基呋喃-2(5H)-亚甲基)丙二腈衍生物TCF-Pyn,该化合物在MeCN/磷酸缓冲容溶液(PBS)(V∶V=2∶8,PBS 2×10^-2 mol/L,pH=7.4)混合溶液中能高选择性荧光"OFF-ON"识别Pd²⁺,发射波长达到近红外区(653 nm).该探针具有较好的抗干扰能力、较宽的pH适用范围(3~8)和较低的检测限(6.92μmol/L).应用研究表明,TCF-Pyn能检测真实水样中的Pd²⁺,并可对活细胞中的Pd²⁺进行荧光成像.     

用于谷胱甘肽检测的新型罗丹明衍生物荧光探针EI北大核心CSCD

合成了一种反应型近红外荧光探针N-Rh-GSH,该探针以罗丹明衍生物为荧光母体,通过与谷胱甘肽(GSH)作用触发螺环的开关来实现信号的响应,其开环释放的荧光产物具有760 nm的近红外发射波长。细胞实验表明,该探针可实现对活细胞中GSH的成像。     

A novel near-infrared fluorescent probe was synthesized and its application in imaging of living cells

A novel near-infrared fluorescent probe, IR-736, was synthesized and applied to living cells. The probe exhibited good response fluorescent characteristic, and cells experiments showed the probe had high affinity and without apparent cytotoxicity. Fluorescent image experiments in living L929 cells, MCF-7 cells, HepG2 cells, further demonstrated its potential applications in biological systems. The probe effectively prevented the influence of autofluorescence and native cellular species in biological systems. It also exhibited good photostability, and excellent cell membrane permeability.     

Synthesis, crystal structure and living cell imaging of a Cu(2+)-specific molecular probe

We report the development of a rhodamine chromene-based fluorescence probe to monitor the intracellular Cu(2+) level in living cells. The new fluorescent probe exhibits a fluorescence response towards Cu(2+) under physiological conditions with high sensitivity and selectivity, and facilitates the naked-eye detection of Cu(2+). The fluorescence intensity was significantly increased by about 40-fold with 10 equiv. of added Cu(2+).     

Kinetic analysis of superoxide anion radical-scavenging and hydroxyl radical-scavenging activities of platinum nanoparticles

There are few reports on the physiological effects of metal nanoparticles (nps), especially with respect to their functions as scavengers for superoxide anion radical (O2(.-)) and hydroxyl radical (.OH). We tried to detect the scavenging activity of Pt nps using a hypoxanthine-xanthine oxidase system for O2(.-) and using a Fenton and a UV/H2O2 system for .OH. Electron spin resonance analysis revealed that 2 nm particle size Pt nps have the ability to scavenge O2(.-) and .OH. The calculated rate constant for the O2(.-)-scavenging reaction was 5.03 +/- 0.03 x 10(7) M (-1) s (-1). However, the analysis of the Fenton and UV/H 2O 2 system in the presence of Pt nps suggested that the .OH-scavenging reaction cannot be determined in both systems. Among particle sizes tested from 1 to 5 nm, 1 nm Pt nps showed the highest O2(.-)-scavenging ability. Almost no cytotoxicity was observed even after adherent cells (TIG-1, HeLa, HepG2, WI-38, and MRC-5) were exposed to Pt nps at concentrations as high as 50 mg/L. Pt nps scavenged intrinsically generated reactive oxygen species (ROS) in HeLa cells. Additionally, Pt nps significantly reduced the levels of intracellular O2(.-) generated by UVA irradiation and subsequently protected HeLa cells from ROS damage-induced cell death. These findings suggest that Pt nps may be a new type of antioxidant capable of circumventing the paradoxical effects of conventional antioxidants.