基于氨光化学响应的有机杂化溶胶-凝胶膜

研究了基于有机杂化硅氧烷的氨光化学传感器；实验通过四甲氧基硅烷（TMOS）和二甲基二甲氧基硅烷（DiMe-DMOS）的缩聚，获得以氨基荧光素（AF）为荧光指示探针，对氨有灵敏荧光响应的溶胶－凝胶敏感膜；实验考察了溶胶先驱体、各种比例杂化硅氧烷在玻璃支撑体上成膜后对体系pH、NH3浓度和响应时间的变化规律，发现DiMe-DMOS含量的变化改变杂化膜的极性，并使得敏感性对NH3有高荧光响应值，而对体系的pH不响应；实验结果表明在pH8.4，0.1mol/L磷酸盐缓冲溶液中，氨质量浓度与其相应的荧光强度在0．5－60mg/L范围内呈良好的线性关系，敏感膜对NH3的95％响应时间为4min，常见的共存物质如氨基酸、胺和金属离子对NH3测定未见有明显的干扰。     

纳米金和荧光DNA的腺苷和钾离子一体化检测（英文）

利用具有不同荧光修饰的寡聚核苷酸(DNA)作为响应基团、纳米金粒子作为淬灭基团构建了多组分"turn-on"传感器,从而达到制备便捷、检测快速且灵敏,同时尽量减少干扰的目的。由于不同检测物识别序列的互补链上修饰的荧光基团不同,可通过不同的荧光达到对不同检测物检测的目的。利用此原理构建了针对腺苷和钾离子的传感器,对腺苷的检出限达387.9 nmol/L,检测范围0～15μmol/L,通过调节识别序列检测范围可提高到mmol/L级别;对钾离子的检出限达1.6μmol/L,检测范围2～6μmol/L。     

异硫氰酸荧光素功能化金纳米荧光法检测硫普罗宁

通过自组装方式获得了异硫氰酸荧光素修饰的金纳米,硫普罗宁上的巯基能够与异硫氰酸荧光素竞争性争夺金纳米表面,导致部分异硫氰酸荧光素远离金纳米,绿色荧光恢复,基于此构建了可用于高灵敏检测硫普罗宁的荧光传感器。汞离子的干扰可以通过EDTA进行掩蔽,有效消除干扰。传感器对硫普罗宁的线性检测范围为1. 0～750 nmol/L和1. 0～10. 0μmol/L,检出限为0. 85 nmol/L。     

甲胎蛋白光寻址电位式传感器的研究

研究了基于光寻址电位传感器(LAPS)的无标记甲胎蛋白免疫检测。采用共价交联的方法在光寻址电位传感器的敏感膜表面固定甲胎蛋白抗体,根据蛋白质分子特异性结合会引起膜电位变化进行检测;对度为400μg/L甲胎蛋白抗原的响应约为11mV;不同浓度的甲胎蛋白抗原的响应同浓度呈线性关系,线性相关系数为0．9996;各个芯片对不同浓度AFP膜电位响应的相对标准偏差小于6％。验证了采用光寻址电位传感器技术检测甲胎蛋白的可行性,为多参数蛋白质芯片的研究提供了理论和实验数据。     

一种用于水样检测的快速汞离子荧光传感器

在440 nm激发波长下,核黄素水溶液在525 nm处能够产生荧光,汞离子(Hg2+)存在时其荧光被猝灭,基于此开发了一种用于水样中Hg2+浓度快速检测的荧光传感器。该传感器对Hg2+的检测线性范围是50 nmol/L～50μmol/L,检出限是8.0 nmol/L,响应迅速(约1 min),对其他金属离子具有很好的选择性,将其应用于湖水中Hg2+检测结果满意。     

精氨酸-罗丹明类Pb~(2+)荧光探针合成及识别性能

以罗丹明B、水合联氨、精氨酸为原料,合成了精氨酸-罗丹明类荧光探针化合物。利用红外光谱、核磁等技术对探针结构进行表征,利用荧光光谱研究其光谱性能及对金属离子的识别性能,同时也考查了金属离子浓度等因素的影响。结果表明,合成的荧光探针在乙腈/水溶液(1:3,V/V)中能对Pb~(2+)有较高的选择识别性能,且受常见金属离子的干扰较小,探针的荧光强度与Pb~(2+)浓度(11.50~27.56μmol/L)呈较好的线性关系,相关系数R~2=0.992,检出限为9.91μmol/L。Job’s曲线表明,荧光探针与Pb~(2+)的络合比为1:1,同时探讨了探针响应机理。     

聚丙烯酸/萘酰亚胺纳米粒荧光增强法测定蛋白质

制备了水溶性的聚丙烯酸/萘酰亚胺荧光纳米粒,并利用牛血清白蛋白(BSA)对其荧光的显著增强效应,建立了测定蛋白质的新方法。在pH=3.0磷酸盐缓冲溶液及室温条件下,该纳米粒与BSA的作用5 min内即完成。以444nm为激发波长,在535nm处测定纳米粒/BSA体系的荧光,其荧光强度增加与0.15~7.5μmol·L-1浓度范围内的BSA呈线性关系,检测限为0.095μmol·L-1。该方法简单、快速、灵敏且重现性好,用于BSA合成样品及牛奶样品中蛋白质的测定,回收率范围为96.7%~102.6%,相对标准偏差(RSD)在3.91%以内。     

荧光猝灭法和动态光散射法研究尿素-水混合溶剂中牛血清 白蛋白的构象变化

利用荧光猝灭法和动态光散射法测定尿素-水混合溶剂中牛血清白蛋白(BSA)与荧光素的结合距离和BSA的流体动力学半径, 并通过分析BSA和荧光素在BSA-尿素-水和荧光素-尿素-水三元体系以及BSA-荧光素-尿素-水四元体系中荧光光谱的变化, 探讨尿素与蛋白质分子在水溶液中相互作用的机理及其对蛋白质构象的影响. 结果显示, BSA的3个结构域在尿素-水混合溶剂中具有不同的稳定性, 其中结构域III在尿素-水混合溶剂中是不稳定的, 而结构域I和结构域II分别在尿素浓度大于3.0和4.0 mol•L－1的混合溶剂中发生去折叠. 试验发现, BSA结构域II在低于去折叠浓度的尿素-水混合溶剂中形成更为紧密的构象, 这一现象可以归因于尿素与BSA结合引起的“蛋白质粘稠效应”     

基于电流脉冲沉积法的硝酸根微传感器研究

基于微加工技术(Microfabrication technology)制备微传感电极并进行电化学表面修饰,研制出一种用于水体中NO#3浓度检测的电化学微传感器。微传感器以两电极传感芯片为信号转换部件,使用电流脉冲沉积法在铂质工作电极表面制备微观形貌呈枝簇状的铜质敏感材料,利用铜质材料对酸性溶液中NO#3的电催化还原特性,测量还原电流的大小,实现对NO#3浓度的检测。采用扫描电子显微镜(SEM)和X射线衍射分析(XRD)技术对敏感膜进行表征和监测,探索高活性铜质敏感膜的制备方法;使用微传感器对硝酸盐标准样品进行检测,在低浓度范围(12.5~200μmol/L),响应灵敏度为0.1422μA/(μmol/L);高浓度范围(200~3000μmol/L),响应灵敏度为0.0984μA/(μmol/L),均表现出较高的检测灵敏度;使用微传感器对北京等地的实际湖库水样进行检测,结果与专业水质检测机构采用紫外分光光度法的测试结果偏差在#3.9%~15.4%之间,两者具有一定的相关性,表明微传感器能够用于实际水样中NO#3浓度的测量。     

基于金纳米簇检测碘单质的荧光分析方法研究

以蛋白质保护的金纳米簇Au NCs@BSA作为荧光探针,高灵敏地检测碘含量。结果表明,碘单质可引起金纳米簇的荧光猝灭,在2.0 nmol/L~35μmol/L浓度范围内具有良好的线性响应关系,检出限为1.8nmol/L。利用建立的方法对水样中的碘单质进行定量测定,并与ICP-MS检测结果进行对比,结果证明该方法在实际样品的检测中具有应用潜力。同时基于Au NCs@BSA与碘浓度的依赖效应,改变温度,诱导荧光响应变化,利用热力学计算,深入探讨了Au NCs@BSA与碘单质之间的作用机理,圆二色谱与红外光谱的结果表明碘单质引起的配体BSA的蛋白二级结构变化,诱导了Au NCs@BSA的荧光猝灭。该文的机理研究为无机小分子与蛋白质保护的金纳米簇之间的相互作用提供了参考。     

Proton "off-on" behaviour of methylpiperazinyl derivative of naphthalimide: a pH sensor based on fluorescence enhancement

In a search for new type pH sensing fluorophores, the possibility of using the proton "off-on" switch behaviour of naphthalimide derivatives for optical pH sensor preparation has been explored. A new compound, N-allyl-4-(4[prime or minute]-methyl-piperazinyl)-1,8-naphthalimide (AMPN), was synthesized. The enhancement of fluorescence of AMPN with the increase of hydrogen ion concentration is based on arresting photo-induced electron transfer to the naphthalimide fluorophore from aliphatic amine group after its protonation. The Stokes Shift of the proposed type of pH sensing fluorophore is significantly larger than that of the fluorescein counterparts. To avoid the leakage of the fluorophore, AMPN was photo-copolymerized with 2-hydroxyethyl methacrylate and acrylamide on the glass surface. The fluorescence intensity of membrane contacted with a pH 3.50 buffer is 4.7 times of that for pH 12.00 buffer solutions. The proposed pH sensor is not susceptible to ionic strength and shows good selectivity, repeatability and short response time. The membrane shows a good stability with a lifetime over two months. The sensor can be used for the determination of pH in the range of pH 4.5-9.0, without interference of most commonly co-existing inorganic ions and some organic species. The sensor has been applied to the analysis of urine samples.     

Fluorescence ratiometric pH sensor prepared from covalently immobilized porphyrin and benzothioxanthene

A fluorescence ratiometric sensor for pH determination is described in this paper. The sensor incorporated the pH-sensitive dye meso-5,10,15,20-tetra-(4-allyloxyphenyl)porphyrin (TAPP) as an indicator and a pH-insensitive dye N-(2-methacryloxyethyl)benzo[k,l]thioxanthene-3,4-dicarboximide (MBTD), a benzothioxanthene derivative, as a reference for fluorescence ratiometric measurement. To prevent leakage of the dyes, both were photocopolymerized with acrylamide, hydroxyethyl methacrylate, and triethylene glycol dimethacrylate on the silanized glass surface. The reproducibility and response time of the prepared sensor were sufficient. Most common coexisting inorganic ions and organic compounds did not interfere with pH sensing. In the acidic pH range from 1.5 to 5.0 the fluorescence intensity ratio of the two dyes varied linearly as a function of pH. The sensing membrane was found to have a lifetime of at least one month. The sensor was applied to the analysis of waste water and artificial samples.     

A wide pH range optical sensing system based on a sol-gel encapsulated amino-functionalized corrole

The synthesis of a new compound, 10-(4-aminophenyl)-5,15-dimesitylcorrole, and its application for the preparation of optical chemical pH sensors is described. The dye materials were immobilized in a sol-gel glass matrix and characterised upon exposure to aqueous buffer solutions. The response of the sensor is based on the fluorescence intensity changing of corrole owing to multiple steps of protonation and deprotonation. Due to its containing several proton sensitive centers, the 10-(4-aminophenyl)-5,15-dimesitylcorrole based optode shows a wider response range toward pH than that of tetraphenylporphyrin (TPPH(2)) and 5,10,15-tris(pentafluorophenyl)corrole (H(3)(tpfc)). It shows a linear pH response in the range of 2.17-10.30. The effect of the composition of the sensor membrane has been studied and the experimental conditions were optimized. The optode showed good reproducibility and reversibility, and common co-existing inorganic ions did not show obvious interference to its pH measurement.     

Protein-gold nanoclusters for identification of amino acids by metal ions modulated ratiometric fluorescence

Here we report that the dual fluorescence emissions from protein-gold (Au) nanoclusters can greatly be modulated by metal ions and the resultant fluorescence ratiometric responses provide a novel sensory method for the identification of amino acids. The protein-gold (Au) nanoclusters were simply synthesized by the reduction of chloroauric acid with bovine serum albumin (BSA), which exhibit dual emissions: the blue at 425 nm from the oxides of BSA, and the red at 635 nm from Au nanoclusters. It has been demonstrated that different metal ions react with BSA-Au nanoclusters and thus greatly affect the two emissions in different ways by fluorescence enhancement or quenching. Interestingly, the addition of amino acids leads to fluorescence ratiometric changes through the interactions with the bound metal ions. When BSA-Au nanocluster probes modulated by four different metal ions were used together to construct a sensor array, different amino acids were clearly discriminated by the distinctive patterns of four ratiometric fluorescence responses. Results and methods reported here provide a unique strategy for the determination of amino acids.     

A long lifetime chemical sensor: study on fluorescence property of fluorescein isothiocyanate and preparation of pH chemical sensor

The fluorescence property of fluorescein isothiocyanate (FITC) in acid-alkaline medium was studied by spectrofluorimetry. The characteristic of FITC response to hydrogen ion has been examined in acid-alkaline solution. A novel pH chemical sensor was prepared based on the relationship between the relative fluorescence intensity of FITC and pH. The measurement of relative fluorescence intensity was carried out at 362 nm with excitation at 250 nm. The excellent linear relationship was obtained between relative fluorescence intensity and pH in the range of pH 1-5. The linear regression equation of the calibration graph is F = 66.871 + 6.605 pH (F is relative fluorescence intensity), with a correlation coefficient of linear regression of 0.9995. Effects of temperature, concentration of FITC on the response to hydrogen ion had been examined. It was important that this chemical sensor was long lifetime, and the property of response to hydrogen ion was stable for at least 70 days. This pH sensor can be used for measuring pH value in water solution. The accuracy is 0.01 pH unit. The results obtained by the pH sensor agreed with those by the pH meter. Obviously, this pH sensor is potential for determining pH change real time in biological system.     

蛋白质对溴鼠灵的荧光增敏及分析应用

实验发现, 牛血清白蛋白可以大大增强杀鼠剂溴鼠灵的荧光. 利用荧光猝灭法考察了溴鼠灵和牛血清白蛋白的相互作用. 结果表明溴鼠灵对牛血清白蛋白的内源荧光有较强的猝灭作用, 两者形成了新的复合物, 属于静态荧光猝灭. 跟据荧光增敏现象, 建立了水溶液中测定溴鼠灵的荧光方法. 在优化实验条件下, 线性范围为5.0×10-8～4.0×10-7 mol/L和4.0×10-7～1.5×10-5 mol/L, 检出限为5.9×10-9 mol/L. 该方法用于渠水中微量溴鼠灵的测定, 回收率为94.1%～101.3%.     

一种高灵敏度高选择性的荧光素基比色荧光锌传感器

本文报道了一种基于荧光素的锌离子传感器FN1,其在甲醇溶液中显示了对锌离子极高的灵敏度和选择性。随着锌离子的滴加,紫外-可见光谱中最初在371 nm处的吸收峰消失,在437 nm处出现了一个新峰。当在混合金属离子的甲醇溶液中滴加了相对于二价金属离子的等物质的量浓度的锌离子或相对于一价金属离子0.5倍物质的量浓度的锌离子后,锌离子积分荧光强度增强了近37倍（Φ=0.48,λ_max(em)=513 nm）,估算的锌离子检测限为7 μg·L^-1。基于紫外-可见光、荧光和质谱的结果,讨论了1∶1的FN1/Zn²⁺配合物的结合机理。     

Spatially inhomogeneous enhancement of fluorescence by a monolayer of silver nanoparticles

Near-field scanning optical microscopy (NSOM) was applied to study the effect of a two-dimensional array of silver nanoparticles on the spatial distribution and magnitude of fluorescence signal enhancement for a monolayer of Rhodamine 6G (Rh6G). Twenty polyelectrolyte monolayers were deposited between the nanoparticles and the dye by a layer-by-layer deposition technique resulting in a 15-20 nm separation cushion, necessary to minimize the fluorescence signal quenching. The fluorescence signal in NSOM images was found to be distributed inhomogeneously as small (100-200 nm in diameter) fluorescent clusters with typically 5-30 times higher fluorescence intensities than a sample without nanoparticles. The position and relative intensity of the clusters was found to be dependent on the excitation wavelength, suggesting that the enhancement originates from the nanoparticle surface plasmon resonance.     

光谱法研究噻菁染料与血清蛋白的相互作用

本文通过吸收和荧光光谱法研究了一种噻菁染料与人血清蛋白及牛血清蛋白的相互作用。吸收光谱数据表明,与血清蛋白结合后,噻菁染料单体的吸收峰发生红移,同时强度也有很大变化;还通过吸收光谱计算确定了噻菁染料与血清蛋白的结合位点数（ n ）。与人血清蛋白或牛血清蛋白结合后,噻菁染料的荧光量子产率增加。分析噻菁染料的荧光强度随溶液中血清蛋白浓度的变化得到了二者反应的表观结合常数（ K _a）和自由能变化（ ΔG ）。根据表观结合常数（ K _a）可以判断,人血清蛋白比牛血清蛋白与噻菁染料的结合更强。     

基于氮掺杂碳点的荧光增强简便、快速而准确地检测环丙沙星

以苹果酸为碳源,磷酸铵提供氮源,采用固态热解法一步合成一种水溶性的、氮掺杂的蓝色荧光碳点(N-CDs)。 所得到的碳点荧光量子产率高达20.7%,形貌近似球形,平均粒径约为3.3 nm。 基于环丙沙星(CIP)对碳点的荧光增强作用,建立了一种CIP的定量检测方法。 最佳实验参数为:碳点浓度为7.5 μg/mL,pH值为5.9,孵化时间为5 min。 在此实验条件下,碳点的荧光强度增加值(ΔF)和CIP的浓度在0.39~40.00 μmol/L范围内呈良好的线性关系,方法的检出限为0.12 μmol/L,相对标准偏差(n=5)为4.2%。 干扰实验结果指出,除了铜离子具有明显的影响外,其它共存物质的干扰可以忽略不计,而铜离子的干扰可通过加入草酸铵来掩蔽。 最后利用所构建的荧光传感器对实际样品中CIP进行检测,回收率在93%~107%之间。 本研究为CIP定量分析提供了一种简单、快速、灵敏度高、选择性好而有效的测定方法。