基于Mn掺杂ZnS量子点室温磷光法测定水样中百草枯

利用水相合成法制备了3-巯基丙酸(3-Mercaptopropionic Acid,MPA)包裹的Mn掺杂ZnS量子点(Quantum Dots,QDs),基于该量子点的室温磷光性质,构建了一种快速、灵敏检测水样中百草枯(Paraquat,PQ)含量的新方法。方法无需添加任何除氧剂和诱导剂等复杂的预处理过程。在pH=7.4的磷酸盐缓冲溶液中,PQ通过静电作用可以猝灭Mn掺杂ZnS QDs在波长590nm处的磷光,且在一定范围内PQ的浓度与磷光猝灭强度(P0/P)呈良好的线性关系,线性范围为2.5~50μg/L,相关系数为0.994,方法检出限为0.769μg/L。该方法适用于不同水样中百草枯的痕量检测。     

量子点室温磷光探针检测生物体液中的头孢哌酮钠舒巴坦钠

以水相合成的3-巯基丙酸包覆的Mn掺杂Zn S量子点(MPA-Mn/Zn S QDs)作为室温磷光探针,基于头孢哌酮钠舒巴坦钠(CPZ-SBT)作为一种电子受体,可通过电子转移有效猝灭Mn/Zn S QDs的室温磷光效应,构建了一种测定痕量CPZ-SBT的方法.当CPZ-SBT浓度为0.7~84μg/L时,其与MPA-Mn/Zn S QDs的磷光强度之间呈良好线性关系,相关系数为0.99,该方法的检出限为0.14μg/L.     

基于Mn掺杂ZnS量子点的室温磷光猝灭法测定H2O2

以N-乙酰基-L-半胱氨酸为稳定剂,合成了具有独特光学性质的水溶性Mn掺杂ZnS量子点(QDs)。该量子点在室温不除氧的条件下即可发射较强的磷光信号,最大发射波长位于592nm处。在pH=7.0的磷酸盐缓冲溶液中,H2O2对量子点有显著的磷光猝灭作用,且在一定的范围内H2O2的浓度与磷光猝灭值(P0/P)呈现良好的线性关系,以此建立了测定H2O2的新方法。在最佳的实验条件下,该方法的检出限为1.0×10-6 mol/L,线性范围为1.0×10-5～2.5×10-2 mol/L,相关系数为0.9978。通过测定猝灭过程的时间分辨磷光光谱,推断猝灭机理为动态猝灭。     

量子点室温磷光法检测生物体液中尿酸

在水相中合成了3-巯基丙酸包覆的Mn掺杂ZnS量子点,基于Mn掺杂ZnS量子点的室温磷光特性,利用尿酸中的强吸电子基羰基通过电子转移能够有效猝灭量子点磷光,构建了一种检测尿酸的方法,该法无需预处理过程。结果表明,在pH 7.4的磷酸盐缓冲溶液中,尿酸对Mn掺杂ZnS量子点的猝灭程度呈线性变化,线性范围为2~70μmol/L,相关系数为0.99,检出限为0.31μmol/L。用于尿样中加标回收,加标回收率为97.5%~100.3%。方法适用于人体液中痕量尿酸的检测。     

基于室温磷光量子点/硼酸基联吡啶盐纳米复合材料检测果糖

以Mn掺杂的ZnS(Mn-ZnS)室温磷光(RTP)量子点的磷光为信号,以2-溴甲基苯硼酸与4,4ˊ-联吡啶为原料合成的硼酸基联吡啶盐(BBV)为受体,带负电的量子点与带正电BBV通过静电作用形成Mn-ZnS/BBV纳米复合材料,Mn-ZnS量子点磷光猝灭,加入果糖,BBV与果糖形成阴离子硼酸酯,降低了对量子点猝灭效率,RTP恢复.考察了时间、pH值对Mn掺杂的ZnS QDs/BBV纳米复合材料磷光强度的影响,在最优条件下,此传感器检测果糖的线性范围为0.05~1.00 mmol/L,检出限为0.01 mmol/L,相关系数r为0.99.本磷光分析法简便快速、灵敏度高,有望应用于食品、医药行业中果糖含量的检测分析.     

基于Mn掺杂ZnS量子点的室温磷光检测盐酸异丙嗪

以三巯基丙酸(MPA)为表面修饰剂,采用水相合成法制备了稳定且具有良好光学性质的Mn掺杂Zn S量子点。在p H 7.4的磷酸缓冲液中,盐酸异丙嗪的加入使MPA包裹的Mn掺杂Zn S量子点的室温磷光发生明显猝灭,据此建立了一种检测盐酸异丙嗪的新方法。磷光猝灭强度(ΔRTP)与盐酸异丙嗪浓度呈良好线性,其线性范围为3.2~32μmol/L与32~160μmol/L,相关系数分别为0.998与0.999,检出限为0.553μmol/L。将该方法用于人血清与尿液中盐酸异丙嗪的检测,加标回收率为96.4%~103.1%,结果满意。     

硫鸟嘌呤修饰的Mn:ZnS QDs磷光探针检测铂(Ⅲ)

通过水相合成法制备了硫鸟嘌呤(TG)修饰的锰掺杂硫化锌量子点(TG-Mn:ZnS QDs)。加入Pt⁴⁺后,Pt⁴⁺会与硫鸟嘌呤上的氮原子结合形成N-Pt⁴⁺配位结构附着在TG-Mn:ZnS QDs的表面,随着Pt⁴⁺浓度的增加,TG-Mn:ZnS QDs-Pt⁴⁺体系发生电子转移而导致磷光逐渐被猝灭,基于此构建了检测Pt⁴⁺的磷光探针。实验中考察了p H、时间对Pt⁴⁺猝灭TG-Mn:ZnS QDs磷光强度的影响。在最佳实验条件下,Pt⁴⁺浓度在0.06~2.4μg/mL范围内与TG-Mn:ZnS QDs的磷光强度呈良好的线性关系y=0.0884x+0.2319,R²=0.991,方法检出限(3σ/n)为1.3μg/mL。该磷光探针适用于实际样品中Pt⁴⁺含量的测定。     

胸腺嘧啶修饰的Mn:ZnS量子点作为室温磷光传感器用于Hg~(2+)的检测

采用胸腺嘧啶修饰的Mn:ZnS量子点作为室温磷光传感器检测Hg~(2+)。量子点溶液在加入Hg~(2+)后,磷光强度迅速下降并在15 min内达到稳定。Hg~(2+)对量子点的磷光猝灭方式是动态猝灭与静态猝灭相结合,Hg~(2+)与量子点在激发态相互作用导致量子点动态猝灭,并且在静态猝灭过程中,Hg~(2+)和胸腺嘧啶在基态相互作用形成T-Hg~(2+)-T的发夹结构产生了不发光的络合物。在最优反应条件下,量子点的磷光强度随Hg~(2+)的浓度在2～18μmol/L范围内呈良好的线性关系(R~2=0.9992)。     

基于Mn掺杂ZnS量子点室温磷光法检测环丙沙星

建立了基于3-巯基丙酸包裹的Mn掺杂Zn S量子点室温磷光性质定量检测环丙沙星的方法。方法不需要脱氧剂和诱导剂,并且能够有效的避免生物体液的自体荧光和散色光的干扰。在最优化实验条件下,随着环丙沙星浓度的增大,Mn掺杂Zn S量子点室温磷光强度在590 nm处呈现出非常有规律的猝灭,其线性范围为1.2~60μmol/L,检出限(3σ)为0.3μmol/L。在人体血液中的加标回收率为93%~106%。     

基于Mn掺杂ZnS量子点室温磷光法测定生物体液中的磺胺嘧啶钠

利用水相合成法合成了MPA(3-巯基丙酸)包覆的Mn掺杂Zn S量子点,基于该掺杂型量子点的室温磷光性质,建立了一种检测磺胺嘧啶钠(SDS)的新方法。该方法可以有效避免生物体液的自体荧光和散射光,且在水溶液检测时不需要添加任何诱导剂和除氧剂。在p H 7.4磷酸盐缓冲介质中,通过静电作用,SDS可以猝灭Mn掺杂Zn S量子点在590 nm处的磷光,其猝灭的磷光强度与SDS浓度呈良好的线性关系。其线性范围4~400μmol/L,相关系数R=0.99,检出限为0.78μmol/L,相对标准偏差(RSD)为2.6%。     

ZnS:Mn/ZnS量子点在DNA定量分析中的应用

以巯基乙酸为稳定剂,采用成核掺杂的方法在水溶液中一步制备得到具有核壳结构的ZnS:Mn/ZnS量子点.研究了荧光、室温磷光产生的机理.基于DNA对量子点发光的增强效应,以ZnS:Mn/ZnS量子点作为标记探针建立了测定DNA的荧光、室温磷光的分析方法.考察了量子点浓度、EDC/NHS用量和反应时间等条件对DNA测定的影...     

Protein‐Directed Synthesis of Mn‐Doped ZnS Quantum Dots: A Dual‐Channel Biosensor for Two Proteins

Proteins typically have nanoscale dimensions and multiple binding sites with inorganic ions, which facilitates the templated synthesis of nanoparticles to yield nanoparticle–protein hybrids with tailored functionality, water solubility, and tunable frameworks with well‐defined structure. In this work, we report a protein‐templated synthesis of Mn‐doped ZnS quantum dots (QDs) by exploring bovine serum albumin (BSA) as the template. The obtained Mn‐doped ZnS QDs give phosphorescence emission centered at 590 nm, with a decay time of about 1.9 ms. A dual‐channel sensing system for two different proteins was developed through integration of the optical responses (phosphorescence emission and resonant light scattering (RLS)) of Mn‐doped ZnS QDs and recognition of them by surface BSA phosphorescent sensing of trypsin and RLS sensing of lysozyme. Trypsin can digest BSA and remove BSA from the surface of Mn‐doped ZnS QDs, thus quenching the phosphorescence of QDs, whereas lysozyme can assemble with BSA to lead to aggregation of QDs and enhanced RLS intensity. The detection limits for trypsin and lysozyme were 40 and 3 nM , respectively. The selectivity of the respective channel for trypsin and lysozyme was evaluated with a series of other proteins. Unlike other protein sensors based on nanobioconjugates, the proposed dual‐channel sensor employs only one type of QDs but can detect two different proteins. Further, we found the RLS of QDs can also be useful for studying the BSA–lysozyme binding stoichiometry, which has not been reported in the literature. These successful biosensor applications clearly demonstrate that BSA not only serves as a template for growth of Mn‐doped ZnS QDs, but also impacts the QDs for selective recognition of analyte proteins.     

基于Mn掺杂ZnS量子点的室温磷光传感应用的研究进展

与一般有机染料分子相比,半导体材料量子点具有优异的光学性能,在多个领域得到了广泛的应用.量子点具有窄而对称且可调的发射波长、宽激发强吸收、抗光漂白能力强以及水溶性好等诸多优势,引起了研究者广泛关注.为了增加量子点的斯托克斯位移从而很好地避免量子点的自猝灭现象,引入掺杂物是一种很有效的方式.掺杂量子点不仅保留了量子点原有的优点,而且还赋予量子点额外的优异性能.如Mn掺杂ZnS量子点生物相容性好,不含Cd和Hg等有害元素,而且Mn2+的加入使其具有优异的室温磷光特性.磷光检测能很好地避开生物背景荧光的干扰,使得Mn掺杂ZnS量子点能够广泛应用于磷光生物分析.本文综述了Mn掺杂ZnS量子点在室温磷光分析中的研究进展,着重介绍了几种具有启发意义的设计策略,包括其发光机理以及应用于离子、分子以及生物大分子等的检测.     

Synthesis of Multifunctional Mn‐Doped CdTe/ZnS Core/Shell Quantum Dots

The synthesis of a novel water‐soluble Mn‐doped CdTe/ZnS core‐shell quantum dots using a proposed ultrasonic assistant method and 3‐mercaptopropionic acid (MPA) as stabilizer is descried. To obtain a high luminescent intensity, post‐preparative treatments, including the pH value, reaction temperature, reflux time and atmosphere, have been investigated. For an excellent fluorescence of Mn‐doped CdTe/ZnS, the optimal conditions were pH 11, reflux temperature 100°C and reflux time 3 h under N₂ atmosphere. While for phosphorescent Mn‐doped CdTe/ZnS QDs, the synthesis at pH 11, reflux temperature 100°C and reflux time 3 h under air atmosphere gave the best strong phosphorescence. The characterizations of Mn‐doped CdTe/ZnS QDs were also identified using AFM, IR, powder XRD and thermogravimetric analysis. The data indicated that the photochemical stability and the photoluminescence of CdTe QDs are greatly enhanced by the outer inorganic ZnS shell, and the doping Mn²⁺ ions in the as‐prepared quantum dots contribute to strong luminescence. The strong luminescence of Mn‐doped CdTe/ZnS QDs reflected that Mn ions act as recombination centers for the excited electron‐hole pairs, attributing to the transition from the triplet state (⁴T₁) to the ground state (⁶A₁) of the Mn²⁺ ions. All the experiments demonstrated that the surface states played important roles in the optical properties of Mn‐doped CdTe/ZnS core‐shell quantum dots.     

Aptamer‐Based Turn‐On Detection of Thrombin in Biological Fluids Based on Efficient Phosphorescence Energy Transfer from Mn‐Doped ZnS Quantum Dots to Carbon Nanodots

This paper presents the first example of a sensitive, selective, and stable phosphorescent sensor based on phosphorescence energy transfer (PET) for thrombin that functions through thrombin–aptamer recognition events. In this work, an efficient PET donor–acceptor pair using Mn‐doped ZnS quantum dots labeled with thrombin‐binding aptamers (TBA QDs) as donors, and carbon nanodots (CNDs) as acceptors has been constructed. Due to the π–π stacking interaction between aptamer and CNDs, the energy donor and acceptor are taken into close proximity, leading to the phosphorescence quenching of donors, TBA QDs. A maximum phosphorescence quenching efficiency as high as 95.9 % is acquired. With the introduction of thrombin to the “off state” of the TBA‐QDs‐CNDs system, the phosphorescence is “turned on” due to the formation of quadruplex‐thrombin complexes, which releases the energy acceptor CNDs from the energy donors. Based on the restored phosphorescence, an aptamer‐based turn‐on thrombin biosensor has been demonstrated by using the phosphorescence as a signal transduction method. The sensor displays a linear range of 0–40 nM for thrombin, with a detection limit as low as 0.013 nM in pure buffers. The proposed aptasensor has also been used to monitor thrombin in complex biological fluids, including serum and plasma, with satisfactory recovery ranging from 96.8 to 104.3 %. This is the first time that Mn‐doped ZnS quantum dots and CNDs have been employed as a donor–acceptor pair to construct PET‐based biosensors, which combines both the photophysical merits of phosphorescence QDs and the superquenching ability of CNDs and thus affords excellent analytical performance. We believe this proposed method could pave the way to a new design of biosensors using PET systems.     

Ascorbic Acid Induced Enhancement of Room Temperature Phosphorescence of Sodium Tripolyphosphate‐Capped Mn‐Doped ZnS Quantum Dots: Mechanism and Bioprobe Applications

Although quantum dot (QD)‐based room temperature phosphorescence (RTP) probes are promising for practical applications in complex matrixes such as environmental, food and biological samples, current QD‐based‐RTP probes are not only quite limited but also exclusively based on the RTP quenching mechanism. Here we report an ascorbic acid (AA) induced phosphorescence enhancement of sodium tripolyphosphate‐capped Mn‐doped ZnS QDs, and its application for turn‐on RTP detection. The chelating ability allows AA to extract the Mn and Zn from the surface of the QDs and to generate more holes which are subsequently trapped by Mn²⁺, while the reducing property permits AA to reduce Mn³⁺ to Mn²⁺ in the excited state, thereby enhancing the excitation and orange emission of the QDs. The enhanced RTP intensity of the QDs increases linearly with the concentration of AA in the range of 0.05–0.8 μM . Thus, a QD‐based RTP probe for AA is developed. The proposed QD‐based turn‐on RTP probe avoids tedious sample pretreatment, and offers good sensitivity and selectivity for AA in the presence of the main relevant metal ions and other molecules in biological fluids. The limit of detection (3s) of the developed method is 9 nM AA, and the relative standard deviation is 4.8 % for 11 replicate detections of 0.1 μM AA. The developed method is successfully applied to the analysis of real samples of human urine and plasma for AA with quantitative recoveries from 96 to 105 %.     

基于L-半胱氨酸修饰的锰掺杂ZnS量子点应用于叶酸测定

以L-半胱氨酸为表面修饰剂制备了稳定性和水溶性均优的ZnS∶Mn2+纳米晶,并应用于叶酸的检测。在pH 7.4的KH2PO4-Na2HPO4 缓冲溶液中,叶酸的加入使ZnS∶Mn2+体系的荧光发生猝灭,荧光强度的变化与叶酸浓度呈良好的线性关系,其线性范围为1.0×10-6~7.0×10-5 mol?L-1 （4.4×10-4~3.1×10-2 g?L-1）,方法检出限为9.6×10-7 mol?L-1 （4.2×10-4 g?L-1）。该方法用于叶酸片剂和健康人尿液中叶酸的测定,结果满意。采用荧光光谱、紫外可见吸收光谱及X-ray光谱等研究了ZnS∶Mn2+纳米晶及其水溶液的特性,通过热力学参数对叶酸测定的可能机理进行了探讨。     

DNA detection based on Mn-doped ZnS quantum dots/methylene blue nanohybrids

Nanohybrids were formed from 3-mercaptopropionic acid(MPA)-coated Mn-doped ZnS quantum dots(QDs) and methylene blue(MB) via electrostatic interaction, and then used in the detection of trace DNA.The principle of detection is as follows: MB binds with Mn-doped ZnS QDs via electrostatic interaction,and then quenches the room temperature phosphorescence(RTP) of the QDs through photoinduced electron-transfer(PIET). After the addition of DNA, MB binds with DNA through intercalation and electrostatic interaction, and desorbs from the surfaces of Mn-doped ZnS QDs, which recovers the RTP of the QDs. On this basis, a DNA detection method based on the properties of RTP was set up. This method shows a detection range of 0.2–20 mg/L, and a detection limit of 0.113 mg/L. Since this method is based on the RTP of QDs, it is not interfered by the background fluorescence or scattering light in vivo, and thus,avoids complex sample pretreatment. Thus, this method is very feasible for detection of trace DNA in biofluids.