基于图像测定磁性纳米材料磁矩参数的研究

发布时间：2018-01-28 02:29

本文关键词： 磁性纳米颗粒胶体液滴集体磁矩磁场动力学数字图像处理　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来,磁性纳米材料以其磁学性质广泛应用于生物医学研究中,磁性纳米粒子可以作为药物载体,通过外加梯度磁场,将药物输送至肿瘤部位,起到靶向治疗的作用。磁性纳米粒子还可以用于磁热疗,将磁性微粒输送至病灶区域,在外加交变磁场的作用下,磁性微粒产生磁热效应从而杀死病变细胞。磁性纳米粒子还可以用作MRI造影剂,如超顺磁性的氧化铁纳米粒子具有较高的弛豫率和低廉的价格,并且有良好的耐受性、生物相容性及稳定性。了解磁性纳米粒子的磁学性质对其应用具有重要的意义,磁矩是磁性材料最基本的磁学参数,很多磁强计测量原理就是先测出样品的磁矩,再转换为其他参数。测量磁性纳米材料磁矩的磁强计可按照测量样品的尺寸分为三类,在第一章中分别介绍了针对单个磁性纳米颗粒磁矩测量方法：磁力显微镜、洛伦兹显微术；针对微尺度磁性纳米聚集体磁矩测量方法：超导量子干涉仪、巨磁电阻传感器、磁光克尔效应仪：针对大量磁性颗粒聚集体磁矩测量方法：振动样品磁强计、磁天平、电子顺磁共振仪。简述了各个方法的原理及发展现状。本论文主要研究的内容和结果如下：第二章分析了磁矩的测量对于研究磁性材料磁学性质具有重要的意义,而磁性粒子间的相互作用会影响其磁化强度,从而改变其磁矩大小。考虑到磁性纳米颗粒胶体中粒子间的相互作用力,我们提出了一种基于动力学与数字图像处理技术的测量磁性纳米颗粒胶体液滴磁矩的新方法。将微量的水相磁性纳米颗粒胶体(2uL)置于与其密度相同的有机液体中,磁性胶体液滴会在水张力的作用下形成圆球形并悬浮在有机液中。然后外加梯度磁场,胶体液滴会在磁力的作用下沿着磁场增大的方向运动。对胶体液滴水平方向进行受力分析,得到关于液滴速度、加速度、粘滞阻力以及磁力的方程式,即可以通过测量液滴的速度、加速度,得到液滴所受磁力,从而推算出液滴的磁矩。在第二章中,进行了计算机数值模拟实验,证明了此方法的可行性。并且对影响测量的灵敏度的因素进行了分析,得出结论图像采集装置的采集速度越快,磁矩测量的灵敏度越高。第三章中介绍了实验装置,使用Ansoft软件对装置中的“C”型电磁体的磁场分布进行了模拟,并使用特斯拉计测量了外磁场强度,对测量值与距离的关系进行四阶多项式拟合,再对多项式求导得到磁场梯度与距离之间的函数关系。配置与磁性纳米溶液浓度相当的有机液,观察到磁性纳米粒子团形成球形并悬浮于有机相中,外加梯度磁场,液滴在运动的过程中始终保持均匀的球形。所以,我们可以将磁性纳米颗粒胶体液滴看作整体进行分析。第四章和第五章是本文的核心,第四章中测量了不同尺寸的磁性纳米颗粒胶体液滴的磁矩大小,证明了当磁场方向与液滴运动方向相同时,磁性粒子间的磁偶和作用会增强其磁化强度。实验中,分别测量了不同尺寸的γ-Fe2O3与DMSA@Fe2O3磁性纳米胶体液滴的磁矩,两种材料均是由水动力尺寸为82nm y-Fe2O3磁性纳米颗粒胶体制备而成。结果得出水动力尺寸为598nm的γ-Fe2O3磁性纳米胶体液滴总磁矩大于水动力尺寸为83nm的DMSA@Fe203。并且磁热效应强度也与水动力尺寸成正相关。另外,从不同尺寸的Fe3O4磁性纳米胶体液滴磁矩的测量结果中可以看出,水动力尺寸接近的磁性纳米颗粒胶体液滴磁矩大小接近。水动力尺寸较大的液滴在磁场作用下,运动的过程中会出现明显的团聚现象,整个液滴呈固液分离的状态。磁矩明显大于水动力尺寸较小的磁性颗粒液滴。通过测量数据验证了本方法能够定量测量不同水动力尺寸的磁性纳米颗粒胶体液滴的磁矩。在第五章中,我们取浓度分别为6mg/ml, 3mg/ml,1.5mg/ml, 0.75mg/ml的DMSA@Fe2O3磁性纳米胶体,也使用本文提出的新方法测量了这四种浓度胶体液滴的磁矩,同时使用振动样品磁强计与磁天平对材料的饱和磁化强度与磁化率进行了测量。并且测量了这四种材料在5分钟内的磁热升温值,分别计算了磁热效应与本方法所测磁矩、振动样品磁强计所测饱和磁化强度以及磁天平所测磁化率之间的线性相关系数,线性相关性分别为0.986、0.844、0.945。说明本方法所测磁矩可以定量的反映材料的磁热效应。
[Abstract]:In recent years, magnetic nano materials are widely used in biomedical research to the magnetic properties of magnetic nanoparticles can be used as a drug carrier, by applying a gradient magnetic field, the drug delivery to the tumor site, to targeted therapy. Magnetic nanoparticles can also be used for magnetic hyperthermia, magnetic particles transported to the lesion area under alternating magnetic field under the action of magnetic particles of magnetic heat effect to kill the cells. The magnetic nanoparticles can be used as MRI contrast agents, such as superparamagnetic iron oxide magnetic nanoparticles with high relaxation rate and low price, and has good tolerance, biocompatibility and stability. To understand the magnetic properties of magnetic nanoparticles is important the significance of the application of magnetic parameters of magnetic materials, the magnetic moment is the most basic principle is to measure a lot of magnetometer to measure the magnetic moment of the sample, then convert For the other parameters. The measurement of magnetic moment of magnetic nano materials can be measured in accordance with the size of the sample magnetometer is divided into three categories, the first chapter introduces the single magnetic nanoparticle magnetic moment measurement methods: magnetic force microscopy, Lorenz microscopy; micro nano magnetic polymer for collective magnetic moment measurement methods: Superconducting quantum interferometer, GMR sensor, the magneto-optical Kerr effect instrument: for a large number of magnetic particle aggregates magnetic moment measurement methods: vibrating sample magnetometer, magnetic balance, electron paramagnetic resonance instrument. The principle and the development of various methods. The main research content and results of this thesis are as follows: the second chapter analyzes the magnetic moment measurement has important significance for magnetic properties study of magnetic materials and magnetic interactions between particles will affect the magnetization, thereby changing the size of the magnetic moment. Considering the magnetic nanoparticles The interaction between particles in colloidal particles, we propose a new method of dynamics and the technology of digital image processing measurement of magnetic nanoparticle colloid droplets based on the micro magnetic moment. The magnetic nanoparticle colloid aqueous phase (2uL) in the same organic liquid and the density of magnetic colloidal droplets in the water tension. The formation of spherical and suspended in the organic solution. Then the gradient magnetic field, colloid droplets under the action of magnetic force, the magnetic field is increased along the direction of motion. The force analysis of droplet horizontal colloidal liquid, a liquid droplet velocity, acceleration, viscous resistance and magnetic equations, which can be measured by the droplet the velocity, acceleration, droplet by magnetic force, which calculate the magnetic moment of droplets. In the second chapter, the computer numerical simulation experiment, proved the feasibility of the method and the shadow. Factors affecting the sensitivity of the measurement are analyzed, concluded that the image acquisition device acquisition faster, the higher the sensitivity of magnetic moment measurement. The third chapter introduces the experimental device, the use of Ansoft software to the device in the "C" type electromagnet field distribution was simulated, and the use of teslameter measured magnetic field strength and the measurements are four order polynomial fitting and distance relationship, then obtain the functional relationship between the magnetic field gradient and the distance of polynomial derivation. Organic concentration distribution and magnetic nano solution the observed magnetic nano particles to form spherical and suspended in the organic phase, the gradient magnetic field, the droplet in the process of movement always keep uniform spherical. So, we can combine magnetic nanoparticle colloid droplets as a whole is analyzed. The fourth chapter and the fifth chapter is the core of this paper, the fourth chapter measurement The different sizes of the magnetic nanoparticle colloid droplet size of magnetic moment, prove that when the magnetic field direction and droplet motion in the same direction, and the magnetic dipole effect between magnetic particles will enhance the magnetization. In the experiment, different sizes of -Fe2O3 and DMSA@Fe2O3 gamma nano magnetic moment M colloidal droplet were measured. Two all of the materials by the hydrodynamic size of 82nm y-Fe2O3 magnetic nanoparticles was prepared. The hydrodynamic size of 598nm gamma -Fe2O3 magnetic nano colloidal droplets is greater than the total magnetic moment of the hydrodynamic size of 83nm DMSA@Fe203. and magnetocaloric effect strength and hydrodynamic size are positively correlated. In addition, from the results of measurement the magnetic moment of Fe3O4 magnetic nano colloidal droplets of different sizes can be seen in the magnetic nanoparticle colloid droplet size close to the hydrodynamic size close to the magnetic moment. The hydrodynamic size of large droplets in the magnetic field. Next, there was an obvious agglomeration movement in the process of the droplet is solid-liquid separation. The magnetic moment is significantly greater than the hydrodynamic size smaller droplets. The magnetic measurement data shows the method can measure magnetic moment in different hydrodynamic size of magnetic nanoparticles colloid fluid droplets. In the fifth chapter. We take the concentration were 6mg/ml, 3mg/ml, 1.5mg/ml, DMSA@Fe2O3 magnetic nano colloidal 0.75mg/ml, also use the new method proposed in this paper the four concentration of the colloidal droplets were measured simultaneously using magnetic moment, vibrating sample magnetometer and magnetic balance on the saturation magnetization and magnetic susceptibility measurements were carried out. The four kinds of materials in magnetic heat 5 minutes heating value was measured and calculated the magnetocaloric effect and the method of measuring magnetic moment, vibrating sample magnetometer measuring saturation magnetization and magnetic susceptibility of balance measurement Linear correlation coefficient and linear correlation of 0.986,0.844,0.945. show that the magnetic moment measured by this method can quantitatively reflect the magnetocaloric effect of the material.

【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;R318.08

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