用于细胞成像的双氰基二苯代乙烯衍生物双光子荧光银离子探针

双光子荧光显微成像兼具诸如近红外激发、暗场成像、避免荧光漂白和光致毒、定靶激发、高横向分辨率与纵向分辨率、降低生物组织吸光系数及降低组织自发荧光干扰等特点,显著地优于单光子荧光显微成像,为生命科学研究提供了更为便利的工具.因此双光子荧光探针适合于生物检测与成像.制备了衍生于二苯代乙烯的双光子荧光银离子探针,此探针以拥有异常大的双光子吸收截面(6TPA)的4-甲基-2,5-二氰基-4'-氨基二苯乙烯(DCS)作为双光子荧光母体,以6-芳基-3,9-二硫-6-氮杂癸烷(TAU)为Ag+配体.探针显示了大的δTPA(在MeCN中,950 GM)、对银离子有高的灵敏性与选择性、强的双光子荧光(790 nm激光激发时).探针的络合常数为IgK=5.76±0.05.探针能选择性地检测和成像活细胞中的游离Ag+,可用于细胞中微量Ag+的分析检测与成像.此探针为开发理想的双光子荧光探针提供了可供借鉴的平台.     

肿瘤特异性多肽探针及其在生物成像中的应用

肿瘤是由细胞、细胞外基质及微环境等多因素组成的复杂系统,不同因素在肿瘤的发生和发展中发挥关键作用.肿瘤细胞、细胞外基质及微环境的特异性分析对于肿瘤的精准诊断和靶向治疗至关重要.多肽探针具有特异性高、生物相容性好、组织穿透能力强和易于制备等优点,已被广泛用于肿瘤的特异性成像研究.本文综述了多肽探针对肿瘤细胞、免疫细胞等细胞靶点的特异性成像;并介绍了以胶原蛋白、纤维蛋白等外基质蛋白为靶点的肿瘤特异性多肽探针的成像研究.本文还总结了对肿瘤微环境中弱酸性、高酶活性等因素响应的肿瘤特异性多肽探针及其生物成像应用.最后,本文总结并讨论了肿瘤特异性多肽探针所面临的挑战与机遇,展望了其在肿瘤精准诊断和个性化治疗领域的前景.     

γ-谷氨酰转移酶近红外比率型荧光探针的设计与成像

γ-谷氨酰转肽酶(GGT)在诸多肿瘤组织中高表达,是一种重要的肿瘤标志物,对其活性的准确检测有助于相关疾病的早期诊断与治疗.本文将谷胱甘肽(GSH)共价修饰于七甲川花菁染料上作为GGT的酶切位点,研制了一例可用于GGT活性检测的近红外比率型荧光探针(Cy-GGT).该探针具有良好的水溶性,向其溶液中加入GGT,荧光发射波长由808 nm蓝移至616 nm (蓝移192 nm).较大的发射位移可避免两个信号之间的串扰,提高检测的准确性.实验表明,探针Cy-GGT可特异性检测GGT活性,检测限为0.02 mU/mL,并可用于活细胞和动物体中GGT的活性检测和荧光成像,能够区分肿瘤细胞与正常细胞,有望在相关疾病的早期诊断与治疗中发挥积极作用.     

叶酸受体介导的肿瘤靶向光学成像技术

叶酸受体(FR)在肿瘤细胞中都有过度表达,而在正常组织中保守表达,利用叶酸受体与叶酸及其类似物高亲合力结合的特性,将叶酸偶联荧光探针输送到肿瘤组织,从而实现肿瘤组织的特异性靶向光学成像。本文阐述了叶酸荧光探针的结构及其用于标记肿瘤细胞的作用机制,介绍了近十年来叶酸受体介导的肿瘤靶向光学成像技术,例如有机荧光染料,染料掺杂纳米颗粒,量子点,磁性纳米微粒以及多功能纳米粒子等在肿瘤靶向成像中的研究及应用进展,指出了当前研究中的主要发展方向和仍需解决的问题。     

用于糖链抗原CA19-9实时动态活检的免疫双光子荧光标记试剂盒

采用双光子荧光标记探针LP制备了免疫双光子荧光抗体LP-Ab,以特异性识别肿瘤标志物CA19-9(Ag)形成抗原-抗体复合物(LP-Ab·Ag),基于双光子诱导荧光机制用近红外激光(740 nm)激发LP-Ab·Ag,利用LP-Ab·Ag的双光子荧光实现了CA19-9的高清晰度、高灵敏度及高分辨率的量化检测和实时动态成像,并制成用于糖链抗原CA19-9检测的简单便捷的双光子荧光标记试剂盒.     

缺氧响应荧光探针的成像及治疗应用

由于肿瘤内部细胞远离血管, 其氧气消耗量远远超出血液供应量, 因此容易导致肿瘤缺氧. 肿瘤缺氧会引发肿瘤扩散加速、 诱导某些基因过表达及产生药物抗药性等问题. 基于此, 发展性能优异的缺氧响应荧光探针对肿瘤的诊断和治疗具有重要意义. 本文对缺氧响应荧光探针在成像及治疗方面的应用进展进行了综合评述, 介绍了硝基、 偶氮键和醌3种常用的缺氧响应基团, 并探讨了它们在缺氧微环境下的识别机理; 介绍了缺氧响应荧光探针的构建及其在生物成像方面的最新研究成果; 总结了缺氧响应荧光探针在基因治疗、 光动力学治疗、 化学治疗及协同治疗方面的研究进展; 展望了缺氧响应荧光探针在临床诊断和治疗方面的应用前景.     

HA-AuNPs/FDF用于透明质酸酶的高灵敏检测、肿瘤靶向细胞荧光成像和光疗

本工作构建了一种新型复合纳米诊疗剂HA-AuNPs/FDF,用于透明质酸酶(HAase)的高灵敏荧光检测、肿瘤靶向荧光成像和光动力/光热协同治疗.吡咯并吡咯二酮基共轭小分子(FDF)与肿瘤靶向生物分子透明质酸(HA)功能化的金纳米粒子(HA-AuNPs)通过静电作用自组装形成HA-Au NPs/FDF. FDF在近红外光激发下产生较强的荧光, HA-AuNPs会通过荧光共振能量转移效应(FRET)猝灭FDF的荧光.然而,肿瘤细胞中过表达的透明质酸酶(HAase)能使HA逐渐降解, FDF被释放,从而荧光逐渐恢复. HA-AuNPs/FDF的荧光恢复程度与HAase的浓度有很好的线性关系,可用于快速定量检测HAase.而且, HA-AuNPs/FDF作为透明质酸酶激活的荧光探针成功地用于人宫颈癌肿瘤HeLa细胞的靶向荧光成像,细胞实验结果证实它能通过光动力/光热协同治疗有效抑制HeLa细胞的增殖.该体系为实现精准高效的肿瘤诊疗拓展了思路.     

醌氧化还原酶响应型光声探针的合成及其对乳腺癌的成像

醌氧化还原酶(NQO1)是生物体内的一种双电子还原反应的专性催化还原酶. 在一些疾病如乳腺癌中NQO1过度表达, 因此NQO1可作为生物标志物以观察乳腺癌肿瘤的产生和发展. 目前已有一些文献报导用于NQO1检测和荧光成像的荧光探针, 但大部分这些探针具有吸收波长较短、背景干扰较强、组织穿透深度较低等不足. 为克服荧光探针成像的上述缺陷, 我们构建出一种具有推拉电子结构的可对NQO1响应的新型近红外光声探针TPA-X-Q. 实验结果表明, 该探针可在生物体内和体外对NQO1进行专一性的增强型光声检测和成像, 并可提供高分辨率的实时光声信号图像. 此外, 这种新型的光声探针能够成功应用于乳腺癌小鼠模型, 对乳腺癌肿瘤中过量表达的NQO1进行灵敏准确的光声检测与成像, 借助多光谱光声断层扫描技术(MSOT)的三维光声图像重建功能, 可实现肿瘤病灶区域的定位.     

新型双光子荧光探针用于高灵敏检测硝基还原酶及细胞成像

以2-乙酰基-6-甲氨基萘为荧光团,对硝基氯甲酸苄酯为识别域,设计合成一种新型双光子荧光探针NNTR。基于单光子和双光子模式考察了NNTR探针的光学特性及其对硝基还原酶(NTR)的荧光响应,发现在NADH催化下,NNTR可与NTR(NTR)反应,5 min后,在单光子激发模式下,510 nm处的发射光强度增加了约350倍,而在双光子激发模式下,810 nm处的发射光强度增加了约500倍,活性截面积可达66 GM(1 GM=1×10~(-50)cm~4·s/photon)。将NNTR探针用于NTR检测,检出限低至22 ng/mL,且具有反应速度快、选择性高、光学稳定性好等特点。考察了探针对HeLa的细胞毒性,并以盖玻片诱导缺氧法使HeLa细胞缺氧,促使NTR过表达,实现了NNTR探针对HeLa活细胞中NTR的成像分析。     

双光子荧光探针研究及其应用*

双光子荧光显微成像兼具诸如近红外激发、暗场成像、避免荧光漂白和光致毒、定靶激发、高横向分辨率与纵向分辨率、降低生物组织吸光系数及降低组织自发荧光干扰等特点而显著地优于单光子荧光显微成像,为生命科学研究提供了更为锐利的工具。而用于像离子的含量及其对生理的影响、离子参与的生理活动机制、离子与分子的作用、特定分子的分布及其相互作用等方面研究的双光子荧光探针,是实现成像的关键。双光子荧光探针的研究旨在促进双光子荧光显微镜应用的发展,促进生命科学、医学科学的快速发展,同时也带动双光子荧光探针所隶属的化学这一学科的发展。因此对双光子荧光探针的研究具有重要的理论和实践意义。该文综述了双光子荧光显微成像的优点、双光子荧光探针设计的原理及双光子荧光探针在离子分析方面的应用,并展望了这类荧光探针的发展趋势与应用前景。     

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.     

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.     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.