一锅法高效制备橙色荧光氧化石墨烯量子点及其在细胞pH成像中的应用

以价廉、易得的石墨片为原料,采用改进的Hummers法,简单、快速、高效地制备了具有良好生物相容性的橙色荧光氧化石墨烯量子点(GOQDs)。所制备的GOQDs尺寸约7.2 nm,具有尺寸均匀、晶格间距为0.20 nm的高度结晶的核心和氧化的外围结构。与大多数报道的碳点(CDs)、包裹掺杂碳点(掺杂 CDs)、石墨烯量子点(GQDS)和 GOQDs不同,我们的方法制备的 GOQDs显示出橙红色并具有激发波长独立的荧光发射。此外,GOQDs具有pH依赖性荧光发射、强的光漂白抗性、低细胞毒性、良好的水溶性(ρ=10 mg·mL^-1)和优异的生物相容性。这些特性使其成功应用于细胞pH成像。     

一锅法高效制备橙色荧光氧化石墨烯量子点及其在细胞pH成像中的应用

以价廉、易得的石墨片为原料,采用改进的Hummers法,简单、快速、高效地制备了具有良好生物相容性的橙色荧光氧化石墨烯量子点(GOQDs)。所制备的GOQDs尺寸约7.2 nm,具有尺寸均匀、晶格间距为0.20 nm的高度结晶的核心和氧化的外围结构。与大多数报道的碳点(CDs)、包裹掺杂碳点(掺杂CDs)、石墨烯量子点(GQDS)和GOQDs不同,我们的方法制备的GOQDs显示出橙红色并具有激发波长独立的荧光发射。此外,GOQDs具有pH依赖性荧光发射、强的光漂白抗性、低细胞毒性、良好的水溶性(ρ=10 mg·mL^-1)和优异的生物相容性。这些特性使其成功应用于细胞pH成像。     

氮掺杂石墨烯量子点的制备及其在细胞成像中的应用

为克服现有量子点制备技术中存在的荧光量子产率较低及生物相容性差的问题,通过一步水热法合成一种高荧光量子产率的氮掺杂石墨烯量子点(N?GQDs),其荧光量子产率为94％.N?GQDs粒径在20～40 nm之间,最大激发波长为390 nm,发射波长为450 nm.N?GQDs呈现亮蓝色荧光,具有良好的光致发光作用.N?GQ...     

葡萄糖酸碳量子点的合成及其光学性能的研究

以葡萄糖酸为碳源,采用微波法、热解法和水热溶液法合成了水溶性较好的蓝色荧光碳量子点。用透射电镜(TEM)观察其形貌,荧光光谱(FL)和紫外可见光谱(UV)探究其激发和发射光谱,用时间分辨光谱(TRF)测其荧光寿命值。微波和热解法制备的碳量子点粒径在2.5~7.5 nm之间,激发波长为360 nm,发射波长为450 nm,荧光发射依赖激发波长,有三个荧光寿命,表面状态不均一。水热法制备的碳量子点,粒径在3.0~8.5 nm之间,激发波长为350 nm,发射波长为430 nm,荧光发射不依赖激发波长,只有一个荧光寿命值,表面状态均一。水热法合成的碳量子点荧光量子产率高为6.01%,为进一步研究葡萄糖酸制备碳量子点提供参考。     

水溶性荧光聚合物纳米粒的制备及双光子成像

报道了一种能用于活细胞双光子荧光(TPF)成像的水溶性聚合物纳米粒。首先以含双羧基的萘酰亚胺作为交联剂和荧光标记试剂,通过对聚乙烯亚胺发生交联反应制备纳米粒子,然后对其结构形态、单双光子荧光性能及细胞毒性进行测试。结果表明,获得的纳米粒为球形,粒径为5~10 nm;以443或800 nm为激发波长,荧光发射波长均为536 nm;在pH 4.0~9.0范围内,其荧光无明显变化;在pH 7.4的溶液中和激发光为443 nm的条件下,对其连续测定1.2万次后荧光强度变化不超过1%,说明其酸碱稳定性和光稳定性较好;浓度在15 mg/L以下及与细胞作用时间在24 h以内细胞毒性较低。最后,用双光子共聚焦荧光显微镜观察了其在Hela细胞中的TPF成像性能。将Hela细胞与纳米粒共同孵育2 h后,在800 nm激光激发下,在细胞中可观察到其绿色荧光。此纳米粒可望用于靶向性双光子荧光成像探针的开发。     

聚丙烯酸/萘酰亚胺纳米粒荧光增强法测定蛋白质

制备了水溶性的聚丙烯酸/萘酰亚胺荧光纳米粒,并利用牛血清白蛋白(BSA)对其荧光的显著增强效应,建立了测定蛋白质的新方法。在pH=3.0磷酸盐缓冲溶液及室温条件下,该纳米粒与BSA的作用5 min内即完成。以444nm为激发波长,在535nm处测定纳米粒/BSA体系的荧光,其荧光强度增加与0.15~7.5μmol·L-1浓度范围内的BSA呈线性关系,检测限为0.095μmol·L-1。该方法简单、快速、灵敏且重现性好,用于BSA合成样品及牛奶样品中蛋白质的测定,回收率范围为96.7%~102.6%,相对标准偏差(RSD)在3.91%以内。     

水热法新型水溶性荧光碳点的制备及其性能研究

以阿拉伯糖和磷酸酪蛋白肽进行水热反应,制备水溶性多色荧光碳点,利用透射电子显微镜(TEM)、紫外吸收光谱(UV)、荧光光谱(FL)、红外光谱(FTIR)和X射线衍射(XRD)等对所制备碳点的粒径大小、吸收光谱、发光性质、表面基团等进行表征,并考察了其性能和对不同金属离子的识别作用。结果表明:制备的荧光碳点平均粒径为4.62 nm,其紫外最大吸收波长为281 nm,XRD峰值约为21°,可在紫外灯下发出明亮的荧光,最大发射波长为414 nm,且呈荧光多元发射。红外光谱分析表明存在—COOH,—NH2和—OH基团。该荧光碳点具有良好的性能,且对Cu2+和Fe3+有较强的选择性识别作用,其原因可能是荧光碳点的聚合导致粒径增大从而使荧光强度减弱。该碳点有望作为荧光探针用于检测分析和生物成像等领域。     

新型水溶性多色荧光碳点的制备及细胞成像研究

以鸡蛋清和牛奶分别与葡萄糖进行水热反应,制备水溶性多色荧光碳点,通过膜和柱层析分离纯化,利用透射电子显微镜(TEM)、紫外吸收光谱(UV)、荧光光谱(FL)、红外光谱(FTIR)等技术对所制备碳纳米粒子的粒径大小、吸收光谱、发光性质、表面基团进行表征。将所制备的碳点与小鼠黑色素瘤细胞共孵育,进行细胞成像应用评价。结果表明:制备的两种水溶性荧光碳点平均粒径分别为2.5 nm和4.9 nm,可在紫外灯下发出明亮的荧光,紫外最大吸收波长为250 nm。基于鸡蛋清或牛奶与葡萄糖反应制备的多色荧光碳量子点具有良好水溶性,其荧光光谱最大发射波长分别在410 nm和400 nm处,同时在660~800 nm激发波长范围内具有上转换性质,且荧光发射光谱随着激发光波长的增加发生红移。红外光谱表明存在—COOH、—NH2和—OH基团。细胞成像结果表明,在405 nm或488 nm激光照射下,所制备的碳点在细胞内的荧光成像清晰可见,而且在碳点浓度小于2.5 mg/mL时,均表现出较低的细胞毒性。     

机械研磨法制备荧光可调碳量子点

以有机小分子丙酮为前驱体,在碱性条件下,采用机械研磨法制备了蓝绿色荧光碳量子点(carbon quantumdots,CQDs-1),其荧光发射波长为500nm.加入氟化钾(或氯化钾)共同研磨后得到黄色荧光CQDs(CQDs-2,荧光发射波长为560nm),而加入溴化钾(或碘化钾)共同研磨得到红色荧光CQDs(CQDs-3,荧光发射波长为600 nm).通过紫外可见吸收光谱(UV-Vis)和荧光光谱(PL)测定了3种CQDs的光学性质;通过透射电子显微镜(TEM)、原子力显微镜(AFM)、X射线粉末衍射(XRD)和拉曼光谱(Raman)对制得的CQDs进行了形貌及结构表征,并推断了CQDs的形成机理.采用简单的机械研磨法制备的荧光可调CQDs具有低细胞毒性、良好的水溶性和生物兼容性,可进入肿瘤细胞用于细胞成像研究.     

脂溶性铕螯合物的水溶化及其荧光信号增强

以本文合成的脂溶性的含丙烯酸配体的铕离子螯合物为聚合单体,以合成的具有聚乙二醇单甲醚结构单元的大分子为引发剂,合成了以聚乙二醇单甲醚为水溶端、铕离子螯合物的聚合单元为脂溶端的两亲性嵌段荧光共聚物,并在超声波作用下制备了该共聚物的水溶性荧光胶束纳米粒。对此纳米粒进行了TEM、粒径分布和荧光光谱表征,同时研究了荧光信号增强、时间稳定性、光漂白性能和荧光的酸碱稳定性。结果表明,该水溶性的铕荧光纳米粒的粒径分布均一(约298nm),荧光信号增强作用明显,对紫外光和酸碱的抵抗能力显著增强。本文实现了脂溶性铕螯合物的水溶化及其荧光信号增强,预示着铕荧光螯合物纳米粒可以直接用于生物标记,并具有高灵敏生物分析的应用潜能。     

pH-Responsive hollow polymeric microspheres and concentric hollow silica microspheres from silica-polymer core-shell microspheres

Nearly monodispersed silica-poly(methacrylic acid) (SiO 2-PMAA) core-shell microspheres were synthesized by distillation-precipitation polymerization from 3-(trimethoxysilyl)propylmethacrylate-silica (SiO 2-MPS) particle templates. SiO 2-PMAA-SiO 2 trilayer hybrid microspheres were subsequently prepared by coating of an outer layer of SiO 2 on the SiO 2-PMAA core-shell microspheres in a sol-gel process. pH-Responsive PMAA hollow microspheres with flexible (deformable) shells were obtained after selective removal of the inorganic SiO 2 core from the SiO 2-PMAA core-shell microspheres by HF etching. The pH-responsive properties of the PMAA hollow microspheres were investigated by dynamic laser scattering (DLS). On the other hand, concentric and rigid hollow silica microspheres were prepared by selective removal of the PMAA interlayer from the SiO 2-PMAA-SiO 2 trilayer hybrid microspheres during calcination. The hybrid composite microspheres, pH-sensitive hollow microspheres, and concentric hollow silica microspheres were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray (EDX) analysis.     

硫化锌纳米空心球：合成及光学性质研究

Cubic ZnS hollow nanospheres have been prepared by a simple and template-free solvothermal method. The reaction was accomplished between Zn powder and the in-situ prepared S8. The results of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) show that the ZnS hollow spheres are composed of ultrafine nanoparticles. The average diameters of the hollow nanospheres are about 100 nm. Their photoluminescence (PL) spectra indicate that they have excellent optical properties.     

水热法制备多层核壳结构Gd_2O_3:Eu~(3+)空心微球

以稀土硝酸盐-葡萄糖的混合溶液作为前驱体,采用一步水热法和随后的热处理得到了多层核壳结构Gd_2O_3:Eu~(3+)空心微球,并用X-射线衍射(XRD)、场发射扫描电镜(FESEM)、透射电镜(TEM)、X-射线能量色散光谱(EDS)和荧光光谱等测试手段对所得样品进行了表征.结果表明:所得空心球样品为纯的立方相的Gd_2O_3.具有规则的多层核壳空心结构,空心球的直径在2～3μm左右,壁厚约为100 nml,并且Gd_2O_3:Eu~(3+)空心球是由尺寸约为30 nm的球形纳米颗粒白组装而成.样品中含有Gd、Eu、O元素.该空心球样品具有强的Eu~(3+)的特征红光发射以及长的荧光寿命,可以用来作为时间分辨荧光标记物.     

Influence of surfactant concentration on the surface morphology of hollow silica microspheres and its explanation

The surface morphology of hollow silica microspheres has influence on their applications. After a thorough investigation of the deposition of silica nanoparticles on polystyrene (PS) beads and the surface morphology and texture of the resultant hollow silica shells with scanning electron microscopy, transmission electron microscopy, and N2-sorption measurements, the influence of surfactant [cetyltrimethylammonium bromide (CTAB)] concentration on the surface morphology of hollow silica microspheres templated by PS beads is explained. Previously, CTAB was believed to turn the surface charge of PS beads from negative into positive so that negatively charged silica could be deposited on the PS template. Here, we show CTA+ cations preferentially assemble with silica species to form silica-CTA+ composite nanoparticles. Since the zeta potential of silica-CTA+ composite nanoparticles is smaller than that of pure silica nanoparticles, these composite nanoparticles encounter less repulsion when they are deposited on the surface of PS beads and close to each other. As more CTAB is added, the silica-CTA+ nanoparticles are less negatively charged, and more compact and smooth hollow silica microspheres are obtained.     

Fabrication of symmetric hierarchical hollow PbS microcrystals via a facile solvothermal process

Symmetric hierarchical hollow PbS structures consisting of nanowalls were successfully fabricated by a facile solvothermal process in ethylenediamine at 120 degrees C for 12 h, employing lead acetate trihydrate and dithizone as precursors; the thickness of the nanowalls is about 80 nm. No surfactants or other templates were used in the process. The synthesized product was characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), electron diffraction (ED), ultraviolet-visible spectrometer (UV-vis), near-infrared absorption spectroscopy (near-IR), and fluorescence spectrophotometer. The effect of the reaction conditions on the size and morphologies of PbS structures was investigated. The results show that the temperatures, solvent, and sulfur sources are crucial factors on the morphologies and sizes of the symmetric hierarchical hollow PbS microcrystals. A possible growth mechanism of hierarchical hollow PbS structures is presented. UV-vis absorption spectrum holds a weak peak at 253 nm; the near-infrared absorption spectrum of PbS microcrystals has the two absorption peaks centered at 9613 cm(-1) (1040 nm) and 6771 cm(-1) (1477 nm), showing a blue shift compared with the bulk PbS (approximately 3020 nm). And the fluorescence spectrum of PbS microcrystals consists of an emission peak with a maximum at 305 nm. These PbS microcrystals may have potential applications in the fundamental study of nanostructures as well as fabricating nanodevices.     

简单方法制备羟基磷灰石中空微球

无需添加任何有机物和金属离子, 以易得的中空球形碳酸钙(CaCO3)与磷酸氢二钠(Na2HPO4)作为反应物在常压下制备出羟基磷灰石中空微球. 通过场发射扫描电子显微镜(FESEM)、扫描电子显微镜(SEM), X射线粉末衍射(XRD)等手段对制备的羟基磷灰石中空微球的结构、组成和形貌进行了表征, 考察了不同反应温度对中空球形貌的影响. 实验结果表明, 所制备的羟基磷灰石微球是由短针状的纳米粒子组成的, 直径为2-4 μm. 对反应机理进行了初步探讨.     

Synthesis and characterization of dually labeled Pickering-type stabilized polymer nanoparticles in a downscaled miniemulsion system

Dual fluorescently labeled polymer particles were prepared in a downscaled Pickering-type miniemulsion system. Stable dispersions were obtained and the size of the hybrid particles could be varied between ca. 180 and 430 nm. Silica nanoparticles were employed as sole emulsifier, which were labeled by a fluorescein dye (FITC) or (encapsulated) quantum dots, and the polymer core was labeled by a perylene derivative. Downscaling of the Pickering-type miniemulsion system is intriguing by itself as it allows the use of precious nanoparticles as emulsifiers. Here, silica particles with a fluorescent core and an overall diameter between 20 and 40 nm were prepared and employed as stabilizer. The dual excitation and emission of both dyes was tested by fluorescence measurements and confocal laser scanning microscopy (cLSM).     

纳米CaCO3负载过渡金属CVD法制备多壁碳纳米管的研究

以纳米碳酸钙粉体为载体,用浸渍法制备了可用于化学气相沉积(CVD)法制备碳纳米管的高产率催化剂.应用FESEM,HRTEM,TEM,XRD和激光拉曼谱对产物进行了表征.结果表明,由于纳米碳酸钙具有较大的比表面积,可高密度地承载催化剂活性组分.在碳纳米管生长初期,处于缓慢分解状态的纳米碳酸钙才能有效地起到载体作用,且反应温度为700～750℃时,碳纳米管的产率较高.Fe-Co双金属催化剂在700℃,催化生长60min后,可增重10倍,而且产物中无定形碳含量极少.纳米碳酸钙载体易于提纯,用质量分数为30%的硝酸超声提纯粗产品1h,可使纯度提高到97%,且不破坏碳纳米管结构.     

内部具有可移动金核的中空银纳米颗粒的制备、表征及其表面增强拉曼效应

采用振荡法和种子生长技术制备出核壳结构的Au@SiO2纳米颗粒及夹层结构的Au@SiO2@Ag纳米颗粒, 用HF将Au@SiO2@Ag NPs夹层的SiO2溶解, 得到内部带有粒径为30 nm的可移动金核、壳层厚度约为30 nm的中空银纳米颗粒(Au@air@Ag NPs). 用扫描电子显微镜和透射电子显微镜对所得到的纳米微球的形貌进行了表征, 并以罗丹明B为探针分子研究了Au@air@Ag 纳米颗粒的表面增强拉曼(SERS)效应, 发现Au@air@Ag 纳米颗粒是一种可应用于SERS的理想材料.     

以卵磷脂为手性添加剂制备手性介孔二氧化硅

以十六烷基三甲基溴化铵(CTAB)的自组装体为模板,卵磷脂(PC)为手性添加剂,在n_PC:n_CTAB=1:21时,通过溶胶-凝胶法制备了螺旋介孔二氧化硅纳米棒。利用扫描电镜(FESEM)、透射电镜(TEM)、X-射线衍射以及氮气吸附-脱附等测试手段,对该纳米棒的形貌以及孔结构进行了表征。TEM显示该纳米棒的长度约为50~200nm,直径约为30~50nm。X-射线衍射表明孔道呈二维六方排列,虽然FESEM显示纳米棒左右手比例约为1:1,但通过圆二色谱表征证明该纳米棒在埃尺度下倾向于形成单一手性。结果表明,卵磷脂的手性可以传递到螺旋介孔二氧化硅纳米棒中。