【作者】 司华艳；

【导师】 张浩力；

【作者基本信息】 兰州大学 ， 有机化学， 2009， 博士

【摘要】 本文的主要研究工作是制备多种表面功能化的纳米粒子,并应用其构筑多种新型的纳米复合材料,我们对所得材料进行了深入的结构表征,研究了其结构与光学、电学性质的关系,探讨这些新材料在光电器件与生物医学领域的应用前景。主要工作如下:1.制备了高度有序的CdSe/TiO₂纳米复合材料,并研究了其光电转化性能。首先通过高温热解的方法合成了不同尺寸的CdSe量子点。随后,通过双官能团巯基乙酸将CdSe量子点组装到多孔的锐钛矿TiO₂薄膜表面,首次得到了CdSe量子点敏化的TiO₂薄膜,成功地将其光谱响应区拓展到可见光区。2.制备了间距可控的CdSe/CNT纳米复合材料,实现了对CdSe量子点与碳纳米管之间的光致电荷传递过程的调控。首先使用三种不同长度的含巯基的羧酸修饰CdSe量子点的表面,得到具有不同厚度的核/壳结构。然后通过静电自组装的方法,成功制备了CdSe/CNT复合材料。复合物CdSe/CNT的荧光效率随着壳层厚度的增加而增大,证明我们有效地控制了CdSe与CNT之间的电荷转移。3.我们设计并合成了OPE（oligo（phenylene ethynylene））与CdSe量子点的纳米复合物,并研究OPE与CdSe量子点之间的能量转移。通过OPE分子导线的端基巯基,使其固定到CdSe量子点表面,形成CdSe/Den-OPE复合物。我们研究了CdSe/Den-OPE复合物的荧光性质。由于能量转移和电荷转移,分子导线的荧光很大程度的淬灭,伴随着量子点荧光的增强。4.利用交联法制备了Fe₃O₄/壳聚糖纳米复合物,然后通过共价反应将抗癌药物染料木黄酮连接在纳米复合物表面,形成了一种多功能的纳米载药体系。以胃癌细胞株SGC7901为实验对象,用噻唑蓝（MTT）比色法观察纳米粒子载药体系和染料木黄酮对其增殖活性的影响;采用流式细胞术检测癌细胞的凋亡率。相对于染料木黄酮分子,纳米载药体系表现了更高的抗肿瘤活性。这种纳米复合物在结合药物可控释放和磁性热疗的多功能化疗方面有潜在用途。更多还原

【Abstract】 In this work,a series of surface functionalized nanopaticles were synthesized, and based on which novel nanohybrid materials were designed and fabricated.The structural,electronic and spectroscopic properties of the obtained nanohybrid materials were characterized to explore their potential applications in the fields like optoelectronics and biology.The main results are as below:1.CdSe quantum dots（QDs） modified porous TiO₂ films were prepared and their photo energy conversion efficiencies were studied.CdSe QDs with different sizes were prepared by pyrolytic method.Meanwhile,anatase form of TiO₂ thin films were prepared by anodic oxidation of titanium plates.By using bifunctional linkers modifiers,CdSe quantum dots（QDs） were assembled onto mesoscopic anatase TiO₂ films to give CdSe QDs sensitized TiO₂ thin films.The photoactivities of the new nanostructures under visible light illumination were investigated,and the possible electron transfer mechanism between CdSe QDs and the TiO₂ film was discussed.2.Novel nanohybrids containing carbon nanotubes（CNTs） and CdSe quantum dots （QDs） were prepared through electrostatic self-assembly method.The CdSe QDs were capped by three mercaptocarboxylic acids,including thioglycolic acid（TGA）, dihydrolipoic acid（DHLA） and mercaptoundecanoic acid（MUA）,which provide shell thickness of 5.2,10.6 and 15.2 angstroms,respectively.The photoluminescence （PL） efficiencies of the CdSe/CNT nanohybrids increase significantly with the increase of the shell thickness,which is attributed to a distance-dependent charge transfer mechanism.This work demonstrates a simple mean for fine tuning the PL properties and gains new insights to the charge transfer in such CdSe/CNT nanostructures.3.The energy transfer with in a series of nanocomposites consisting molecular wires and CdSe Qds were investigated.Thiol-substituted dendrimer encapsulated "core-shell" molecular wires（Den-OPE） were used to functionalize CdSe QDs. Attachment of the molecular wires to the CdSe QDs resulted in little change to the electronic structure of the molecular wires,as shown by the absorption spectra.The emission spectra of the CdSe/Den-OPE composite showed that Den-OPE molecular wires emission was quenched,while the emission of CdSe QDs was enhanced due to either an electron or an energy transfer mechanism.4.A multifunctional drug delivery system for the anti-cancer drug genistein has been devised,which is based on covalently attaching genistein onto the Fe₃O₄ nanoparticles coated with cross-linked carboxymethylated chitosan（CMCH）.The nano-conjugate shows good water solubility and superparamagnetic properties.The effects of genistein and Fe₃O₄-CMCH-genistein nano-conjugate on the proliferation and apoptosis of gastric cancer cell line SGC-7901 were investigated by MTT assay and flow cytometry.Compared with free genistein,the nano-conjugate shows much higher anti-tumor effect.This drug delivery system is promising for future multifunctional chemotherapeutic application that combines drug release and magnetic hyperthermia therapy.更多还原