pH值响应的共轭聚合物纳米粒子的制备、表征与细胞成像研究

共轭聚合物纳米粒子（CPNs）因其高荧光亮度、低毒性、表面易修饰的特性,近年来在生物材料和生物医药领域备受关注。本论文中我们设计、合成了一种新的pH 值响应共轭聚合物（PFPA）,并通过纳米沉淀方法制备了其纳米粒子。动态光散射实验表明PFPA纳米粒子在水中分散性较好,其粒径约为8 nm。 PFPA纳米粒子的最大吸收峰为379 nm,其摩尔吸光系数为2.1×10⁶ L·mol -1·cm -1;另外该纳米粒子的荧光最大发射峰为422 nm,其荧光量子产率为35%。PFPA纳米粒子在汞灯（100瓦）照射下表现出较好的光稳定性,另外MTT实验表明其具有较低的细胞毒性。该纳米粒子具有pH响应的光学特性,并可以用于活细胞成像。PFPA纳米粒子在癌症诊断、药物与基因传递等方面具有潜在的应用价值。     

手性金纳米团簇:一种新型近红外荧光探针

近红外荧光成像具有低背景荧光干扰、强组织穿透力和对生物机体无光损伤等优点, 因此发展具有良好生物相容性、量子产率高、化学及光稳定性好的水溶性长波段近红外荧光探针成为目前的研究热点. 与有机近红外荧光染料相比, 无机纳米近红外荧光探针因其具有较高的摩尔消光吸光系数和荧光量子产率、抗光漂白能力强、发射光谱集中且可调等特点而备受重视. 采用N-异丁酰基-L(D)-半胱氨酸(N-isobutyryl-L(D)-cysteine, L(D)-NIBC)手性对映异构体作为还原剂和稳定剂一步法直接制备得到两种平均粒径小于2 nm的水溶性手性金纳米团簇(L-NIBC-AuNCs和D-NIBC-AuNCs). CD光谱显示二者在230~360 nm波段的圆二色性完美对称, 荧光光谱显示二者均在900~1000 nm的近红外波段具有较强的荧光发射峰, 且二者的荧光量子产率分别达到6.9% (L-NIBC-AuNCs)和8.2% (D-NIBC-AuNCs), 细胞毒性实验表明这两种手性金纳米团簇均无细胞毒性. 上述结果表明两种手性金纳米团簇不仅符合成为近红外荧光探针的基本要求, 而且还具有不对称光学活性和潜在的手性识别能力等独特性质. 手性金纳米团簇具有成为一类全新的近红外荧光探针的潜力, 为将来实现对特定分子通过手性识别来进行体内近红外荧光示踪和成像提供了全新的思路.     

近红外Ⅰ区喹啉-氟硼二吡咯荧光染料的合成及其在溶酶体内的荧光成像

通过克脑文盖尔缩合反应合成了一种近红外I区的氟硼二吡咯荧光染料(QBOP-lys), QBOP-lys染料是由喹啉-氟硼二吡咯与两个对吗啉苯乙烯结构共轭连接而成,是一种D-A构型的染料,该染料的结构通过了核磁共振以及高分辨质谱表征.在DMSO溶液中,QBOP-lys最大吸收波长为698nm(摩尔消光系数为5.9×10~4L·mol~(-1)·cm~(-1)),最大发射波长位于770 nm, Stokes位移达到73 nm,荧光量子产率为0.18.此外, QBOP-lys还被制备成水溶性的二氧化硅荧光纳米粒子(QBOP-lys/SiO_2),在纯水溶液中最大发射波长位于726 nm,荧光量子产率达到了0.33,使得QBOP-lys无论是在有机溶剂或者是纯水溶剂中都具有非常好的近红外荧光发射特性.另一方面,QBOP-lys还被用于SGC-7901细胞内的溶酶体成像,染料QBOP-lys与溶酶体商业绿色染料Lyso-TrackerGreen的共定位系数高达0.9.此外,染料QBOP-lys在SGC-7901细胞内孵育48h之后,依然能保持很好的荧光成像效果,可被用于长期的溶酶体追踪成像.染料QBOP-lys的体外实验与细胞实验证明, QBOP-lys是一种非常有应用前景的近红外BODIPY染料.     

双光子荧光有机纳米粒子的细胞染色

本文采用具有较大双光子吸收截面的有机分子2,5,2′,5′-(4′-N,N-二苯胺苯乙烯基)联苯(DPA-TSB)(双光子吸收截面δ: 3288 GM, 1 GM=1×10^-50 cm⁴·s·photon^-1·molecule^-1), 通过再沉淀法制备水相分散的纳米粒子. 研究表明, 这种有机双光子纳米粒子可以有效地富集在细胞质中, 对细胞染色显示出良好的荧光成像能力.     

水溶性聚噻吩衍生物的合成、表征及细胞成像

采用FeCl_3氧化聚合制备了一种新型的水溶性聚噻吩衍生物:N,N,N-三甲基-2-(2-{2-[2-(3-噻吩)乙氧基]乙氧基}乙氧基)乙铵溴化物与(4-{[2-(2-{2-[2-(3-噻吩)乙氧基]乙氧基}乙氧基)乙基]氨基甲酰基}苯基)硼酸的无规共聚物(简称PT-2).在水溶液中对其紫外/可见吸收光谱以及荧光发射光谱进行了表征,其最大吸收波长为419 nm,最大发射波长为579 nm,摩尔吸光系数为4. 6×10~3L/(mol·cm),荧光量子产率为12%.动态光散射实验表明其在水溶液中所形成的聚集体平均粒径为234 nm. PT-2在100 W汞灯照射下表现出较好的光稳定性. 3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)实验证明,其对人肺癌A549细胞的毒性较低,细胞成像及共定位分析结果表明PT-2能够富集在溶酶体中,因此,在溶酶体特异性的细胞成像方面具有潜在的应用价值.     

溶酶体靶向吲哚氟硼二吡咯光敏剂的合成、 双光子荧光成像及光动力治疗

通过Knoevenagel缩合反应制备了一个具有溶酶体靶向的近红外光敏剂IMBDP-Lys, 用于双光子荧光成像和光动力治疗. IMBDP-Lys由2个吲哚吗啉功能团连接到氟硼二吡咯(BODIPY)母核的3?位和8?位构筑而成, 是一种重原子诱导的光敏剂. 采用高斯09W理论计算光敏剂S₁态和T₂态能量值相差0.12 eV, 可以有效地发生系间窜越. 在二氯甲烷溶液中, 光敏剂IMBDP-Lys的最大吸收波长为631 nm, 最大发射波长为684 nm. 在 660 nm的光照下, 以亚甲基蓝为参比, 单线态氧量子产率经计算为48.3%. 此外, 含有2个吗啉基团的光敏剂IMBDP-Lys具有良好的生物相容性和精准的靶向能力, 可以快速地进入斑马鱼体内进行双光子荧光成像, 并且与溶酶体绿色染料Lyso-Tracker Green共定位系数为0.95. 溴化噻唑蓝四氮唑(MTT)实验结果表明, 光敏剂具有低的暗毒性(≥85%)和高的光毒性(IC₅₀=0.52 μmol/L). 在660 nm的光照下, 利用活性氧荧光探针2’,7’-二氯二氢荧光素二乙酸酯（DCFH-DA）证明光敏剂可以产生活性氧, 同时吖啶橙/溴化乙锭(AO/EB)染色实验和细胞迁移实验表明产生的活性氧不仅能诱导A549细胞凋亡, 还能有效地抑制肿瘤细胞迁移. 因此, 近红外光敏剂IMBDP-Lys在双光子荧光成像和溶酶体靶向的光动力治疗中具有重要的应用价值.     

新型萘酰亚胺-氟硼二吡咯荧光分子的合成、荧光共振能量转移及细胞成像

通过Click反应合成了萘酰亚胺-氟硼二吡咯复合结构荧光分子1-(2-(4-(1,3,5,7-四甲基氟硼二吡咯基)苯氧基)乙基)-4-(4-N-正丁基-1,8-萘酰亚胺)-1,2,3-三唑(NP-BODIPY),化合物结构经核磁共振氢谱、核磁共振碳谱以及高分辨质谱确征.NP-BODIPY存在从萘酰亚胺能量给体到氟硼二吡咯能量受体之间的分子内荧光共振能量转移.制备了负载萘酰亚胺-氟硼二吡咯荧光染料NP-BODIPY的二氧化硅荧光纳米粒子NP-BODIPY/Si O_2,粒径为50 nm,测定了NP-BODIPY的紫外可见吸收及荧光光谱.NP-BODIPY的固体在暗室中紫外灯下呈紫红色荧光;NP-BODIPY的THF溶液呈明亮的绿色荧光,荧光发射在430和510 nm呈双峰结构,荧光量子产率为0.67,紫外吸收位于366和500 nm;NP-BODIPY在含水量为80%H_2O/THF混合溶液中的荧光较强,荧光量子产率为0.39,最大荧光峰位于510 nm.将其与人乳腺癌细胞(MCF-7)共同孵化,荧光染料纳米粒子进入MCF-7细胞内并清晰成像.NP-BODIPY/Si O_2荧光纳米粒子亲水性好,尺寸可控,细胞毒性低,生物相容性优,可广泛应用于生物标记及荧光成像.     

超小荧光二硫化钨量子点的水热合成及细胞成像应用

以钨酸钠和半胱氨酸为原料, 采用水热法一步合成了具有超小粒径(约2 nm)的二硫化钨荧光量子点(WS₂ QDs). 利用透射电子显微镜(TEM)、 荧光光谱、 X射线光电子能谱(XPS)、 红外光谱(FTIR)和X射线衍射光谱(XRD)对其进行了表征, 并考察了其稳定性和细胞毒性. 结果表明, 制备的WS₂ QDs具有水溶性好、 稳定性高和细胞毒性低的优点. 将此WS₂ QDs用于人乳腺癌细胞(MCF-7)的成像, 并通过溶酶体荧光探针进行共定位, 发现此WS₂ QDs可能借助溶酶体进入细胞内.     

基于类芬顿反应的Mn3O4/DOX@Lip纳米递药体系的构建及应用

利用肿瘤微环境与普通组织的差异, 我们设计了一种基于类芬顿反应(Fenton-like reaction)的微环境响应的纳米递药体系(Mn₃O₄/DOX@Lip). 首先利用热分解法制备得到锰的氧化物(Mn₃O₄)纳米粒子, 基于化疗药物阿霉素(DOX)与Mn原子的配位作用, 该纳米粒子可以负载并递送DOX, 其最外层包裹的酸敏脂质体能有效防止药物在递送过程中的泄露. 在肿瘤细胞的弱酸性和高浓度谷胱甘肽的微环境中, 脂质体膜破裂, 其中的Mn₃O₄纳米粒子被谷胱甘肽还原、分解, 并释放出DOX. 共聚焦成像结果表明, MCF-7细胞与Mn₃O₄/DOX@Lip共孵育后, 细胞中活性氧探针的荧光显著增加, 表明该递药体系可以通过下调细胞中的谷胱甘肽的含量引发细胞中的活性氧含量增加. 噻唑蓝(MTT)和流式细胞实验结果表明, 相比于单一的化疗药物, Mn₃O₄/DOX@Lip的细胞毒性增强, 这可能归因于还原产物Mn²⁺触发了类芬顿反应从而将细胞中内源性的H₂O₂转化为毒性更强的•OH. 氧化活性物质介导的细胞凋亡与化疗药物的细胞毒性相互促进, 增强了对细胞的凋亡能力. 本体系利用外源性的物质激发内源性的细胞毒性, 增强了化疗药物的治疗效果, 为肿瘤治疗提供了新的研究策略.     

高效近红外聚集诱导发光纳米粒子用于生物成像的研究

基于荧光共振能量转移机理（FRET）,利用两亲性聚合物Pluronic F-127共包覆两种聚集诱导发光（Aggregation-induced Emission,AIE）材料TPABDFN和TPE-Me,制备了高效近红外发射TPABDFN/TPE-Me@F127纳米粒子.实验表明,这种聚合物纳米粒子具有很大的斯托克斯位移和较高的荧光量子效率,很好的单分散性、稳定性,以及较好的生物相容性和低的细胞毒性,对HepG2细胞进行荧光生物成像,得到很好的细胞成像效果.     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.