分子印迹荧光传感构建及应用

构建一个高灵敏、高选择性检测痕量分析物的传感器广受科研工作者关注。分子印迹技术由于具有高选择性识别、高容量吸附、快速结合、热稳定性以及低成本等优点,已广泛应用于传感构建领域。以分子印迹聚合物为识别单元,结合荧光传感技术所构建的分子印迹荧光传感器在环境污染物痕量检测方面成为研究重点。本文主要介绍分子印迹聚合物的制备方法,总结分子印迹荧光传感器的构建机理和分子印迹荧光传感器在金属离子、有机小分子以及生物大分子检测方面的应用。重点探讨分子印迹传感器在不同数量的荧光团下检测一种或多种目标分析物的方法,包括单一荧光团检测单一目标物、比率荧光检测单一目标物以及分子印迹荧光传感的多元检测。基于以上分析和总结,提出分子印迹荧光传感器的当前挑战和发展前景。     

基于金属纳米簇的荧光传感平台的最新研究进展

荧光纳米生物传感平台由于具有灵敏度高、选择性好、操作简单、成本低、实时监测等特点,吸引了广泛的关注。近年来,随着纳米技术的飞速发展,具有纳米结构的材料(纳米材料)在生物传感领域显示出独特的优势。与传统材料相比,纳米材料显示出独特的物化性质,如光学、电学、机械、催化和磁性等。金属(如Au、Ag、Cu及其合金)纳米簇(MNCs)是纳米科学和纳米技术领域中一种新颖的多功能纳米材料,其通常由几个到几十个金属原子组成,其核的尺寸通常小于2 nm。由于其发光能力强、易于合成和进行表面功能化、生物相容性好、尺寸超小、毒性低等优点,金属纳米簇在能源催化、医学诊断、电子器件、生物传感等领域得到了广泛的应用。此外,金属纳米簇的荧光性能极佳(如大的斯托克斯位移、可调节的荧光、高的光学稳定性和荧光量子产率等),因此被作为荧光纳米探针广泛应用于生物传感领域。该综述介绍了近年来基于不同构建机制的金属纳米簇基的传感平台的研究进展,及其在检测离子、生物分子、pH和温度传感等方面的应用。相信该综述能为从不同传感机理构建更具前景的生物传感器提供一些新见解和理论指导。     

Tb3+参比碳点比率荧光传感器检测多菌灵

利用镧系元素-铽(Tb~(3+))参比CDs,开发具有双发射特性的Tb~(3+)参比碳点(PAN-CDsDPA-Tb)比率荧光传感器,用于检测食品基质中的多菌灵(MBC)。传感器通过π-π堆积实现PAN-CDsDPA-Tb识别MBC,并诱导基于内滤效应(IFE)和电子转移(ET)的同步荧光猝灭来实现MBC的比率荧光检测。该传感器的荧光比率在MBC浓度为0～0.091 mmol/L范围内呈线性响应,检测限为3.0 nmol/L。比率传感器的荧光同步响应增强了对MBC的特异性。该传感器在实际应用中具有良好的准确度和精密度,回收率为93.2%～105.1%,相对标准偏差(RSDs)为0.14%～2.4%,是一种高灵敏度的比率荧光纳米传感器,可用于复杂基质中农药残留的检测。     

环境友好型比率荧光微流控纸芯片快速检测苯醚甲环唑

本文构建了一种新型比率荧光印迹微流控纸芯片,将绿色荧光(NBD-APTES)作为对照荧光源,以半胱氨酸修饰后的碳量子点(CDs-Cys)的荧光变化来实现苯醚甲环唑的快速可视化检测.采用扫描电子显微镜和激光共聚焦显微镜等详细研究纸基芯片的检测性能.在优化条件下,该荧光传感器的线性范围为0.3~60μmol/L,检测限为75 nmol/L,样品回收率为102.1%~111.2%,准确度在3.1%~4.2%.与传统液相荧光传感材料相比,固相基质的比率荧光传感器具备更好的携带性和储存性,表现出令人满意的荧光检测特性.此外,该传感器用于分离和检测苯醚甲环唑时具有高度的特异性,已成功地应用于实际样品的检测,为新型比率荧光技术与微流控纸基芯片结合开辟了新途径,并为未来提供了潜在的即时医疗应用前景.     

量子点比率荧光探针研究进展

量子点(QDs)是一种纳米发光粒子,具有优异的发光性能,在太阳能利用、荧光检测等方面具有广阔的应用前景。QDs与另一荧光团复合可构建比率荧光探针,实现可视化检测目标物并且提高了检测灵敏度。本文主要对QDs比率荧光探针的种类、构建方法和应用领域的研究进展进行综述,并对其中的不足进行分析,以期为研发具有优异性能的比率荧光探针提供借鉴。     

量子点荧光传感器的设计及应用

量子点(quantum dots,QDs)是一种新型的纳米荧光材料,具有优良的光电性质,已广泛应用于荧光传感及可视化检测,可实现对靶标分子高灵敏、高特异性分析。本文主要论述了量子点的表面化学修饰,以及量子点传感的作用原理,如荧光共振能量转移、电荷转移、直接荧光传感、生物发光共振能量转移、化学发光共振能量转移以及电化学发光,利用这些原理设计出不同的荧光传感器,并应用于不同分子或离子的可视化检测。同时对量子点的荧光传感存在的问题及挑战进行了总结,并提出量子点荧光传感将向生物相容性好、细胞或生物体内实时可视化检测、复杂体系中进行多靶标同时检测以及量子点的逻辑运算等方向发展。     

荧光可视化技术在食品分析中的应用进展

介绍了常见的荧光可视化传感器(比率、纸基、分子印迹荧光传感器),荧光可视化传感机制(荧光共振能量转移、内滤效应、光诱导电子转移、聚集诱导猝灭、聚集性诱导发射、分子内电荷转移、金属-配体电荷转移等)及其判定方法，综述了量子点(普通量子点和生物质量子点)、有机荧光物质和金属荧光纳米团簇等发光物质作为荧光可视化探针在食品分析中的应用，并对其发展前景进行了展望(引用文献69篇)。     

新型分子印迹荧光传感器的构建与应用

分子印迹聚合物因具有构效预定性、特异识别性和广泛实用性,将其作为传感器识别单元的研究已成为当前的研究热点.分子印迹荧光传感器结合了分子印迹的高选择性与荧光检测的高灵敏度,非常适合复杂样品中痕量目标物的分析测定,在分离检测等领域备受关注.根据荧光材料的不同,本文详细介绍了以量子点、有机荧光染料、化学发光反应物质以及其他材料为荧光信号单元的新型分子印迹荧光传感器的构建与应用,总结了不同荧光传感器的构建方法、检测机理,探讨了基于比率型荧光的分子印迹传感器的制备与发展,并对分子印迹荧光传感器的发展前景进行了展望.     

基于银纳米粒子构建荧光传感平台用于核酸检测

报道了基于银纳米粒子构建的荧光传感平台,并用于核酸检测.此荧光传感平台对核酸检测基于以下策略:首先,荧光团标记的单链DNA探针被吸附到银纳米粒子的表面,荧光团与银纳米粒子近距离接触,发生荧光猝灭;加入与探针DNA序列互补的目标DNA,两者杂交形成双链DNA,并从银纳米粒子的表面脱离,荧光得到恢复.这种银纳米粒子构建的荧...     

荧光化学传感器的研究进展

从荧光指示剂的设计原理、固定方法及传感器材料三方面,对荧光化学传感器近年来的进展作了评述,特别是对一些新型荧光化学传感器的应用及纳米传感新材料的发展作了重点介绍。此外,对荧光化学传感器的发展前景作了展望。     

Ratiometric fluorescence detection of bleomycin based on proximity-dependent fluorescence conversion of DNA-templated silver nanoclusters

We design a ratiometric fluo rescent sensing platform for bleomycin(BLM) by using proximity-dependent DNA-templated silver nanoclusters(DNA-AgNCs) probe.This ratiometric sensing system is constructed with DNA-AgNCs as single fluorophore.The proposed strategy is based on the two following facts:(1) a covert DNA can approach and transform the DNA-AgNCs with green emission(G-DNA-AgNCs) into red emission through hybridization reaction.(2) The specific cleavage of the convert DNA by BLM in the presence of Fe(Ⅱ) inhibits the discoloration of G-DNA-AgNCs.Thus,benefiting from the specific recognition of BLM and unique properties of G-DNA-AgNCs,a hignly-sensitive ratiometric sensor for BLM has been successfully developed.The detection limit is as low as 30 pmol/L.This label-free fluorescence probe possesses advantages of convenient synthetic process and low cost.Moreover,this ratiometric method has been applied to the detection of BLM in human serum samples,illustrating a promising tool for analysis of BLM in cancer therapy.     

A FRET-based ratiometric sensor for mercury ions in water with multi-layered silica nanoparticles as the scaffold

A FRET system was built for ratiometric sensing of Hg(2+) in water with multilayered silica nanoparticles as the scaffold. This architecture ensures the control over the location of both donor and acceptor and their separation distance within nanoparticles, affording higher energy transfer efficiency and higher signal-to-background ratio for particle-based sensing.     

Ultrasensitive Silicon Nanoparticle Ratiometric Fluorescence Determination of Mercury(II)

A novel ratiometric fluorescence sensing system for the ultrasensitive detection of Hg²⁺ was developed. It used aminofunctionalized silicon nanoparticles and rhodamine B, which exhibit two distinct fluorescence emission peaks at 449 and 581?nm, respectively, under a single excitation wavelength (350?nm). The fluorescence of the amino-functionalized silicon nanoparticles was selectively quenched by Hg²⁺, while that of rhodamine B was insensitive to Hg²⁺. The ratio of fluorescence intensities at 449–581?nm linearly decreased with increasing concentrations of Hg²⁺ from 0.005–0.1 and 0.1–7?µM within 0.5?min, and a detection limit as low as 3.3?nM was achieved. Moreover, the ratiometric fluorescence sensing system exhibited good selectivity toward Hg²⁺ over other metal ions with relatively low background interference, even in a complex matrix such as lake water. Most importantly, the practical use of this sensing system for Hg²⁺ detection in real water samples was also demonstrated.     

Activatable nanoscale metal-organic framework for ratiometric photoacoustic imaging of hydrogen sulfide and orthotopic colorectal cancer in vivo

Nanoscale metal-organic frameworks(nano MOFs) have emerged as a promising biomedical nanoplatform because of their unique properties. However, the exploration of nano MOFs in photoacoustic(PA) imaging is still limited. Here, a novel hydrogen sulfide(H2 S)-activated nano copper-based MOF(Cu-MOF) was developed as a near-infrared(NIR) ratiometric PA probe for in vivo monitoring of endogenous H2 S level and orthotopic colorectal cancer imaging via in situ reaction of nano Cu-MOFs with endogenous H_2 S that is closely associated with tumor growth and proliferation in colon cancer. The synthesized nano Cu-MOFs displayed excellent PA responsiveness towards tumor H_2 S level with high selectivity and rapid kinetics. The result suggests the developed probe may provide a unique opportunity to investigate the malignant behaviors of H_2 S-associated events in vivo.     

A new ratiometric and colorimetric chemosensor for cyanide anion based on coumarin-hemicyanine hybrid

A hybrid coumarin-hemicyanine dye, Cou-BT, was developed as a new ratiometric and colorimetric sensor for cyanide with a sensing mechanism via nucleophilic addition of cyanide anion to the benzothiolium group. Cou-BT shows high sensitivity and selectivity for cyanide detection over other common anion species in aqueous acetonitrile solution. The calculated pseudo-first-order rate constant for cyanide anion addition was (2.13 ± 0.08) × 10(-2) s(-1) at 298 K, and the detection limit was estimated to be 0.64 μM. The DFT and TDDFT calculation results suggest that the ratiometric and colorimetric sensing behavior of Cou-BT upon its reaction with cyanide was due to the interrupted π-conjugation and blocked ICT progress.     

A Zn2+-specific turn-on fluorescent probe for ratiometric sensing of pyrophosphate in both water and blood serum

A novel fluorescent sensor composed of a naphthalene functionalized tetraazamacrocycle ligand 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3-methyl naphthalene (1) and Zn(2+) has been designed and prepared, which can be utilized for selective and ratiometric sensing of pyrophosphate (PPi) over other phosphate-containing anions in aqueous solution at physiological pH. Notably, the water soluble 1 itself also exhibits a selective enhanced fluorescent response to Zn(2+), and the complex 1-Zn(2+) thus formed eventually fulfils the synergic Zn(2+) coordination-altered strategy with PPi. Furthermore, the ratiometric sensing of 1-Zn(2+) towards PPi performed well even in blood serum milieu. Finally, the sensor 1-Zn(2+) was successfully employed to monitor a real-time assay of inorganic pyrophosphatase (PPase) by means of ratiometric fluorescent measurements for the first time.     

A nanoparticle-supported fluorescence resonance energy transfer system formed via layer-by-layer approach as a ratiometric sensor for mercury ions in water

This article describes the design and preparation of a novel fluorescence resonance energy transfer (FRET)-based ratiometric sensor with the polymer nanoparticle as scaffold for detecting Hg²⁺ in aqueous media. In this study, a fluorescent dye fluorescein isothiocyanate (FITC, served as the donor) and a spirolactam rhodamine derivative (SRHB, served as mercury ion probe) were covalently attached onto polyethylenimine (PEI) and polyacrylic acid (PAA) respectively; and a ratiometric sensing system was then formed through the deposition of the donor- and probe-containing polyelectrolytes onto the negatively charged polymer particles via the layer-by-layer approach. The ratiometric fluorescent signal change of the system is based on the intra-particle fluorescence resonance energy transfer (FRET) process modulated by mercury ions. Under optimized structural and experimental conditions, the particle-based detection system exhibits stable response for Hg²⁺ in aqueous media. More importantly, in this newly developed particle-based detection system formed by LBL approach, varied numbers of the PAA/PEI layers which served as the spacer could be placed between the donor-containing layer and the probe-containing layer, hence the donor–acceptor distance and energy transfer efficiency could be effectively tuned (from ca. 25% to 76%), this approach has well solved the problem for many particle-based FRET systems that the donor–acceptor distance cannot be precisely controlled. Also, it is found that the ratiometric sensor is applicable in a pH range of 4.6–7.3 in water with the detection limit of 200 nM. This approach may provide a new strategy for ratiometric detection of analytes in some environmental and biological applications.     

5-氨基-1,10-菲咯啉：可异构化杂环螯合荧光载体作为比例计量型锌离子荧光探针的一种原型

5-amino-l,10-phenanthroline （5-AP）, as a tautomeric heterocyclic aromatic chelating fluorophore （THACF）, can sense Zn^2＋ selectively by shifting emission from 495 to 564 nm upon Zn^2＋ addition in ethanol. The ratiometric fluorescent sensing behavior has been correlated to the tautomerization of 5-AP affected by solvents and metal chelation. The strategy using THACF as ratiometric fluorescent sensor for Zn^2＋ not only simplifies the synthetic procedure but also gives a promising alternative for Zn^2＋ ratiometric fluorescent sensor design.     

Water‐soluble AIE‐Active Fluorescent Organic Nanoparticles: Design,Preparation and Application for Specific Detection of Cysteine over Homocysteine and Glutathione in Living Cells

Water‐soluble ratiometric AIE‐active fluorescent organic nanoparticles 2OA‐FON for the specific sensing of cysteine over other biothiols are reported. The obtained amphiphilic probe included olefin aldehyde as recognizing unit, tetraphenylethylene as fluorescence reporter and lactose moiety as a hydrophilic group. This work provides a general design strategy based on the introduction of a sugar moiety into a hydrophobic AIEgen to develop ratiometric water‐soluble fluorescent organic nanoparticles.     

Ratiometric sensing of mercury(II) based on a FRET process on silica core-shell nanoparticles acting as vehicles

We report on a fluorescence resonance energy transfer (FRET)-based ratiometric sensor for the detection of Hg(II) ion. First, silica nanoparticles were labeled with a hydrophobic fluorescent nitrobenzoxadiazolyl dye which acts as a FRET donor. A spirolactam rhodamine was then covalently linked to the surface of the silica particles. Exposure of the nanoparticles to Hg(II) in water induced a ring-opening reaction of the spirolactam rhodamine moieties, leading to the formation of a fluorescent derivative that can serve as the FRET acceptor. Ratiometric sensing of Hg(II) was accomplished by ratioing the fluorescence intensities at 520 nm and 578 nm. The average decay time for the donor decreases from 9.09 ns to 7.37 ns upon addition of Hg(II), which proves the occurrence of a FRET process. The detection limit of the assay is 100 nM (ca. 20 ppb). The sensor also exhibits a large Stokes shift (>150 nm) which can eliminate backscattering effects of excitation light.