适配体修饰金硒纳米合金共振散射光谱法检测痕量Hg2+

用硼氢化钠还原法制备了金硒(AuSe)纳米合金.用单链核酸适配体(aptamer)修饰AuSe纳米合金制备了汞离子的核酸适配体纳米探针(Apta-AuSe).在pH 6.8 Na2HPO4-NaH2PO4缓冲溶液中及NaCl存在下,Apta-AuSe纳米探针亦不聚集;当Hg2+存在时,它可以稳定aptamer序列中的T...     

用适配体修饰纳米金做共振瑞利散射光谱探针检测妥布霉素

用硼氢化钠还原氯金酸制备了金纳米粒子(GN),用妥布霉素适配体(Apt)修饰GN可获得较稳定的Apt-GN探针。在pH 6.8 Na₂HPO₄-NaH₂PO₄(PBS)缓冲液及NaCl存在下,Apt-GN探针稳定而不聚集;当有妥布霉素(Tbc)存在时,它与Apt-GN探针中的Apt特异性结合并释放出纳米金,纳米金在NaCl作用下聚集,导致体系在368 nm处的共振瑞利散射光增强。在选定实验条件下,368 nm处的共振散射峰强度的增大值ΔI与抗生素妥布霉素(Tbc)浓度在1.9～58.3 ng·mL-1范围内呈良好线性关系,其线性回归方程为ΔI=35.3c-23,检出限为0.8 ng·mL-1 妥布霉素。分别对10.0,20.0和30.0 ng·mL-1 Tbc平行测定5次,求得其相对标准偏差分别为6.8%,5.0%和4.4%。考察了共存离子对测定38.9 ng·mL-1 妥布霉素的干扰情况。结果表明,当相对误差在±10%以内,80倍Zn2+;40倍L-谷氨酸,Cu2+,Mg2+,Ca2+;20倍葡萄糖、盐酸土霉素;10倍L-苯丙氨酸、甘氨酸;2倍L-天冬氨酸;6倍HSA和BSA不干扰测定。这说明本方法具有较好的选择性。该法用于分析测定妥布霉素滴眼液中的妥布霉素含量,结果令人满意,相对标准偏差在6.5%～7.6%之间,回收率在95.0%～107%之间。     

一个检测痕量汞离子的鱼精DNA修饰纳米金共振散射光谱法

在pH 7.0 Tris-HCl缓冲溶液及0.017 mol.L-1NaCl介质中,鲱鱼精DNA与10 nm的金纳米粒子形成较稳定的结合物使得金纳米粒子不聚集,体系的散射信号较弱。当有Hg2+存在时,DNA与Hg2+形成更稳定的DNA-Hg2+结合物,金纳米粒子聚集导致572 nm处的共振散射峰增强。在3.87μg.mL-1金纳米粒子-11.7μg.mL-1DNA-pH 7.0~17 mmol.L-1NaCl条件下,Hg2+浓度c在3.3~3 333.3 nmol.L-1范围内与572 nm处的共振散射强度增强值ΔI572 nm成良好线性关系,其回归方程、相关系数、检出限分别为ΔI572 nm=0.019c+5.0,0.999 1,2.5 nmol.L-1。该法用于水样分析,结果与冷原子吸收光谱法一致,相对标准偏差为5.1%。     

DNA酶裂解-纳米金共振瑞利散射光谱法测定痕量Cu2+

在pH 7.0HEPES(4-羟乙基哌嗪乙磺酸)缓冲溶液中和0.19mol.L-1 NaCl存在下,单链底物DNA(SS)和酶链DNA(ES)在80℃杂交形成双链DNA(dsDNA)。Cu2+可切割dsDNA中的底物链释放出单链DNA(ssDNA),此ssDNA与金纳米粒子(NG)作用形成NGssDNA结合物不被NaCl聚集,而未保护的NG聚集形成较大粒径的聚集体(NGA),在627nm处有一个较强的共振瑞利散射峰。随着Cu2+浓度的增大,该共振瑞利散射峰降低,其降低值ΔI与Cu2+浓度在15～1 250nmol.L-1范围呈线性关系,其回归方程为ΔI=0.17c-2.3,线性相关系数为0.989 5,检出限为8nmol.L-1。据此建立了一个高灵敏、高选择性、简便测定Cu2+的共振瑞利散射光谱分析法。该法用于水样中Cu2+的检测,结果满意。     

共振散射光谱法测定药物制剂中盐酸氯丙嗪的含量

在弱酸性溶液中,盐酸氯丙嗪与十二烷基苯磺酸钠反应形成离子缔合物,导致体系的共振散射（RS）强度急剧增强,并产生新的共振散射光谱,最强散射波长为466nm。本文研究了体系的光谱特征、反应的适宜条件和共存物质的影响。在466nm处,盐酸氯丙嗪的浓度在0.266—12.8μg/mL范围内与体系的散射强度有良好的线性关系,检出限（3σ）为0.056μg/mL。据此,建立了一种测定盐酸氯丙嗪含量的简便、快速、高灵敏的共振散射新方法,且已用于盐酸氯丙嗪片剂和针剂中含量的测定,结果满意。     

适配体纳米金比色分析技术研究进展

核酸适配体作为一种生物识别分子,其本质是一段单链DNA或RNA,折叠形成特定的二级、三级构象后与靶标分子以高亲和力高特异性结合。纳米金具有强烈的粒子间距光学效应,其在分散状态下呈红色,发生凝聚后变为蓝色。适配体可以通过共价偶联或静电吸附与纳米金结合,通过结合靶标来控制纳米金的颜色变化,从而提供了一种简单、快速、灵敏、可以肉眼观察的快速分析技术。综述了适配体纳米金比色分析技术的研究进展,通过对不同方法比较和讨论,提出了未来的研究方向。     

聚乙二醇光化学法制备金纳米微粒及共振散射光谱研究

采用共振散射光谱、紫外-可见吸收光谱、透射电镜对聚乙二醇(PEG)-Au3+纳米光化学反应进行了研究。讨论了金纳米粒子合成条件的影响,发现金纳米粒子的尺寸与PEG分子量大小有关。建立了一个利用不同分子量PEG制备一系列粒径为6～60 nm金纳米粒子的光化学合成新方法。根据PEG分子的空间位阻、疏水性等解释了PEG分子量不同而获得不同粒径金纳米粒子的原因。提出了一个合理的纳米光化学反应机理。     

十二烷基苯磺酸钠共振散射光谱法测定木瓜蛋白酶活力

在pH值6.5的磷酸盐缓冲溶液中,十二烷基苯磺酸钠(SDBS)与酪蛋白(Casein)形成缔合物微粒,在470,360,400,420和520 nm产生5个瑞利散射峰。在选定条件下,木瓜蛋白酶(Papain)可水解酪蛋白(Casein),加SDBS可中止酶催化反应并与未反应的酪蛋白底物结合形成缔合物微粒。随着Papain浓度的增大,470 nm处的共振散射峰强度降低。Papain的酶活力在0.048～4.8 USP·mL-1范围内与ΔI_{470 nm}呈现良好的线性关系。其线性回归方程为ΔI_SDBS=1.972c+2.31,相关系数分别为r=0.999 9,检测限为0.020 USP·mL-1。该法用于嫩肉粉中木瓜蛋白酶活力测定,结果令人满意。     

一种检测痕量IgG的免疫纳米银共振散射光谱探针

以柠檬酸三钠作还原剂,采用微波高压合成法制备了粒径约为20 nm的银纳米微粒。在pH 9.0条件下,用银纳米微粒标记羊抗人IgG制备了IgG的免疫纳米银探针(AgGIgG)。在pH为6.0的磷酸盐缓冲溶液及聚乙二醇(PEG)-6000和KCl存在下,IgG与AgGIgG发生免疫反应,裸露的银纳米颗粒在KCl和PEG-6000的作用下发生了聚集,导致体系在485 nm处的共振散射峰增强。考察了pH值、AgGIgG、PEG和KCl浓度,温育温度和时间及共存物质的影响。在最佳条件下,IgG浓度c_IgG在4.0～480 ng·mL-1范围内与485 nm处的共振散射光强度增加值ΔI_{485 nm}呈线性关系,回归方程为ΔI_{485 nm}=76.8c_IgG+4.7,方法检出限为2.4 ng·mL-1 IgG 。该法用于定量分析血清IgG,简便快速,本法结果与免疫比浊法结果一致。     

基于核酸适配体修饰的纳米金双与门逻辑开关检测牛奶中的三聚氰胺和环丙氨嗪

通过使用适配体、十六烷基三甲基溴化铵(CTAB)、三聚氰胺和环丙氨嗪控制金纳米粒子的聚集和分散,设计了简单的双与门逻辑开关用来检测牛奶中的三聚氰胺和环丙氨嗪。首先,基于适配体T31与三聚氰胺的强特异性,通过CTAB的加入控制纳米金的聚集,制作了一个与门逻辑开关(AND logic gate 1)检测是否存在三聚氰胺。此逻辑开关用肉眼可识别的三聚氰胺检出限为0.24 mg·L^-1,借助分光光度计的检出限(LOD)为85μg·L^-1。根据适配体Tcy1与环丙氨嗪的强特异性,通过CTAB的加入控制纳米金的聚集,设计了与门逻辑开关(AND logic gate 2)。此逻辑开关用肉眼可识别的检出限为0.17 mg·L^-1,借助分光光度计的检出限(LOD)为9.0μg·L^-1。因此,通过这一逻辑开关组可以实现牛奶中三聚氰胺和环丙氨嗪的快速检测。     

Broad spectral photonic crystal fiber surface enhanced Raman scattering probe

A broad spectral surface enhanced Raman scattering sensor is developed using the solid core holey photonic crystal fiber with silver nanoparticles cluster. This SERS probe offers an operational excitation wavelength range overlaying visible light and near infrared light. The PCF SERS sensing is demonstrated in the detection of the 4-Mercaptobenzoic acid (10⁻⁶ M) solution with 514.5 and 785 nm excitation. In this structure of PCF sensor, the related analysis shows that leakage modes also make an important contribution in the SERS activity not only by the evanescent field way.     

Momentum-space optical model for K+-nucleus scattering

The momentum-space optical model of K⁺-nucleus scattering is analyzed and comparison with other conventional models is shown. The model is based on the multiple scattering formalism in which the optimal factorization approximation is used. Off-energy-shell extension of the elementary K⁺-nucleon amplitude is neglected which reduces non localities in the optical potential. Predictions of the model are sensitive to the definition of the K⁺-nucleon energy (energy shifts) but they are independent (1–2%) of a particular form of the covariant K⁺-nucleus scattering equation (relativistic Lippmann-Schwinger, Gross, Erkelenz-Holinde). The Coulomb distortion in the total cross section is important for²⁸Si and⁴⁰Ca at low momenta (≈10%). Off-energy-shell effects in the optical potential are discussed too. Results for the total and reaction cross sections are systematically below the data. The reaction cross sections are in a larger disagreement with the data than the total cross sections. This work was supported by grants ASCR A1048703 (P. Bydžovsky) and GACR 202/96/1566 (M. Sotona).     

Measurement of electric field by interferometric spectral trace observation

We present a new methodology that obtains, in an analytical way, the complex electric field of ultrashort pulses. This methodology is based only on Fourier analysis of the frequency components of spectrally resolved interferometric collinear autocorrelations. We present an experimental demonstration of this technique and the results are compared with the conventional second-harmonic generation frequency-resolved optical gating technique.     

Resonance scattering and singularities of the scattering function

Recent studies of transport phenomena with complex potentials are explained by generic square root singularities of spectrum and eigenfunctions of non-Hermitian Hamiltonians. Using a two channel problem we demonstrate that such singularities produce a significant effect upon the pole behaviour of the scattering matrix, and more significantly upon the associated residues. This mechanism explains why by proper choice of the system parameters the resonance cross section is increased drastically in one channel and suppressed in the other channel.     

各向同性光纤探头的制作及介质中散射光的探测

利用高散射性球和光纤制成了各向同性的光纤探头,对该探头接收不同方向入射光的特性测试表明,在10°~350°之间散射球输出信号相对变化率小于10%.用所制作的光纤探头探测散射介质中的相对能流率分布所得的实验结果与理论结果相符合.     

Elastic and inelastic scattering of K+ mesons on deformed nuclei

Various aspects of the scattering of medium energy K⁺ mesons on deformed nuclei are investigated in the light of a specific example, viz. the scattering of 800 MeV/c positive kaons on ¹⁵²Sm. The effects of coupled channels are found to be significant despite the fact that the K⁺ meson is a rather weakly interacting hadronic probe. The localization of the reaction mechanism on a deformed target is discussed for both protons and K⁺ mesons to compare the extent of surface and volume probing capability of these two projectiles. The results show the remarkable sensitivity of the elastic and inelastic K⁺ differential cross sections to the differences between the neutron and proton density distributions in deformed nuclei.