【作者】 黎雪莲；

【导师】 李庆； 李长明；

【作者基本信息】 西南大学 ， 分析化学， 2013， 博士

【摘要】 由于纳米尺寸的物质具有与宏观物质迥异的小尺寸效应、表面与界面效应、量子尺寸效应、宏观量子隧道效应等,因而纳米材料具有特殊的光、电、热、磁、力学等性能。如何构建具有磁性、光学、电学、催化等性能的多功能化纳米复合材料,并将其有效应用于生物医学、环境科学、食品安全等领域,已经成为研究者们关注的焦点。本论文从功能化纳米复合材料的制备、表面修饰、形貌及磁/光/抗菌/毒学等性能的研究出发,构建了五种纳米复合材料并探讨了它们在生物分析领域的应用。本论文主要分为以下几个部分：第一章综述简要概述了纳米材料的特性及应用,详细介绍了本论文所涉及的三种纳米材料(碳纳米管、CdTe量子点和Fe304磁性纳米粒子)的常规制备方法以及表面功能化修饰方法。另外,着重评述了基于这几种纳米材料所构建的纳米复合材料在生物医学、环境科学、刑事侦探等领域的应用。第二章碳纳米管/壳聚糖/聚合物纳米复合材料修饰的微阵列生物传感器。本文制备了由碳纳米管/壳聚糖/PVI-Os氧化还原聚合物所形成的纳米复合物,并将其用于一种新型可印刷的微阵列电化学传感器,实现了血清中葡萄糖和乳酸的同步检测。复合物作为传感器的敏化层由带负电的碳纳米管作为骨架将壳聚糖/PVI-Os交联起来,而带正电的壳聚糖/PVI-Os作为氧化还原媒介体并使葡萄糖氧化酶和乳酸氧化脱氢酶有效地固定在微电极表面。CNTs/Chitosan/PVI-Os纳米复合材料具有多孔、比表面积大等特点,可有效的增加乳酸氧化酶/葡萄糖氧化酶的固载量。同时其网状结构和壳聚糖的生物相容性协同作用,可以避免酶的脱落。该传感器具有以下优点：(1)碳纳米管的网状结构和壳聚糖的生物相容性协同作用,使更多的酶固定在微电极上且不易脱落、变性,提高传感的灵敏性；(2)通过在同一个芯片上设置无酶电极,可消除其他电活性物质的干扰,提高检测的特异性；(3)能同步检测多种待检组分,实现高通量的分析检测等；(4)制作成本低,可批量生产。该新型传感器具有灵敏度高、选择性好、抗干扰能力强和稳定性好等特点,在临床诊断方面有着很大的潜在应用价值。第三章量子点/多聚赖氨酸纳米复合多层膜的构建及其抗菌生物活性检测。CdTe量子点具有荧光发射波长随尺寸改变连续可调、发射光谱窄且对称分布、光化学稳定性佳等特性,己广泛应用于生物影像和生物传感等领域,但其抗菌生物活性尚不明确。本文在合成CdTe量子点时采用巯基丁二酸作稳定剂,大量的羧基(-COOH)使CdTe量子点表面带负电荷,不仅使CdTe量子点在水相中具有良好的分散性和稳定性,而且能进一步与聚阳离子电解质多聚赖氨酸(PLL)发生静电吸附作用,从而制备(CdTe QDs/PLL)多层膜纳米复合物。该纳米复合多层膜的厚度、荧光强度、抗菌性能均可通过组装层数的不同加以调控,且可通过修饰不同大小量子点材料达到改变吸收和发射特性的目的。采用本方法制备的(CdTe QDs/PLL)多层膜具有光致发光性能和良好的抗菌生物活性等优点,可将其应用于构建抗菌涂层装饰材料等。第四章超顺磁性氧化铁纳米颗粒的制备及其生物毒性的研究。具有独特磁响应性的超顺磁性氧化铁纳米颗粒(SPIONs)在生物传感、药物定向传输、医学诊断与治疗等领域已展示出巨大应用潜力,但是其生物毒性尚不清楚。本研究采用化学共沉淀技术,以聚乙二醇(PEG)为表面活性剂,制备了分散性好的超顺磁性四氧化三铁纳米粒子。采用场发射扫描电子显微镜、透射电子显微镜、动态光散射粒径分析仪、X-射线晶体衍射、振动磁强计对SPIONs纳米颗粒的大小、形貌、晶体类型及磁性进行了表征测试。结果显示,所获得材料为直径约10-16纳米的近似球形的四氧化三铁纳米粒子,其矫顽磁性和剩磁几乎为0emu/g,饱和磁化强度为68.6emu/g,表明该材料为超顺磁性纳米粒子。通过蛋白质芯片结合传统方法分析了SPIONs的毒性效应及其分子机制。结果表明,当浓度低于50μgmL-1。时,SPIONs不能诱导明显的生物毒性,为其在生物医学领域的应用提供了参考。第五章Fe3O4@SiO2-Au纳米复合材料的制备及其潜指纹显现的研究。磁性纳米粒子具有良好的磁响应性、易于与磁性物质牢固结合,在指纹显现与检测方面有较大应用潜力。本研究采用共沉淀法制备Fe304磁性纳米颗粒,将其表面氨基化后连接金纳米粒子,再用甲醛还原纳米金颗粒,制备得到粒径约500nm、单分散性能良好的Fe3O4@SiO2-Au纳米复合材料。将该复合材料应用于潜指纹的检测,具有以下优点：(1)其粒径半径小于传统的粉显法颗粒半径,因此,显现效果好；(2)利用氨基硅烷(APTES)网状结构,既能防止Fe304的沉聚,使其具有良好的分散性和稳定性,又能在其表面修饰纳米金等易于与氨基酸、蛋白质结合的纳米粒子：(3)能有效与指纹中的氨基酸、蛋白质牢固结合,又具有金纳米粒子的特性,能够提高潜指纹显现灵敏度；(4)具有良好的磁性,因此,潜指纹显现后,多余的磁珠可以用磁性刷子吸取,避免纳米颗粒粉尘对检测人员身体的伤害；(5)能够显现遗留在不同客体表面(如玻璃、纸张、塑料等)的潜在指纹,具有更广泛的应用价值。第六章Fe3O4@SiO2/FITC/Au磁-光双功能纳米复合粒子的制备及其潜指纹显现的研究。磁性发光材料兼具磁性和发光性能,在生物医学领域具有潜在的应用前景,引起了科研者的广泛关注。本文用荧光性物质对磁性材料进行修饰后,再与金纳米粒子结合,发展了一种新颖的制备Fe3O4@SiO2/FITC/Au磁-光双功能复合粒子的方法,该方法制备出的磁-光双功能复合粒子具有磁性、荧光性及易与生物样品牢固结合的特性。该复合粒子具有荧光,可用于深色背景载体上潜指纹的显现；表面丰富的金纳米粒子,易与指纹中的蛋白质和氨基酸等结合；而且该复合粒子毒性低,其超顺磁性可有效降低刑侦人员吸入粉尘的危害。因此,与其他显现潜指纹的荧光材料、传统磁粉相比,该复合粒子具有更多优势,不仅可以用于法庭科学浅指纹显现,在生物医学、环境科学领域也会产生潜在的应用价值。更多还原

【Abstract】 Unique characteristics of nanomaterials including small size effect, surface and interface effect, quantum size effect, as well as macroscopic quantum tunnel effect result in specific optical, thermal, electrical, magnetic, and mechanical properties. Many researchers concentrate their efforts on design and fabrication of multifunctional nanocomposites with magnetic, optical, electrical, catalytic properties for various applications in biomedicine, environmental science, food safety and other fields. This thesis focuses on the fabrication and functionalization of nanocomposites and investigates their potential applications in bioanalysis. The thesis is divided into the following six parts:1. Literature review. First, properties and applications of nanomaterials are briefly introduced. Second, fabrication and surface modification of three nanomaterials (carbon nanotubes, CdTe quantum dots and Fe3O4magnetic nanoparticles) involved in this thesis are summarized one by one. In addition, the applications of these nanomaterials-based nanocomposites in biomedical diagnosis, environment science, and criminal detection are reviewed in detail.2. Title:microarray biosensor based on carbon nanotubes/chitosan/polymer nanocomposites. It is very challenging to fabricate bioarrays to electronically high-throughput detect multiple analytes. This work innovatively fabricates an integrated printed circuit board (PCB)-based array sensing chip to simultaneously detect lactate and glucose in a biological sample, providing high sensitivity, high specificity and reproducibility. The novelty of the chip relies on a concept demonstration of inexpensive high-throughput electronic biochip, a chip design for high signal to noise ratio and high sensitivity by construction of positively charged chitosan/redox polymer Polyvinylimidazole-Os (PVI-Os)/carbon nanotube (CNT) composite sensing platform, in which the positively charged chitosan/PVI-Os is mediator and electrostatically immobilizes the negatively charged enzyme, while CNTs function as an essential cross-linker to network PVI-Os and chitosan due to its negative charged nature. The nanocomposite has a porous network structure with large specific surface area, which may contribute to the high loading capacity of enzymes. The developed sensing biochip possesses the following advantages:(1) low cost and easy for mass production;(2) the network structured carbonanotubes and biocompatible chitosan synergistically improve the performance of sensors, resulting from high enzyme loading capacity, good stability and high activity of immobilized enzyme.(3) Additional electrodes on the chip with the same sensing layer but without enzymes were prepared to correct the interferences to achieve high specificity and selectivity;(4) multiple analytes can be simutaneously detected with a single chip in high-throughput format. The developed sensing chip shows high sensitivity, good selectivity and reproducibility, providing great potential applications in biomedical diagnosis.3. Title:(CdTe QDs/PLL) layer-by-layer multilayer film and its antibacterial properties. CdTe quantum dots have many unique properties such as adjustable size-dependent fluorescence emission, broad excitation and narrow emission spectra, as well as good photochemical stability. In this thesis CdTe quantum dots are synthesized via hydrothermal approach with mercaptosuccinic acid, which contains negatively charged carboxyl groups, as protection ligands to improve the dispersability and stability.(CdTe QDs/PLL) multilayer films are then prepared via electrostatic layer-by-layer assembly of the nagtively charged QDs and positively charged polycation electrolyte (PLL). The thickness, fluorescence intensity and antibacterial activity of the film can be simply adjusted by controlling assembly layer numbers. The absorbance and emission of the film can be also tailored by changing QDs with various sizes. Using this method, the prepared (CdTe QDs/PLL) multilayer films have good photoluminescence and exciting antibacterial properties. It may have potential application as an antibacterial decoration coating.4. Title:Coprecipitation preparation of superparamagnetic iron oxide nanoparticles and their nanotoxicity Due to the easy manipulation with an external magnetic field and unique physiochemical properties, SPINOs have offered broad biomedical applications including high-resolution magnetic resonance imaging (MRI), in vitro bioseparation, magnetic targeted drug delivery, and hyperthermia therapy, In this work SPIONs were synthesized via chemical coprecipitation method with polyethylene glycol (PEG) as surfactant. The resultant nanoparticles were characterized with field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). Results show that as-prepared nanocrystals are roughly spherical with reasonably uniform size from10nm to16nm in diameter; high saturation magnetization intensity (68.6emu/g) and zero coercivity and remanence. SPIONs-induced nanotoxicity and its molecular pathways were further investigated by protein microarrays with assistance of conventional methods. The experimental results reveal that<50μg/mL SPIONs don’t induce significant nanotoxicity, providing valuable information for biomedical applications. 5. Title:Fabrication of functional Fe3O4@SiO2-Au nanocomposites for latent fingerprints enhancement. Magnetic nanoparticles can be easily manipulated with an external magnetic field, providing a great potential for applications in latent fingerprint detection. In this work, magnetic Fe3O4nanoparticles were synthesized via coprecipitation method. A thin layer of SiO2was coated on surface of Fe3O4nanoparticlesto obtain Fe3O4@SiO2nanospheres. Gold nanoparticles were then attached onto the surface of aminated Fe3O4@SiO2nanoparticles, followed by reduction with formaldehyde to prepare Fe3O4@SiO2-Au nanocomposites. The as-prepared nanocomposites were employed for latent fingerprint detection, showing many advantages:(1) the small size of the prepared multifunctional nanoparticles gives better performance in comparison with conventional reagents;(2) SiO2coating significantly improve the dispensability and stability;(3) gold nanoparticles not only have good optical properties, but also provide favorable surfaces for amino acid and protein attachments;(4) Redundant magneticic nanoparticles can be easily removed by magnet brush, reducing their toxicity to operator;(5) The as-prepared nanocomposite can be universally used for latent fingerprinting detection on different substrates including glass, paper, plastic, etc.6. Title:Fabrication of magnetic and luminescent bi-functional Fe3O4@SiO2/FITC/Au nanocomposite for latent fingerprints enhancement. Luminescent magnetic nanoparticles with unique optical and magnetic properties have been widely used in biomedical fields, In this project, a novel Fe3O4@SiO2/FITC/Au luminescent magnetic bi-functional nanocomposite was prepared for latent fingerprinting detection. The bi-functional nanoparticles have the following advantages:(1) the luminescent feature can improve the detection performance especially on substrates with dark background;(2)(2) Amino acid and protein can be effectively adsorbed onto the surface of nanoparticles via gold nanoparticles as linker;(3) The nanocomposite has low toxicity and can be removed by magnet brush. The developed Fe3O4@SiO2/FITC/Au as a new fluorescent material shows superior performance for latent fingerprinting detection as compared with conventional magnetic powder and fluorescent materials, providing a great potential not only in penal investigation, but also in biomedicine and environmental science.更多还原