新型动态光镊技术及应用研究

发布时间：2018-08-02 19:15

【摘要】：光镊技术在科学前沿领域具有越来越重要的应用价值。光镊通过光场形成的三维势阱直接捕获微小颗粒,具有无标记、非接触、无损伤、实时检测等特点,并且具有皮牛量级的微小作用力测量及微米量级的精确定位能力,因而非常适用于生物样品的操控。激光光镊的出现为生物医学领域中细胞及生物分子的研究带来了前所未有的操纵手段。然而,传统的激光光镊技术是针对远场的捕获,且并不是对所有微小颗粒都能实现完美的操控。针对激光光镊的局限性,近年来结构型表面等离激元光镊技术等近场光镊技术得到了快速发展,但仍然存在场强度偏弱、难以实现动态操控等缺点。首先,针对激光光镊技术在生命医学领域的应用,本论文提出了一种新型动态激光光镊技术,并针对具体的生物学应用开展了相关工作。其次,针对目前光镊技术存在的缺陷,本论文提出了基于全光调控的聚焦型动态表面等离激元光镊技术,实现了针对金属颗粒的灵活动态操控,并进一步针对其应用前景进行了探索性研究。本论文的主要内容包括:1.针对不同材料的颗粒在激光和表面等离激元光场中的受力情况进行了理论分析,为光镊技术的进一步应用奠定了理论基础。2.针对生物医学领域中药物筛选、细胞检测及分选等热点问题,提出了一种新型动态光镊系统。通过测量捕获颗粒在液体中运动的临界速度,进一步开展了针对药物粘滞系数、转基因细胞、癌细胞鉴别等方面的相关研究。该系统实现了快速、无标记、低耗量、高精度的检测,为进一步针对临床应用的推广奠定了基础。3.针对目前光镊技术中倏逝场偏弱、金属颗粒难以捕获的问题,提出了基于全光调控的聚焦型动态表面等离激元光镊技术。理论上分析了聚焦表面等离激元场对金属颗粒及纳米线的作用力,并与激光光镊中的受力做了对比分析;在实验上通过紧聚焦径向偏振光激发表面等离激元场对其实现了对金属颗粒的稳定捕获和动态操控;并进一步针对金属纳米线结构的特殊性,通过调控紧聚焦的线偏振光的偏振方向,实现了对金属纳米线的定位和定向操控。4.针对聚焦型表面等离激元光镊的问题,提出并搭建了双SPPs光镊系统,实现了严格意义上的单金属颗粒稳定捕获和动态操控。在此基础上,基于表面等离激元光镊中金属膜和金属颗粒之间产生的极大局域增强场,进一步开展了表面增强拉曼散射光谱的测量方面的研究,实现了对分子拉曼信号的增强及测量。5.针对SPPs光镊技术在生物学的应用,实现了透过细胞膜的金属纳米颗粒操控,为进一步针对细胞膜成分检测方面的研究提供了新的技术支持。
[Abstract]:Optical tweezers technology has more and more important application value in the front field of science. Optical tweezers capture tiny particles directly through three-dimensional potential wells formed by optical fields, which have the characteristics of no marking, no contact, no damage, real time detection, etc., and have the ability of measuring the micro force in the order of skin cattle and accurate positioning in the order of micron. Therefore, it is very suitable for the manipulation of biological samples. The emergence of laser optical tweezers has brought unprecedented manipulation for the study of cells and biomolecules in biomedical field. However, traditional laser tweezers are aimed at far field trapping, and not all tiny particles can be manipulated perfectly. In view of the limitations of laser optical tweezers, near-field optical tweezers, such as structural surface iso-excited optical tweezers, have been developed rapidly in recent years, but there are still some shortcomings such as weak field intensity and difficulty in dynamic manipulation. Firstly, aiming at the application of laser optical tweezers in the field of life medicine, a new dynamic laser optical tweezers technology is proposed in this paper, and related work is carried out for specific biological applications. Secondly, aiming at the defects of optical tweezers technology, this paper proposes a focused dynamic surface isobaric optical tweezers technology based on all-optical regulation, which realizes the flexible and dynamic manipulation of metal particles. Furthermore, an exploratory study on its application prospect is carried out. The main contents of this thesis include: 1. The stress of particles of different materials in laser and surface isobaric light fields is analyzed theoretically, which lays a theoretical foundation for the further application of optical tweezers. A new dynamic optical tweezers system is proposed to solve the hot issues in biomedical field such as drug screening, cell detection and sorting. By measuring the critical velocity of trapping particles in liquid, further studies were carried out on drug viscosity coefficient, transgenic cells, cancer cell identification and so on. The system realizes fast, unmarked, low consumption and high precision detection, which lays a foundation for further popularizing clinical application. Aiming at the problem that evanescent field is weak and metal particles are difficult to capture in optical tweezers a focused dynamic surface isobaric optical tweezers based on all-optical regulation is proposed. The forces acting on metal particles and nanowires in the focusing surface are analyzed theoretically and compared with the forces in laser optical tweezers. In experiments, the stable capture and dynamic manipulation of metal particles are realized by means of the surface excited by tightly focused radial polarized light, and the particularity of metal nanowire structure is further considered. By adjusting the polarization direction of the tightly focused linear polarized light, the orientation and control of metal nanowires are realized. In order to solve the problem of focusing surface isobaric optical tweezers, a dual SPPs optical tweezers system is proposed and constructed, which realizes the stable capture and dynamic manipulation of single metal particles in strict sense. On this basis, the measurement of surface-enhanced Raman scattering spectra is further studied on the basis of the maximum local enhancement field between the metal film and the metal particles in the surface isobaric optical tweezers. The enhancement and measurement of molecular Raman signal are realized. In view of the application of SPPs optical tweezers in biology, metal nanoparticles manipulating through cell membrane are realized, which provides a new technical support for further research on the detection of cell membrane composition.
【学位授予单位】：南开大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TN24

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