激光热透镜光谱分析法*

激光热透镜光谱法是20世纪80年代发展起来的一种光热光谱分析技术。该法以其高灵敏度、低检出限以及适应于微、少量样品分析等特点引 分析工作者的极大兴趣。本文从测量装置、理论、痕量无机物和有机物测定以及与其它分析技术的联用等方面对1990年以来激光热透镜光谱分析法的进展作了较为详细的综述。     

Lipid Biomarkers of Lens Aging

Lipids are important structural components of cell membranes and have profound effect on membrane fluidity. Lipid profiling and lipidomics have captured increased attention due to the well-recognized roles of lipids in numerous human diseases. Investigating lipid profiles not only provides insights into the specific roles of lipid molecular species in health and diseases, but can also help in identifying potential preventive or therapeutic biomarkers. Cataract, the loss of transparency of eye lens, is a disease of protein aggregation. There are several factors contributing to the stability in protein conformation. Age-related changes in lipid composition could be a contributing factor for altered protein–lipid interaction leading to protein aggregation and cataract. Keeping this in view, in the present study, fatty acid profiling from different age groups of lenses was carried out, using a freshwater catfish as the model. Total lipids were extracted from lenses of three different age groups of fishes (young, adult, and aged) and fatty acid methyl esters (FAME) were prepared and FAME analysis was carried out using gas chromatography–mass spectrometry. The results showed that three fatty acids viz. heneicosylic acid (C21), docosahexaenoic acid (C22:6), nervonic acid (C24:1) which were not present in the adult lens, appeared in the aged lens. On the other hand, eicosenoic acid (C20:1) present in the adult lens was found to be absent in the aged lens. The appearance or disappearance of these fatty acids can possibly serve as biomarkers of aging lens which is the most vulnerable stage for cataract development.     

交叉束激光热透镜光度法的研究

激光热透镜光度法是一种高灵敏度光谱分析技术。本文用探测束非聚焦的He-Ne激光双光束交叉热透镜技术研究了影响热透镜灵敏度的几个因素,并对远场光斑截面内信号强度分布进行了测定,对实验结果进行了讨论。在正交束构型的最佳参数下,检测了1-(2-吡啶偶氮)-2-萘酚(PAN)-Co(Ⅲ)的氯仿溶液,得到最小吸光度为1.17×10~(-6),相当于1.7 ng/mL的     

Two-Laser Thermal Lens Spectrometry with Signal Back-Synchronization

A two-laser dual-beam thermal lens spectrometer based on continuous-wave lasers, which implements the mode with signal back-synchronization, is developed with the aim to develop instrumentation for thermal lens spectrometry. This mode offers a potentially higher sensitivity of measurements in comparison with the lock-in mode of thermal lens measurements and variation of conditions depending on the measurement medium (solvent, or dispersed system, or solids). The wider possibilities of the back-synchronization mode in thermal lens spectrometry both for solving problems of chemical analysis and in some related fields are shown.     

固相萃取-反相高效液相色谱法测定隐形眼镜护理液中聚胺丙基双胍

建立了固相萃取-反相高效液相色谱法测定隐形眼镜护理液中聚胺丙基双胍的方法.用Spe-ed WCX固相萃取柱(500 rag/3 mL)将样品浓缩富集后,以Shiseido C18色谱柱(150 min×4.6 mm,5 pm)为分离柱,以pH 4.0的乙腈-20 mm01.L-1乙酸铵(体积比16比84)为流动相,检测波长为235 nm,7 min内测定样品中聚胺丙基双胍.方法检出限(S/N=3)为0.046 mg·L-1,相对标准偏差为3.3%(n=7),线性范围为100～800 mg·L-1,加标回收率93.5%～110.9%.     

C60的热透镜光谱解析

由于测定方法的不同,对C₆₀的三线态本征寿命的数值一直存在争议.室温下C₆₀的荧光和磷光较弱,利用时间分辨热透镜技术测量C₆₀的三线态本征寿命具有以下优点:不需要其它参比样品;信号对热灵敏,因而适用于稀溶液.     

基于自由曲面的LED准直透镜设计

本文基于准直光束照明的自由曲面透镜设计方法,设计了一种以单颗LED为光源的准直透镜,其可应用于投影仪的照明系统。根据几何光学原理构造自由曲面,该方法无需求解复杂的偏微分方程,计算简单。准直透镜由内自由曲面折射面、球面、抛物面全反射曲面以及平面组成,利用Matlab编程求出自由曲面轮廓曲线的离散数据点,导入Solidworks中进行曲线拟合,建立透镜的实体模型。为探讨LED光源尺寸对准直透镜光斑影像的影响,在Tracepro中对透镜进行非序列光线追迹,模拟结果表明:当光源半径不大于1 mm时,其光学效率达到86.26%以上,视场半角达到3.3度以内。     

Raman Spectroscopy of Galactosemic Rat Lens Crystalline: Correlation of Microscopic Changes of Lens Proteins at Molecular Levels with Gross Cataractous Alteration

Near‐Infrared Fourier trans form (near‐IR FT) Raman spectros copy has been used to study the structural changes of lens proteins both in cortex and nucleus of galactosemic rat lenses. It was found that tyrosine doublet ratio of Raman bands, I₈₃₂/I₈₅₅, in creased more rapidly in the cortex than in the nucleus during a 5‐week period of galactose feeding, i.e., from 0.86 to 1.1 for the cortex and 0.88 to 0.92 for the nucleus. The ratio obtained for lens nucleus suggests that a lower ratio of less than 1 does not necessarily reflect the apparent transparent state of lens morphology. More over our results for the in crease of tyrosine doubletratio with the extent of cataract formation in galactosemic lens appear to indicate that there is more hydration in crystallins of the cortex than the nucleus since the in creased ratio of tyro sine doublet has been shown to be due to the hydrogen‐bond formation of hydroxyl groups in various tyrosines of proteins with water. The tryptophan band ratio at 880 cm^?1 and 757 cm^? (I₈₈₀/I₇₅₇) under went a precipitous de crease in the cortex and a rather gradual de crease in the nucleus, suggesting buried tryptophan residues become more exposed in the cortex than in the nucleus during galactose‐induced cataractogenesis. Based on the changes of the two ratios, I₈₃₂/I₈₅₅ and I₈₈₀/I₇₅₇, the change of lens protein environment induced by galactosemic feeding appeared to take place in the cortex first, which was consistent with the observation that the development of an opaque lens be gins in the cortex. While no sulfhydryl (‐SH) signal was detected, there was a slow in crease of disulfide (‐S‐S‐) signal in the cortex of galactose‐fed lenses as compared to control lenses with out galactose. This suggested that a loss of lens glutathione occurred early and oxidation of cysteines in crystallins started in the first week, i.e., be fore the onset of cortical cataract. In contrast, for nucleus of galactosemic lenses the signal of the‐SH group was detected and yet the ‐S‐S‐signal of crystallins could not be found. In this study, we have conclusively demonstrated using Raman vibrational band shift that galactosemic cataract be gins in the cortex, and that the lens cortex suffers more structural alteration in crystallins than the nucleus.     

靶向人晶状体上皮细胞免疫毫微球的制备

采用偶联法使抗人晶状体上皮细胞单克隆抗体与聚乳酸载 5_氟尿嘧啶毫微球偶联 ,制备出靶向人晶状体上皮细胞的免疫毫微球。采用扫描电镜和透射电镜观察微球形貌和结构 ,用动态光散射粒径分析仪测载药毫微球粒径。ELISA法检测偶联后的抗体活性 ,间接免疫荧光法检测该免疫毫微球与晶状体上皮细胞的特异性结合能力。结果显示载药毫微球表面光滑 ,平均粒径为191 0± 0 2 0 2nm ,其载药率为 8 2 %。免疫载药毫微球中的单克隆抗体HILE6保留达到原免疫活性84 %。该免疫载药毫微球能与晶状体上皮细胞特异性结合。该实验为特异性抑制晶状体上皮细胞增殖 ,预防白内障术后并发症_后囊混浊提供了重要的科学依据     

强脉冲激光激发的热透镜光度分析法

用自装的热透镜测量装置,观察了强脉冲激光作用下的热透镜行为。测量丙酮/水混合液中的Cocl₂,检测限为3×10^-7M,相当于6×10^-6的吸光度。将差分放大技术用于热透镜测量,降低了He-Ne激光振幅噪声的影响,改善了信噪比。     

Determination of Cationic Surfactant by Laser Thermal Lens Spectrometry

A novel method for the determination of cationic surfactant by laser thermal lens spectrometry was developcd,It was based on reaction between 1-hydroxy-2-(5-nitro-2-Pyri-dylazo)-8-aminonaphthaenc-3,6-disulfonic acid (5-NO2-PAH) and cationic surfactant to form 1:2 ionic association complex in a weakly basic medium (pH 9.44),The determination conditions and the mechanism were discussed,The method has been appliced to the analysis of wastewater and moat water samples.     

Hydrogel Nanocomposite as a Synthetic Intra-Ocular Lens Capable of Accommodation

A hydrogel nanocomposite was designed, synthesized, and evaluated for use as an auto-focusing intra-ocular lens. The hydrogel scaffold was composed of a monomer-free, thiol that contained polyacrylamide (5%), which was allowed to gel in the presence of nanoparticles at pH 7.4, 25°C. The nanoparticles consisted of a proteo-mimetic polyacrylamide nanogel (∼42 nm), bovine serum albumin (BSA) (∼6 nm), and hydrophilized silica (∼3 nm). The extent of nanoparticle loading increased with decreasing particle size. The elastic modulus increased with increasing loading of the proteo-mimetic nanogels and BSA, and it decreased with hydrophilized silica. In this investigation, the hydrogel that contained silica was the most promising class of nanocomposite hydrogels with properties comparable to that of a young porcine lens. A nanocomposite that consisted of 10% hydrogel scaffold and 24% hydrophilized silica (elastic [E] modulus of ∼1.0 kPa and refractive index [RI] of 1.42) was injected into a pre-evacuated porcine lens capsular bag. The composite lens was evaluated in a custom-designed four-arm radial stretcher, and its force-time spectrum was characterized by time constants of 60 ± 8.9 and 800 ± 32 ms. These results were comparable to a young porcine lens (E Modulus of 1.2 kPa; RI of 1.4105; time constants of 48.3 ± 0.58 and 668 ± 24.6 ms, respectively)     

毛细管柱气相色谱法测定角膜接触镜护理液中薄荷脑

角膜接触镜护理液样品以乙酸乙酯超声提取,提取液经离心后供气相色谱测定。采用DB-Wax毛细管柱(30m×0.32mm,0.5μm)分离样品,氢火焰离子化检测器检测,内标法定量。薄荷脑线性范围为3.74～187.2mg.L-1,方法的检出限(3S/N)为0.15mg.L-1。方法用于护理液中薄荷脑的测定,回收率在98.3%～99.3%之间;相对标准偏差(n=6)在0.72%～1.95%之间。     

表面活性剂及水溶性高分子对激光热透镜信号的增强作用

研究了不同浓度的表面活性剂和水溶性高分子在水相或有要相中对激光热透镜信号的增强作用,探讨了其增强机理,表明随表面活性剂,水溶性高分子浓度的变化,溶剂介质微环境物理特性参数发生变化,从而引起热透镜信号的增强。     

Lens epithelial cell response to polymer stiffness and polymer chemistry

Posterior capsule opacification (PCO) is the most common complication of cataract surgery, and intraocular lens (IOL) implantation is the standard of care for cataract patients. Induction of postoperative epithelial-mesenchymal transition (EMT) in residual lens epithelial cells (LEC) is the main mechanism by which PCO forms. Previous studies have shown that IOLs made with different materials have varying incidence of PCO. The aim of this paper was to study the interactions between human (h)LEC and polymer substrates. Polymers and copolymers of 2-hydroxyethyl methacrylate (HEMA) and 3-methacryloxypropyl tris(trimethylsiloxy)silane (TRIS) were synthesized and evaluated due to the clinical use of these materials as ocular biomaterials and implants. The chemical properties of the polymer surfaces were evaluated by contact angle, and polymer stiffness and roughness were measured using atomic force microscopy. In vitro studies showed the effect of polymer mechanical properties on the behavior of hLECs. Stiffer polymers increased α-smooth muscle actin expression and induced cell elongation. Hydrophobic and rough polymer surfaces increased cell attachment. These results demonstrate that attachment of hLECs on different surfaces is affected by surface properties in vitro, and evaluating these properties may be useful for investigating prevention of PCO.     

倾斜交叉差分式激光热透镜光谱法特性研究

本文描述了一个倾斜交叉、差分式激光热透镜光谱法。采用本方法可消除较高的溶剂空白的影响。文章讨论了调制频率和泵浦光功率对热透镜信号的影响,给出了检测Cu~(2+)的工作曲线,讨论了影响方法灵敏度的诸因素,提出了可能的改进方案。     

激光热透镜光度法测定痕量锑

利用He-Ne激光,观测了锑-孔雀绿络合物的激光热透镜效应。其在苯中最低检测浓度为10ng/ml Sb,测定线性浓度范围为1～120ng/ml,测定的相对标准偏差为6.5％。本方法比常规光度法的测定灵敏度高12倍,相当于吸光度3.3×10~(-4)。     

针剂中多巴胺的近场激光热透镜光谱法测定

基于多巴胺与四氯苯醌荷移反应 ,建立了近场激光热透镜光谱法测定多巴胺的新方法 ,讨论了测定条件的影响 ;结果表明 ,该法灵敏度高 ,多巴胺质量浓度在0.04～2mg·L-1 范围内与信号强度呈线性关系 ,检出限20μg·L-1;应用于药物制剂中多巴胺的测定 ,获得了满意的结果