表面修饰CdS和(CdS)ZnS纳米晶的性能研究

在水相中合成了CdS纳米微粒,以ZnS对其进行表面修饰,得到具有核壳结构的(CdS)ZnS水溶性纳米晶。采用红外光谱、X射线衍射(XRD)、透射电镜(TEM)表征其粒度和形貌,紫外-可见吸收光谱(UV)、荧光光谱表征其光学特性。制得的CdS近似呈球形,直径为8nm;CdS纳米颗粒表面经ZnS修饰后,其荧光发射峰强度显著增强,表面态发射减弱。     

包裹RuBpy二氧化硅荧光纳米探针的制备及其用于肝癌细胞的识别

制备了两种不同官能团修饰的偶联亲和素的包裹钌联吡啶(RuBpy)二氧化硅荧光纳米探针A和探针B,并分别用于肝癌细胞的识别。通过反相微乳液法制备得到表面修饰不同官能团的纳米颗粒,然后通过亲和素与羧基化包裹RuBpy二氧化硅纳米颗粒相互连接而制备得到探针A;通过亲和素与PEG修饰的荧光二氧化硅纳米颗粒相互作用而制备得到探针B。与探针A不同的是,探针B通过一个长链PEG分子将亲和素与荧光二氧化硅纳米颗粒偶联在一起。利用免疫荧光成像法将这两种探针分别用于人肝癌细胞的识别,结果表明,含有长链PEG分子的探针B更能够有效地识别肝癌细胞表面肿瘤标志物癌胚抗原(CEA)。     

胃蛋白酶对CdTe纳米粒子的表面修饰及分析应用

以巯基乙酸为稳定剂和表面修饰剂, 在有机相中合成了平均粒径为3 nm左右的CdTe纳米粒子, 用胃蛋白酶改变纳米粒子的表面修饰状态并研究其系列特性. CdTe纳米粒子在320 nm处有强的紫外吸收, 在524.8 nm处有荧光发射. 经胃蛋白酶对其表面修饰后, 紫外吸收峰位不变, 但吸光强度升高, 荧光峰位蓝移至467.2 nm, 荧光强度降低. 温度、pH值及离子强度均对表面修饰产生影响. 在最佳实验条件下, 胃蛋白酶质量浓度在4—40 mg/L范围内与荧光降低值之间呈线性关系, 检测限(3σ)为0.28 mg/L(n=10), 该方法已被用于人体胃液胃蛋白酶的测定.     

聚合物纳米光诊疗剂的制备与应用新进展

共轭聚合物纳米颗粒是由π-共轭有机聚合物组成的尺寸在1~100nm范围内的新型有机纳米材料。与传统的有机小分子、半导体量子点和无机纳米材料相比,聚合物纳米颗粒具有光学性质特殊、结构多样、表面易修饰和生物相容性好等优点,因而被广泛应用于生物成像、传感与检测、载药和治疗等领域。本文主要围绕聚合物纳米颗粒的制备方法、性质结构和生物相容性等方面,重点介绍了聚合物纳米颗粒作为光诊疗剂在荧光成像、光声成像,以及光动力和光热治疗领域的研究进展,并对聚合物纳米颗粒的发展前景和未来面临的挑战进行了探讨。     

信号肽功能化二氧化硅纳米颗粒的线粒体靶向作用研究

以N-(p-Maleimidophenyl)isocyanate(PMPI)为交联剂, 将线粒体信号肽分子共价修饰到二氧化硅荧光纳米颗粒表面, 构建线粒体信号肽功能化二氧化硅荧光纳米颗粒. 采用荧光分光光度计、Zeta电位仪以及透射电子显微镜对修饰前后的二氧化硅纳米颗粒进行了表征. 结果表明, 信号肽可被成功修饰在纳米颗粒表面, 并且纳米颗粒粒径在信号肽分子修饰前后没有发生明显变化. 以分离纯化的细胞核作为对照, 采用流式细胞术考察了信号肽功能化二氧化硅荧光纳米颗粒与分离纯化后的线粒体的相互作用. 结果表明, 线粒体信号肽修饰到二氧化硅纳米颗粒表面后依然保持良好的生物活性, 能够介导二氧化硅纳米颗粒特异性识别及结合分离纯化的线粒体, 从而为线粒体监测及其功能调控研究提供了新的思路.     

罗丹明B硅纳米粒子探针及其在蛋白芯片检测中的应用

本工作将罗丹明B分子通过共价结合的方式成功地包裹在二氧化硅纳米粒子中,制备的纳米粒子荧光强度和罗丹明B分子相比提高了1000倍.对此硅纳米荧光粒子进一步进行了链亲和素修饰,成功制备了可特异性结合生物素修饰蛋白的纳米荧光检测探针.以反相蛋白质芯片检测为模式,研究了此探针对微量蛋白的检测性能.实验中将不同微量浓度的人IgG固定于醛基修饰玻璃片表面,并加入生物素标记的抗人IgG,结果显示在800fg～100pg含量的微量蛋白检测中此纳米荧光探针具有良好的线性关系,最小蛋白检测量可达100fg.与商品化亲和素偶联cy3荧光探针对比分析发现,本方法制备的荧光探针对蛋白的检测灵敏度可提高8倍,且具有成本低,生物修饰简单等优点.     

具有隔氧功能的Ru（dpp）3（ClO4）2-聚丙烯腈纳米颗粒的制备

选择对氧有敏感响应的4,7-二苯基-1,10-邻菲咯啉钌[Ru(dpp)]为荧光猝灭探针,通过条件优化,制备了粒径100nm左右且包埋有该荧光探针的聚丙烯腈纳米颗粒。研究结果表明,包埋于聚丙烯腈材料中的Ru(dpp)较好保持了原有的荧光特性和稳定性。丙烯腈纳米颗粒在100%氮氧改变的环境中,其荧光强度变化小于2%,显示了较好的隔氧效果。     

点击功能化的叶酸受体靶向荧光纳米探针用于肿瘤细胞成像

采用点击化学偶联法对荧光二氧化硅纳米粒子表面进行叶酸功能化修饰,构建了一种叶酸受体靶向的荧光纳米探针,并成功用于肿瘤细胞的成像研究.首先通过St?ber法制备包裹钌联吡啶的荧光二氧化硅纳米粒子(RSiNPs),然后利用叠氮化硅烷偶联剂(Az-PTES)的水解反应在其表面引入叠氮基团,最后通过点击化学反应将炔丙基叶酸衍生物偶联到粒子表面.利用红外光谱对其偶联前后的叠氮基特征峰(2105 cm-1)进行表征,证实了叶酸功能化的荧光纳米探针(RSiNPs-Folate)已被成功制备.在生理pH条件下,以458 nm为激发波长,RSiNPs-Folate在601 nm处发射较强的红色荧光,且光稳定性较好.细胞成像结果表明,这种叶酸受体靶向的荧光纳米探针能够有效地标记叶酸受体呈阳性的人宫颈癌细胞(HeLa),而叶酸受体呈阴性的人肺癌细胞(A549)未观察到明显的荧光.叶酸竞争性结合实验证明了这种叶酸受体介导的肿瘤细胞成像机制.此探针能够实现混合细胞体系中HeLa细胞的选择性识别与荧光成像.与酰胺化反应偶联叶酸相比,这种点击功能化的纳米探针的合成方法简单、反应条件温和、产率高,可用于不同肿瘤细胞的荧光标记与成像.     

新型铕配合物二氧化硅荧光纳米粒子DPPDA-Eu~(3+)/SiO_2的制备与表征

本文首先合成配位体4,7-二苯基-1,10-菲罗啉-2,9-二羧酸(DPPDA,C_(26)H_(16)N_2O_4)及铕配合物DPPDA-Eu~(3+)((C_(26)H_(16)N_2O_4)_2Eu·15H_2O),然后采用反相微乳液法,通过正硅酸乙酯和3-氨丙基三甲氧基硅烷的共水解、聚合作用成功制备出表面带氨基的二氧化硅包裹铕配合物DPPDA-Eu~(3+)的核壳型荧光纳米颗粒DPPDA-Eu~(3+)/SiO_2。利用透射电子显微镜、荧光光谱、紫外-可见光谱等手段进行表征,并进行了光稳定性、荧光泄露与氨基测定等实验,结果表明所制备的纳米粒子呈规则球状,大小均匀,粒径为80±8nm,具有良好的单分散性和光稳定性,不易发生荧光分子从二氧化硅壳层中泄露,纳米粒子表面带有氨基,可不需要进行表面修饰而直接与生物分子反应。该纳米粒子可望作为一种新型的稀土荧光探针应用于时间分辨荧光免疫分析、生物芯片及生物传感器等。     

细胞自发光探针载基因量子点的制备和成像研究

本研究的目的是验证量子点携带的荧光素酶在细胞内表达后,能否同时激发作为基因载体的量子点,从而构建基于量子点的活细胞自发光探针。利用壳聚糖修饰量子点构建基因运送载体CS-Qdots并对其进行表征;检测CS-Qdots能否被生物发光细胞在宏观距离上激发;并利用CS-Qdots运送真核细胞荧光素酶报告基因质粒pCMV-luciferase至肝癌细胞内,检测虫荧光素酶基因表达后生物发光波长的改变,在体内外成像中证明CS-Qdots是否被生物发光的能量激发。结果显示:制备的CdTe量子点和壳聚糖修饰后的CS-Qdots纳米颗粒在透射电镜下表现为分散均匀的晶体和球菌,CdTe量子点直径约为5nm,CS-Qdots纳米颗粒直径约为20~30nm。动态光散射分析显示,CdTe量子点和CS-Qdots纳米颗粒水合粒子直径分别为102.7±4.4nm和583.0±13.7nm。壳聚糖修饰后的量子点表面出现壳聚糖特有的基团,表面电荷也由-16.31mV转为28.02mV。光谱分析显示量子点具有很宽的吸收光谱和窄而对称的发射光谱。pCMV-luciferase质粒DNA和CS-Qdots结合后,凝胶阻滞实验显示,当CS-Qdots∶pCMV-luciferase10∶1(质量比)时,质粒可与纳米颗粒完全结合。在体外发光细胞激发荧光实验中,CS-Qdots纳米颗粒可以被接种在细胞培养板上的生物发光细胞直接激发。以CS-Qdots作为基因载体运送pCMV-luciferase至肿瘤细胞内表达,在体内外的生物发光成像实验中,均证明成像信号的最大发射波长从生物发光的峰值560nm跃迁至量子点的发射峰值630nm,这一结果间接证实了在细胞内表达的生物发光信号可以直接激发作为基因载体的CS-Qdots纳米颗粒。本研究证实CS-Qdots可被细胞内生物发光能量以非结合的形式激发,载基因量子点纳米颗粒pCMV-luciferase/CS-Qdots可作为活细胞自发荧光成像的探针。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.