核壳结构上转换发光纳米粒子的合成及用于细胞色素C的检测

本工作合成了三层核壳结构的上转换发光纳米粒子,其中第一层是惰性核,第二层为发光层,为了增强上转换发光强度,又在表面包覆了第三层惰性壳层。该材料粒径均一、分散性良好,其发光层厚度约为2.4nm,惰性壳层厚度约为2.9nm。在其表面修饰了细胞色素C的适配体链及互补链,在适配体的3’端修饰了BHQ3基团,能够猝灭上转换纳米粒子在655nm波长处的发光。当细胞色素C存在时,适配体与细胞色素C结合从而离开其表面,使655nm处的发光恢复。在检测过程中,540nm处的发光强度不会发生变化,可以用作细胞色素C的比率荧光检测。结果表明,当细胞色素C浓度在5~80μmol/L范围时,发光信号恢复程度与细胞色素C浓度呈线性相关,相关系数为0.998,检出限为1μmol/L。所建立方法可为细胞色素C的荧光检测提供一种新的技术思路。

NaYF4:Yb/Er稀土上转换发光纳米粒子的可控合成

与传统的有机染料或者其它荧光纳米材料相比,稀土上转换材料具有稳定性好、毒性低、量子效率高、背景荧光干扰小、信噪比高等优点。开发出荧光效率高、粒径可控、生物相容性好的稀土上转换纳米材料引起了众多科研工作者的兴趣。

上转换发光纳米粒子表面修饰及应用研究进展

由于上转换发光纳米技术能够快速、准确、高效的检测食品中的危害因素,因此成为了食品安全检测技术研究的热点。上转换发光纳米粒子的合成与表面修饰是上转换发光纳米技术在食品安全检测中运用的关键。因此介绍上转换发光纳米粒子的合成方法和表面修饰,以及在食品安全检测中上转换发光纳米材料表面修饰的应用情况。

5-氨基间苯二甲酸敏化LaF_3∶Tb发光纳米粒子的合成及其细胞成像

以稀土硝酸盐、NH4F、5-氨基间苯二甲酸(AIPA)和柠檬酸为反应原料,水热法一锅合成了水溶性良好的AIPA敏化LaF3∶Tb(AIPA-LaF3∶Tb)纳米粒子。采用X射线衍射、透射电镜、红外光谱等对粒子进行了表征。结果表明,合成粒子为六方晶系的LaF3晶体,粒径为8 nm左右,粒子表面包覆了AIPA。测试了合成粒子的发光性能,其最大激发和发射波长分别为348和547 nm,粒子中存在着AIPA向Tb3+的能量传递。和LaF3∶Ce,Tb粒子相比,AIPA-LaF3∶Tb粒子的激发波长红移了94 nm,发光强度增大。在合成的基础上,对AIPA-LaF3∶Tb粒子进行了氨基化修饰,然后将氨基化粒子和兔抗人CEA抗体偶联,最后用偶联了抗体的AIPA-LaF3∶Tb粒子对HeLa细胞进行免疫标记与成像。

MgGa_(2)O_(4)∶Cr^(3+),Al^(3+)近红外发光长余辉纳米粒子的制备及发光性能研究

利用乙二醇辅助共沉淀法,制备了小尺寸近红外发光Al^(3+)共掺杂镓酸镁(MgGa_(2)O_(4))∶0.3%Cr^(3+)(MGO∶0.3%Cr^(3+),Al^(3+))长余辉发光纳米粒子(PLNP),考察了Al^(3+)掺杂对MGO∶0.3%Cr^(3+)晶体结构和光学性质的影响。研究结果表明,Al^(3+)掺杂对MGO∶0.3%Cr^(3+)的晶体结构无影响,但能提高MGO∶0.3%Cr^(3+)的发光强度。当Al^(3+)掺杂量为0.4%(摩尔分数)时,MGO∶0.3%Cr^(3+),0.4%Al^(3+)(Al^(3+)、Cr^(3+)相对于Ga^(3+)的物质的量比,摩尔分数)PLNP发光强度最强,余辉平均发光寿命从46.98s(MGO∶0.3%Cr^(3+))增大至78.75s(MGO∶0.3%Cr^(3+),0.4%Al^(3+)),平均粒径为(6.53±1.79)nm。本研究为制备小尺寸和高发光强度的PLNP提供了一种有效的方法。此外,高发光强度和长余辉寿命的MGO∶0.3%Cr^(3+),0.4%Al^(3+) PLNP为光学传感、成像和治疗等提供了材料支撑。

稀土上转换发光纳米粒子NaYF_4:Yb^(3+),Er^(3+)与细胞相互作用机制的初步研究

选用两种典型的稀土上转换发光纳米粒子,即表面包覆氨基带正电的Na YF4:Yb3+,Er3+纳米粒子(HINPs)和包裹巯基带负电的Na YF4:Yb3+,Er3+纳米粒子(HMNPs),探究这两种粒子与细胞相互作用的机制。虽然HINPs和HMNPs的表面电性不同,但是理化性质相近、荧光发光强度相差不大,因此不会造成显著的成像差异。通过使用共聚焦成像和流式细胞仪进行检测,对比三种培养环境(正常培养条件、抑制膜蛋白活性培养条件和阻碍细胞内消耗能量运输过程的培养条件)的实验结果,发现HINPs和HMNPs的跨膜是一种消耗能量的受体介导的胞吞运输过程。另外,细胞对HINPs的摄取量要远大于对HMNPs的摄取量,说明带正电的粒子更容易和带负电的细胞膜相结合并进入细胞。

发光金纳米粒子测定曲通X-100及其临界胶束浓度

参照文献方法合成了BSA保护的水溶性发光金纳米粒子,并考察了此探针在非离子表面活性剂曲通X-100中的发光行为。根据观察到的发光增强效应,建立了一种简单的测定曲通X-100的方法。考察了发光金纳米粒子的浓度、体系酸度、反应时间及共存物质对测定的影响。在最佳条件下,发光强度与曲通X-100的浓度分别在0～150μmol/L和150～600μmol/L范围内分段成正比关系。两条工作曲线的交点所对应的浓度与曲通X-100的临界胶束浓度十分吻合,为胶束形成过程提供了直接的指示。作为一种生物相容性探针,发光金纳米粒子被用于生物学样品中曲通X-100的分析测定,结果令人满意。

基于发光金纳米粒子荧光增强法测定溶菌酶

参照文献方法合成了BSA修饰的水溶性发光金纳米粒子,并考察了其与溶菌酶之间的相互作用。依据溶菌酶对金纳米粒子的发光增强现象,建立了测定溶菌酶的荧光新方法。考察了发光金纳米粒子的浓度、pH值、反应时间及共存物质对测定的影响。优化条件为:发光金纳米粒子浓度4.0×10-6 mol/L、pH 7.0、反应时间10 min。在此条件下,荧光增强与溶菌酶浓度在2×10-7～8×10-6 mol/L范围内呈良好的线性关系,检出限为3.0×10-8 mol/L。对4.0×10-6 mol/L溶菌酶平行测定6次,相对标准偏差为2.6%。本方法具有灵敏度高、探针水溶性好和生物毒性低的优点,同时,常见低等电点蛋白质对分析不干扰。本方法用于合成样品及鸡蛋清中溶菌酶含量测定,平均回收率为97.5%～103.6%。

固定化金属离子亲和发光二氧化硅纳米粒子的制备及其用于磷酸化蛋白免疫印迹标记

发展了一种能够识别磷酸化蛋白的固定化金属离子亲和发光二氧化硅纳米粒子用于免疫印迹(Western Blot)磷酸化蛋白的标记。首先通过反相微乳液Stöber方法合成了掺杂异硫氰酸荧光素硅烷化衍生物的发光二氧化硅(FITC@SiO_(2))球形纳米粒子,粒子平均粒径为60 nm。然后通过共聚反应在FITC@SiO_(2)纳米粒子表面生成一层聚合物用于保护纳米粒子,并引入N,N-(双羧甲基)-L-赖氨酸功能基团用于螯合金属离子,从而实现固定化金属离子亲和作用。以α-酪蛋白作为实验模型,用高效液相色谱-质谱研究了螯合不同金属离子的发光纳米粒子对磷酸化蛋白的识别作用。结果表明,螯合了Ti^(4+)金属离子的发光二氧化硅FITC@SiO_(2)纳米粒子对α-酪蛋白酶解液中的磷酸化肽段的富集作用最强。利用这种发光二氧化硅FITC@SiO_(2)纳米粒子对磷酸化肽段的特异性识别性能,可用于Western Blot实验中标记磷酸化蛋白的条带。结果显示,α-酪蛋白的电泳条带可以被亲和发光二氧化硅FITC@SiO_(2)纳米粒子标记,而作为对照的牛血清白蛋白则没有被标记。

Nb2O5包覆对TiO2纳米阵列/上转换发光复合结构柔性染料敏化太阳能电池性能的影响

采用水热法与旋涂法,成功制备出基于钛网基底的TiO2纳米线阵列/Yb-Er-F掺杂TiO2上转换发光纳米粒子(TNWAs/YEF-TiO2-UCNPs)复合结构光阳极,并将其组装成柔性染料敏化太阳能电池(DSSC)。探讨了Yb-Er-F掺杂TiO2上转换发光纳米粒子的光学性能对复合结构DSSC光电转换性能的影响,在此基础上系统研究了不同NbCl5浓度包覆对复合结构形貌和DSSCs性能的影响。结果表明:Yb-Er-F掺杂TiO2上转换发光纳米粒子的引入可以增大光阳极的入射光利用范围,但同时也会增加其内部的电子复合。通过Nb2O5纳米粒子层的包覆可以在半导体/电解液界面形成能量势垒,增加复合阻抗Rrec,抑制电子复合;提高电子收集效率ηec和光生电子寿命τe,进一步增大短路电流和开路电位,最终提高电池的光电转换效率。采用20mmol/L的NbCl5乙醇溶液旋涂制备的Nb2O5@TNWAs/YEF-TiO2-UCNPs复合结构柔性DSSC获得了最佳的光电转换效率(6.89%),比未经包覆的TNWAs/YEF-TiO2-UCNPs复合结构提升了24.3%。

纳米标记免疫层析法在农药残留检测中的应用研究进展

农药残留超标已成为影响农产品质量安全的重要问题,迫切需要探寻开发灵敏、准确、可靠、便捷且适用性强的农药残留快速检测方法。免疫层析法是将抗原抗体特异性免疫反应和色谱层析分离技术相结合的一种快速检测方法,其中,基于胶体金标记的免疫层析技术以其便捷、成本低、可视化等优点而受到普遍欢迎。近年来随着量子点、时间分辨荧光微球、上转换发光纳米粒子等新型纳米标记材料的出现,免疫层析技术得到了广泛发展。文章从标记类型(非共价作用标记及共价作用标记)及标记材料(胶体金、纳米碳、量子点、上转换发光纳米粒子、磁性纳米颗粒、时间分辨荧光微球及荧光乳胶颗粒)等方面,综述了不同纳米材料标记的免疫层析技术及其在农药残留检测领域的研究及应用进展,可为深入开展农药残留免疫层析技术研究提供参考。

纳米晶体自组装结构中非辐射能量传递过程的验证

以上转换纳米粒子NaYF_(4)∶20%Yb,2%Er@NaYF_(4)(标记为UCNP)和金纳米粒子(AuNP)分别作为能量传递研究的给体和受体,研究在具有确定位置关系的组装结构中二者之间的非辐射能量传递是否存在。以UCNP和AuNP作为基本构建单元,采用气-液界面溶剂挥发法,得到了连续大面积规整排列的二维UCNP单层自组装膜。再通过层层组装得到UCNP+AuNP双层膜、UCNP+NaYF_(4)+AuNP三层膜。利用自行搭建的光谱成像系统对自组装结构进行了发光性质测试。对比3种膜结构的发光情况,发现UCNP+AuNP双层膜和UCNP+NaYF_(4)+AuNP三层膜的发光与UCNP单层膜减弱幅度相近,即在我们研究的体系中UCNP和AuNP之间不存在明显的非辐射能量传递过程。本研究提供了一种几何关系明确的组装体模型,并搭建了相应的微区发光性质测试设备,验证了在我们设计的自组装模型中并不存在UCNP与AuNP的非辐射能量传递。

Size Control of Nanoscale Silicon Particles Formed in Thermally Annealed A-Si∶H Films and Its Photoluminescence

A method to control the size of nanoscale silicon grown in thermally annealed hydrogenated amorphous silicon （a-Si：H） films is reported. Using the characterizing techniques of micro-Raman scattering, X-ray diffraction and computer simulation, it is found that the sizes of the formed silicon particles change with the temperature rising rate in thermally annealing the a-Si ： H films. When the a-Si：H films have been annealed with high rising rate（～100℃/s）, the sizes of nanoscale silicon particles are in the range of 1.6～15nm. On the other hand, if the a-Si：H films have been annealed with low temperature rising rate（～1℃/s）, the sizes of nanoscale silicon particles are in the range of 23～46nm. Based on the theory of crystal nucleation and growth, the effect of temperature rising rate on the sizes of the formed silicon particles is discussed. Under high power laser irradiation, in situ nanocrystallization and subsequent nc-Si clusters are small enough for visible light emission, authors have not detected any visible photoluminescence（PL） from these nc-Si clusters before surface passivation. After electrochemical oxidization in hydrofluoric acid, however, intense red PL has been detected. Cyclic hydrofluoric oxidization and air exposure can cause subsequent blue shift in the red emission. The importance of surface passivation and quantum confinement in the visible emissions has been discussed.

Enhancement effect of terbium complex luminescence by binding to silver nanoparticles in the solution

The luminescent properties of terbium complex (terbium citrate) by binding to silver nanopartilces in the solution have been reported in this paper.The enhanced luminescence of the complex containing silver nanoparticles was observed at a limited particle concentration region.The nanoparticle concentration dependence of the luminescent intensity was regarded as the result of a delicate balance between an enhancing and a quenching effect of the silver nanoparticles.Furthermore,silver nanoparticles also affected the asymmetric ratio (AS) value of terbium luminescence.We discuss the luminescent properties of the terbium complex in terms of the local electromagnetic field,refractive index,and the ligand field around terbium ion.

The intensification of luminol electrochemiluminescence by metallic oxide nanoparticles

In this work, the intensification of luminol electrochemiluminescence (ECL) by metallic oxide nanoparticles (MONPs), as ZnO, MnO2,In2O3 and TiO2 , under alkaline condition is reported and the related mechanism is studied. It is found that all four types of those MONPs exhibit the effect toward the ECL intensification of luminol. Furthermore, the silica sol-gel film is taken to immobilize the MONPs onto the platinum electrodes. The so-obtained modified electrodes also show the enhanced ECL and better signal/noise ratio, as well improved signal stability. Finally, the ECL reagent, luminol, is immobilized together with the MONPs onto the electrode surface to perform as the ECL sensor. On resulting sensors, good linear responses are obtained toward hydrogen peroxide. The mechanism of intensification of luminol ECL by MONPs is discussed in this paper. It is proposed that the ECL intensification can be attributed to the production of reactive oxygen species, as well as the adsorption of luminol on surface of MONPs.

A novel strategy for improving upconversion luminescence of NaYF4：Yb, Er nanocrystals by coupling with hybrids of silver plasmon nanostructures and poly（methyl methacrylate） photonic crystals

The coupling of upconversion nanophosphors （UCNPs） with the surface plasmonic resonance （SPR） of noble metals is a promising way to improve luminescent efficiency of UCNPs; however, it is still a challenge to achieve stable, reproducible and effective upconversion luminescence （UCL） enhancement through such coupling. In this work, we present a novel strategy to improve UCL of NaYF4：ybB,Er3. UCNPs, by combining the near-field coupling of SPR of silver and the far-field coupling of poly（methyl methacrylate） （PMMA） opal photonic crystals （OPCs） with the UCNPs. In order to control the effective interaction distance between the UCNPs and the SPR, a porous silver film consisting of randomly distributed silver nanoparticles （NPs） （〉 100 nm） was prepared which demonstrated strong SPR over a broad wavelength range, and its coupling to the UCNPs was found to be much stronger than that of a dense film. In the far-field coupling of OPCs, the photonic stop band （PSB） of the PMMA OPCs was tuned to 980 nm, matching exactly the excitation light. By modulating the particle size of the UCNPs, and the direction and excitation power of the incident light, a maximum enhancement of 60-fold was observed, which is an important advance for metaMnduced UCL enhancement systems.

One-step preparation of branched PEG functionalized AIE-active luminescent polymeric nanoprobes

The synthesis of amphiphilic aggregation-induced emission （ALE） dyes based organic nanoparticles has recently attracted in- creasing attention in the biomedical fields. These AlE dyes based nanoparticles could effectively overcome the aggregation caused quenching effect of conventional organic dyes, making them promising candidates for fabrication of ultrabright organic luminescent nanomaterials. In this work, AIE-active luminescent polymeric nanoparticles （4-NH2-PEG-TPE-E LPNs） were facilely fabricated through Michael addition reaction between tetraphenylethene acrylate （TPE-E） and 4-arm-poly（ethylene glycol）-amine （4-NH2-PEG） in rather mild ambient. The 4-NH2-PEG can not only endow these AlE-active LPNs good water dispersibility, but also provide functional groups for further conjugation reaction. The size, morphology and luminescent prop- erties of 4-NH2-PEG-TPE-E LPNs were characterized by a series of techniques in detail. Results suggested that these AlE-active LPNs showed spherical morphology with diameter about 100-200 nm. The obtained 4-NH2-PEG-TPE-E LPNs display high water dispersibility and strong fluorescence intensity because of their self assembly and AlE properties of TPE-E. Biological evaluation results demonstrated that 4-NH2-PEG-TPE-E LPNs showed negative toxicity toward cancer cells and good fluorescent imaging performance. All of these features make 4-NHz-PEG-TPE-E LPNs promising candidates for biolog- ical imaging and therapeutic applications.

Electrogenerated chemiluminescence aptasensor for thrombin incorporating poly(pyrrole-co-pyrrole propylic acid) nanoparticles loaded with aptamer and ruthenium complex

A novel electrogenerated chemiluminescence （ECL） aptasensor for highly sensitive detection of thrombin was developed on the basis of poly（pyrrole-co-pyrrole propylic acid） nanoparticles loaded with aptamer and ruthenium complex. Thrombin binding aptamers served as the molecular recognition elements and ruthenium bis（2,2＇-bipyridine） （2,2＇-bipyridine-4,4＇-dicarboxylic acid）-ethylenediamine （Rul） was used as an ECL signal complex. Novel electroactive polymers poly（pyrrole-co-pyr- role propylic acid） nanoparticles （Ppy-pa NPs） were synthesized by a simple alcohol-assisted microemulsion polymerization. Rul-Ppy-pa NPs were synthesized by covalently coupling Rul with the Ppy-pa NPs. Ppy-pa NPs and Rul-Ppy-pa NPs were characterized using a fourier transform infrared spectrometer, super-conducting fourier digital NMR spectrometer, and trans- mission electron microscope. One ECL chemical sensor fabricated by immobilizing the Rul-Ppy-pa NPs on PIGE was developed for the determination of TprA with a high sensitivity and stability. The ECL aptasensor was fabricated by covalenfly coupling the thrombin binding aptamer-I （TBA-I） onto the surface of the paraffin-impregnated graphite electrode, which had been covalently modified with a monolayer of 4-aminobenzene sulfonic acid via electrochemical oxidations, for capturing thrombin onto the electrode and then the TBA-II labeled with Rul-Ppy-pa NPs was bound with epitope of thrombin. The ECL aptasensot showed an extremely low detection limit of 3.0×10^-16 mol/L for thrombin and a good selectivity. This work demonstrated that using Ppy-pa NPs as a carrier of ruthenium complex and molecular recognition element was a promising approach for the fabrication of ECL biosensor with high sensitivity.

NIR-to-NIR UCL/T_1-weighted MR/CT multimodal imaging by NaYbF_4:Tm@NaGdF_4:Yb-PVP upconversion nanoparticles

Multimodal imaging nanoprobes are urgently sought because they can integrate different imaging func- tion into individual nanoplatform and provide more comprehensive and accurate information for the diagnosis of early-stage tumor. Lanthanide-based upconversion nanoparticles （UCNPs） are regarded as promising nanoplatforms to fabricate these probes. Herein, we firstly developed the active core-active shell structured NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs with the average diameter of 13.23 ＋ 0.96 nm as multimodal imaging probes. These water-dispersible nanoprobes presented excellent near-infrared to near-infrared （NIR-to-NIR） upconversion luminescence （UCL） performance, which is favorable for optical bioimaging due to deeper tissue penetration and autofluorescence reduction. After coated with the NaGdF4：Yb active shell, the UCL emission intensity at 800 nm increased by 7.2 times. These nanoprobes exhibited a desirable longitudinal relaxivity （rl = 3.58 L/（mmol s）） and strong X-ray attenuation property （58.84 HU L/g）. The cytotoxicity assessment, histology analysis and biodistribution study revealed that NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs had relatively low cytotoxicity and negligible organ toxicity. These UCNPs were applied for NIR-to-NIR UCL imaging in vivo. More importantly, the detection of small tumor was successfully achieved under Trweighted MRI and CT imaging modalities after intravenous injection of these UCNPs. These results revealed that NaYbF4：Tm@NaGdF4：Yb-PVP UCNPs could serve as promising NIR-to-NIR UCL/MRI/CT trimodal imaging probes.