【作者】 陈凡；

【导师】 韦玮；

【作者基本信息】 南京邮电大学 ， 光学工程， 2017， 硕士

【摘要】 生命科学的研究已深入至细胞、生物单分子层次。近年来,随着纳米技术、生物技术与材料制备技术的飞速发展,稀土发光纳米材料作为新型的生物发光标记材料,被广泛应用于荧光成像中。与传统的荧光探针（如有机荧光染料和半导体量子点）相比,稀土发光纳米材料具有荧光寿命长、发射光谱带窄、Stokes位移较大、光化学稳定性强以及生物毒性小等优点,因此,稀土发光纳米材料在荧光免疫分析、生物分子标记、发光共振能量转移和细胞成像等方面具有非常大的应用潜力,用于生物荧光标记的稀土发光纳米材料的制备与性能研究受到了人们广泛的关注。稀土纳米材料用于生物成像的前提是具有亲水性、小尺寸（一般小于50nm）、表面有活性基团以增加生物相容性并利于进一步连接生物分子,因此本论文在课题组前期研究的基础上,通过采用水溶性聚合物对纳米颗粒进行表面修饰,一步水热制备了一系列不同形貌、尺寸的紫外-可见和近红外-近红外稀土发光纳米材料,并利用这种纳米颗粒作为荧光探针开展了HeLa细胞的荧光成像和毒性检测实验。本论文具体研究工作如下:（1）在课题组前期研究的基础上,分别通过改变聚丙烯酸的量、反应温度、反应时间等条件,优化聚丙烯酸（PAA）修饰的掺铕氟化镧纳米颗粒（LaF₃:Eu@PAA）,所得的纳米颗粒在PBS中表现出良好的分散稳定性和光稳定性。（2）对LaF₃:Eu（50 mol%）@PAA纳米颗粒进行细胞实验。经过改变孵育时间和浓度,得出了较适宜的材料培养浓度与细胞孵育时间。在515nm波长激发下,纳米颗粒发出红色荧光,且荧光集中在HeLa细胞内部,该结果表明这种纳米材料对HeLa细胞具有低毒性,本纳米颗粒作为紫外-可见水溶性纳米材料可用于生物成像。（3）利用一步水热法合成了叶酸（FA）修饰的掺钕氟化镧纳米颗粒（La F₃:Nd@FA）,该纳米颗粒尺寸为10nm左右,FA分子链接在纳米颗粒表面,使纳米颗粒在去离子水、磷酸盐缓冲液（PBS）中的分散性、稳定性均良好,XRD与标准比色卡相匹配,红外光谱（FT-IR）、荧光光谱（PL）及寿命衰减图与文献中报道一致。将LaF₃:Nd（3 mol%）@FA与HeLa细胞进行培养,高浓度LaF₃:Nd@FA纳米颗粒对细胞表现出低毒性。结果表明该纳米颗粒可作为近红外-近红外（NIR-NIR）水溶性纳米材料用于生物成像。更多还原

【Abstract】 Research on biological science has been deep into the cell and molecule level.In recent years,with the rapid development of nanotechnology,biotechnology and material technology,rare earth luminescent nanomaterials have been widely used in fluorescence imaging as a new bioluminescent marker material.Compared with traditional fluorescent probes（such as organic fluorescent dyes and semiconductor quantum dots）,rare earth luminescent nanomaterials have the advantages of long fluorescence lifetime,narrow emission band,strong Stokes shift,strong photochemical stability and small bio-toxicity.So rare earth luminescent nanomaterials have great potential in fluorescence immunoassay,biomolecule labeling,luminescence resonance energy transfer and cellular imaging.The preparation and performance of rare earth luminescent nanomaterials for biofluorescence labeling have attracted researchers’ attention.Rare earth nanomaterials used in biological imaging should be hydrophilic,small in size（typically less than 50 nm）,with active groups on the surface to increase biocompatibility and facilitate further attachment of biomolecules.Therefore,in this paper,based on the surface modification by water-soluble polymer,a series of ultraviolet-visible and near-infrared-near-infrared rare earth luminescent nanomaterials with different morphologies and sizes were prepared by hydrothermal method.Fluorescence probes were incubated with HeLa cells to test the cellular imaging and toxicity.The specific work of this paper is as follows:（1）La F₃:Eu（50 mol%）@PAA modified by polyacrylic acid（PAA）was optimized by changing the amount of polyacrylic acid,reaction temperature and reaction time respectively.The results show that the nanoparticles showed great dispersion stability and photostability in PBS.（2）La F₃:Eu（50 mol%）@PAA nanoparticles were subjected to cell experiments.After changing the incubation time and concentration,the optimum culture time and cell incubation time were obtained.At the wavelength of 515 nm,the nanoparticles emitted red fluorescence and the fluorescence was concentrated inside the He La cells.The results show that the nanomaterials have low toxicity to HeLa cells.The nanosized particles can be used as biosynthesis as UV-visible water-soluble nanomaterials.（3）LaF₃:Nd@FA modified by folic acid（FA）was synthesized by one-step hydrothermal method.The nanoparticles were about 10 nm in size.The FA molecules were linked to the surface of the nanoparticles,FT-IR,fluorescence spectroscopy（PL）and lifetime attenuation were consistent with those reported in the literature,and the dispersibility and stability were good in XRD and standard colorimetric cards.Being incubated with HeLa cells,high concentration of LaF₃: Nd（3 mol%）@FA nanoparticles showed low toxicity to cells.The results show that the nanoparticles can be used as near infrared（NIR-NIR）water-soluble nanomaterials for biological imaging.更多还原