基于光波导光模光谱的固液界面受体配体反应动力学研究

为了探讨血管内皮细胞生长因子和其受体作用的动力学特征,在3-氨基3-乙氧基硅烷修饰的光波导传感器芯片表面通过戊二醛将血管内皮细胞生长因子固定,用光波导光模光谱法对溶液中的血管内皮细胞生长因子受体与固定化血管内皮细胞生长因子作用的反应动力学进行了研究。通过对不同浓度的受体分子的在线结合、解离的光波导光模光谱数据的分析,拟合出相应的结合、解离反应速率常数分别为6.86×105L.(mol.s)-1和1.15×10-3s-1。结果表明,非标记的光波导光模光谱法适用于高效、准确的受体配体作用反应动力学特征测量,所建立的基于光波导光模光谱技术的体外研究模型,是相关药物的开发和作用机理研究的方便快捷的平台。     

空芯光波导在光谱气敏检测中的应用

空芯光波导(HWG)用于光谱气体检测中,既可以实现光路的传输,又可以充当气体样品池实现长光程高灵敏度测量,具有体积小,响应时间快、成本低、光路稳定灵活等优点。介绍了基于镀银/碘化银的空芯光波导(Ag/AgI-HWG)、光子带隙空芯光波导(PBG-HWG)和基片集成空芯光波导(iHWG)等类型的空芯光波导,并总结了近年来空芯光波导在光谱气敏检测中的研究及进展,梳理了其应用方式及应用领域。研究表明,空芯光波导替代传统的气体池与傅里叶变换红外光谱(FTIR)、激光吸收光谱和拉曼光谱等不同的光谱技术结合已取得一系列成果,且已经应用于环境监测、呼气诊断和工业过程检测和控制等领域。其中,基于中红外激光吸收光谱的空芯光波导传感器组成相对简单,成本较低,与各类光波导的兼容性和环境适应性较强,发展前景较好。总之,随着激光技术、光波导技术和光谱技术的发展,基于空芯光波导的光谱气体检测正在迅速发展,并逐步由实验室走向现场应用。     

新型含芘荧光探针分子与蛋白质相互作用的光谱研究

利用荧光发射光谱和紫外-可见吸收光谱,研究了新型含芘荧光探针分子芘丁酰谷氨酸(PLE)和芘甲酰谷氨酸(PYE)与溶菌酶(Lyso)和牛血清白蛋白(BSA)的相互作用,分析了结合过程和机理。结果显示:不同间隔链长度的探针分子在与Lyso作用时,表现的光谱性质差别不大,这主要是由于探针分子结合到了Lyso的表面;而不同间隔链长度的探针分子在与BSA作用过程中,却表现不同的光物理性质,这可能是探针分子作用于BSA空腔时其结合位点或者结合方式的不同引起的。目前的研究对揭示蛋白质分子的识别位点和定位切割具有重要的意义。     

掺锡As2S8薄膜光折变效应及其在条波导制备中的应用研究

实验研究了Sn₁As₂₀S₇₉非晶态半导体薄膜的光折变效应及其膜厚变化的现象,归纳了沉积态样品、退火态样品和光饱和态样品的实验规律,提出和采用紫外光激励的方法试制了Sn₁As₂₀S₇₉条形波导,632.8 nm波长导模激励显示该波导具有良好的导波特性. 关键词： 光波导技术 硫属化合物玻璃 光阻断效应 光折变效应     

掺杂As2S8非晶态薄膜波导的光阻断效应

实验研究了未掺杂和低浓度掺锡和掺磷的As₂S₈薄膜波导的光阻断效应,提供了三种样品的光阻断响应曲线、室温退激实验数据和光谱测试数据. 结果表明,掺锡样品可以明显提升毫秒级响应的快过程恢复作用,同时还具有减少残留传输损耗的效果,掺磷的效果则相反. 结合实验结果给出了分析讨论. 关键词： 光波导技术 硫属化合物玻璃 光阻断效应 掺杂     

光谱及分子探针方法研究番茄Metacaspase蛋白与Ca~(2+)的相互作用

Metacaspases(MCPs)是发现于植物、真菌、原生动物体内的一种结构上类似多细胞动物Caspase的半胱氨酸蛋白酶家族,其大多数成员的激活依赖于钙离子,但钙离子如何影响MCPs的激活机制有待深入研究。借助圆二色谱技术、Terbium/Stains-all探针技术以及荧光光谱技术,以番茄Ⅱ型Metacaspase(LeMCA1)重要位点突变的三种体外原核表达重组蛋白,包括LeMCA1C139A(活性催化位点突变体)、LeMCA1K223G(自降解位点突变体)以及预测的Ca2+结合位点突变体LeMCA1D116A/D117A为研究材料,探究了MCPs与Ca2+相互作用机制。实验结果表明,Ca2+与LeMCA1之间既不存在强烈的结合作用,也不影响蛋白的二级结构,但Ca2+通过相互作用改变LeMCA1的三级结构来实现对LeMCA1的酶原激活过程。其中,LeMCA1蛋白的Asp-116,Asp-117氨基酸残基作为预测的与Ca2+作用的重要位点,其缺失将导致蛋白与Ca2+相互作用能力下降。利用圆二色谱、荧光光谱结合离子探针技术研究了典型茄科植物番茄中Ca2+与LeMCA1的相互作用特性,结合之前同源序列比对、位点突变结果确定了LeMCA1中的Asp-116,Asp-117氨基酸残基影响着Ca2+与蛋白质的相互作用。该结果对后续LeMCA1的生化特性及晶体结构的解析研究有着重要的参考价值。     

掺锡As2S8薄膜光折变效应及其在条波导制备中的应用研究

实验研究了Sn1As20S79非晶态半导体薄膜的光折变效应及其膜厚变化的现象,归纳了沉积态样品、退火态样品和光饱和态样品的实验规律,提出和采用紫外光激励的方法试制了Sn1As20S79条形波导,632.8 nm波长导模激励显示该波导具有良好的导波特性.     

铜薄膜等离子改性及表面增强拉曼光谱的研究

表面增强拉曼光谱(surface-enhanced Raman spectroscopy, SERS)技术是一种基于探测吸附于金属基底表面分子振动光谱的快速无损检测方法,目前广泛应用于表面吸附、电化学催化、传感器、生物医学检测和痕量的检测与分析等领域。本实验采用直流磁控溅射技术在BK7玻璃基底上沉积一层厚度为50 nm的金属铜薄膜,在Ar离子轰击作用下获得不同表面粗糙度的金属铜薄膜样品,从而制备具有不同表面增强拉曼光谱活性的金属基底。实验样品分别通过X射线衍射仪（XRD）、原子力显微镜（AFM）、分光光度计、拉曼光谱仪表征其结构、表面形貌及光学性质。测试结果表明铜膜在Ar离子束轰击前后,样品X射线衍射谱的峰值强度没有发生变化,说明其晶相结构未发生改变;随着离子束能量的增加,薄膜表面粗糙度改变,光学散射强度随着表面粗糙度的增加而增强;离子束薄膜表面改性后,以罗丹明B(Rh B)为探针分子,表征薄膜样品表面增强拉曼的活性,通过对比不同样品表面Rh B的拉曼光谱,发现其光谱强度随金属铜薄膜样品表面粗糙度的增加而增强。     

光声信号的双谱分析方法研究

基于光声效应的光声光谱技术是光学与声学的有机结合, 可利用不同波长的入射光波, 产生不同的光声信号, 从而为组分识别、组织无损检测等提供高对比度图像, 是一种极具潜力的新型医学诊断技术.但光声光谱检测技术由于受检测方法的制约, 往往扫描时间较长, 而且信号的稳定性和图像识别的准确性也较差. 为了弥补单一光声光谱分析的局限性, 根据光声效应原理和振动理论, 提出了一种光声光谱与光声频谱相结合的双谱分析方法. 该方法通过光声频域信息的定量分析, 可以有效地提高不同组织的光声图像对比度, 从而提高光声成像的组分识别能力, 为光声频谱功能成像奠定理论基础. 实验结果显示, 光声光谱与光声频谱相结合的双谱分析方法可以较好地识别实验组织样品, 可实现高速、高分辨率的组分识别、组织探伤等, 具有广泛的应用前景和重要的临床诊断意义. 关键词： 光声成像 光声光谱分析 光声频谱分析     

毛细管电泳-原子光(质)谱联用技术在金属形态与生物分子相互作用研究中的应用

金属形态与生物分子相互作用研究对于揭示金属元素在正常生命过程、重大疾病的发生、诊断和治疗过程中的作用机理具有重要意义,发展研究金属元素形态与生物活性分子相互作用的新技术和新方法非常重要。简要总结了十余年来,在发展毛细管电泳与电热原子吸收光谱和毛细管电泳与电感耦合等离子体质谱在线联用新技术,及其在不同形态金属与生物分子相互作用机理研究方面的工作。这些工作利用毛细管电泳-原子光(质)谱联用技术不仅能够直接证明镉、锌、不同形态的汞、不同形态的锑与谷胱甘肽、DNA、人血清白蛋白、牛血清白蛋白间的相互作用,以及这些金属及其不同形态与生物分子加合物的生成,而且还能够测定相互作用的热力学参数、反应级数和动力学参数。另外,结合圆二色光谱、红外光谱光谱、拉曼光谱和X射线光电子能谱等实验手段,进一步研究了金属及其不同形态与生物分子作用对生物分子二级结构的影响及在生物分子上可能的结合位点等。     

Particle speciation during PEG–Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> hybrid nanoparticle self-assembly on Si(Ti)O<Subscript>2</Subscript>

The kinetics of assembly of polyethylene glycol (PEG)-coated superparamagnetic Fe₃O₄ nanoparticles in aqueous suspension on planar Si(Ti)O₂ surfaces have been determined using high-resolution optical waveguide lightmode spectroscopy (OWLS). Analysis of the results revealed that the initially uniform population was spontaneously transformed into two types of particles with significantly different adsorption behaviour.     

Effect of patterns and inhomogeneities on the surface of waveguides used for optical waveguide lightmode spectroscopy applications

It has been found that patterns and inhomogeneities on the surface of the waveguide used for optical waveguide lightmode spectroscopy applications can produce broadening and fine structure in the incoupled light peak spectra. During cell spreading on the waveguide, a broadening of the incoupling peaks is observed, while regular microstructures on the incoupling grating produce shifts and splitting of the peaks. A theoretical model, based on the zigzag wave representation of light propagation in a planar optical waveguide has been developed in order to understand the physical background of the observed effects. Numerical results are given for the different cases observed, and they are compared with the experimental data. Several possible applications of these effects are considered. Received: 10 July 2000 / Revised version: 9 October 2000 / Published online: 21 February 2001     

光谱法研究FCLA与人血清白蛋白的相互作用

在生物学和医学中活性氧的检测非常重要。海萤荧光素类似物FCLA是检测单态氧(1O₂)和超氧阴离子(O-₂)的一种高灵敏的化学发光探针。文章用光谱法研究了FCLA与人血清白蛋白(HSA)的结合反应,发现FCLA对HSA的荧光有很强的猝灭作用。从荧光猝灭结果求得了FCLA与HSA的结合位点数。根据Frster非辐射能量转移机理探讨了二者相互结合时其给体-受体间的距离和能量转移效率, 从而证实了它们的结合作用为静态猝灭过程。阐明了由于能量转移所导致的HSA荧光的猝灭及FCLA荧光的产生机理。通过光谱法对FCLA与HSA的相互作用的研究,阐明FCLA的运输过程及其在体内的作用机制,对实现利用探针在体检测活性氧具有一定的意义,同时也为药物动力分析、体内药物转运的研究提供了基础。     

Parallel detection and quantitative analysis of specific binding of proteins by oblique-incidence reflectivity difference technique in label-free format

In this work, we parallelly detected the specific binding between microarray targets including 12 different kinds of proteins and the probe solution containing five corresponding antibodies and quantitatively analyzed the interactions between CDH13 and solution phase anti-CDH13 at six different probe concentrations by oblique-incidence reflectivity difference (OIRD) method in label-free format. The detection sensitivity reached 10 ng/mL. The experimental results indicate that the OIRD method is a promising and competing technique not only in research work but also in clinic.     

Fabrication and study of a metal-clad planar waveguide based biosensor

A metal-clad planar optical waveguide biosensor having five layer structure has been fabricated to study the detection of Pseudomonas and Pseudomonas-like bacteria. This waveguide is designed to increase the overlap of the evanescent field extension from the sensor face with the micro-scale biological objects in the bulk solution, to place most of the entire volume of the bacteria within the evanescent field. The results presented here leads to a significant optimization of the important design parameters to sense micro-scale biological objects. We have compared our computed results with the results obtained by similar non-metallic clad biosensor. The effect of affinity-layer refractive index on the sensitivity of these planar waveguides is also studied. We have shown this for some special cases by obtaining reflection dips at the particular angle of incidence. Our observations show that the metal-clad planar optical waveguide biosensor having higher affinity refractive index will give better sensitivity than other similar non-metallic clad biosensor. The validation of metal-clad planar optical waveguide sensor for the detection of Pseudomonas aeruginosa bacterium is also made.     

Sequence Dependent Ultrafast Electron Transfer of Nile Blue in Oligonucleotides

In this contribution we report studies on the nature of binding of nile blue (NB), a well known DNA intercalating drug, with three synthetic DNA oligonucleotides, (CGCAAATTTGCG)₂, (GCGCGCGCGCGC)₂ and (ATATATATATAT)₂. The nature of fluorescence quenching of the ligand upon complexation with the DNAs has been studied using steady state and picosecond-resolved optical spectroscopic techniques. The geometrical restriction on the probe in the DNA microenvironment is measured using picosecond-resolved rotational anisotropy measurements. Our experiments identify both non-specific electrostatic and intercalative modes of interaction of the probe with the DNAs at lower and higher DNA concentrations, respectively. This dual nature of binding is also confirmed through gel electrophoresis experiments. The nature of electron transfer (ET) reaction of GC base pairs with intercalated NB has also been explored. Competitive binding study reveals that binding affinity of the probe is higher with SDS micelles than with the DNAs within its structural integrity in presence of the micelles, as evidenced from circular dichroism (CD) measurements. The complex rigidity of NB with various DNAs and its fluorescence quenching with DNAs elucidate a strong recognition mechanism between NB and DNA.     

微槽式光学谐振腔超声传感效应验证*

摘 要：光学微腔的高灵敏度主要源于其结构在时间和空间上对光场的局域增强作用和频率选择作用。其结构在垂直于波导方向上形成了高反射的边界,形成了一种回声腔,使得光在波导内来回反射,从而增强了波导内部的光场强度。当外界存在微小的压力波动时,它将引起波导内部的介电常数和压力场的变化,从而改变了谐振腔内的模式场分布和传输特性,据此可以实现对微小的压力波动进行高灵敏度检测。本文设计了一种高品质因子（Q）的光波导微槽式环形谐振腔超声传感器,完成器件制备并搭建了测试系统,依据倏逝波效应实现了超声探测。测试结果表明,该传感器的品质因子为1.38×107,在800 kHz ~1 MHz范围内响应平坦,在900 kHz的信噪比可以达到27 dB,灵敏度达到 -168 dB。本文设计的传感器可以为水声探测等领域的研究提供关键技术支持。     

All optical switching in azo-polymer planar waveguide

In this paper all optical switching in planar methyl red doped poly (methyl methacrylate) (MR/PMMA) waveguide and the effects of different parameters on this process are presented. Switching was achieved by a 488 nm Ar ion laser (pump beam) on a 633 nm He-Ne laser (probe beam) when passed through the waveguide. The effect of temperature and pump intensity, polarization and chopping frequency on switching is investigated. The switching process is attributed to trans-cis-trans photoisomerization of azo dyes in the polymer host. By studying the absorption spectrum of the sample, it is shown that both pump and probe laser beams are effective on the switching process.     

The study of electro-optical sensor based on slotted photonic crystal waveguide

A compact and sensitive electro-optical sensor based on slotted photonic crystal waveguide (S-PhCW) is demonstrated. The electro-optical sensor can be realized in photonic crystal (PhC) slabs of silicon in Silicon-on-Insulator (SOI). Nonlinear optical polymer is used as infiltration. By applying three-dimensional finite difference time domain (3D-FDTD), the sensitivity and quality factor of electro-optical sensor with different slotted waveguide width are calculated. In addition, sensitivity and the optical properties such as transmission spectrum and field distributions are compared between electro-optical sensor based on line defect photonic crystal waveguide (W1-PhCW) and that based on slotted photonic crystal waveguide (S-PhCW). Simulation results demonstrate that, compared with electro-optical sensor based on line defect photonic crystal waveguide, the sensitivity and quality factor is improved by 30 times and 6.6 times respectively in sensor based on slotted photonic crystal waveguide. Besides, the proposed PhC sensor devices have the advantage of a compact structure with the potential for monolithic integration with optical-to-electrical on-chip conversion and detection.