基于富G序列的无标记荧光传感器检测单链核酸

具有特定构象的富G序列（如G-四链体和G-三链体）与荧光染料相互作用可有效增强其荧光信号强度，被广泛应用于构建无标记荧光生物传感。本研究以硫磺素T(Thioflavin T, ThT)为荧光染料，构建了两种基于富G序列的无标记荧光传感器，用于检测阿尔兹海默病标志物β-淀粉样蛋白（β-Amyloid protein, Aβ）的基因序列。实验结果表明，分子发夹茎长为4个碱基时，富G序列以G-三链体的结构存在，以此构建的G-三链体传感器的输出信号随Aβ基因浓度增加而降低，线性检测范围为1～100 nmol/L，检出限为0.3 nmol/L(S/N=3)。分子发夹茎长为8个碱基且5′端添加碱基AATT时，其与Aβ基因结合后，富G序列多以G-四链体结构存在，以此构建的G-四链体传感器的输出信号随Aβ基因浓度增加而增强，线性检测范围为0.1～100 nmol/L，检出限为0.04 nmol/L (S/N=3)。两种传感器制备过程相似但检测原理不同，为富G序列的深入研究与应用提供了参考，同时为单链核酸的无标记荧光检测提供了新的思路。     

基于G-四链体结构多态性的核酸纳米技术

G-四链体是由富G核酸形成的独特四链螺旋结构,区别于遵循A-T、G-C碱基互补配对原则形成的传统Watson-Crick双链结构.基于G-四链体的特异分子识别特性,能够引导纳米粒子的有序组装、赋予纳米器件以刺激一响应功能,使得核酸纳米技术领域的内容更丰富多样.本文介绍了G-四链体的结构多态性,从纳米材料组装和纳米器件设...     

带有羧酸基侧臂的十元环大环三胺衍生物及其金属配合物的合成和结构表征

合成了侧壁带有羧酸基的十元环大环三胺衍生物配体1,4,7-三氮杂环癸烷-N,N′N″-三羧酸(L)及它的4种过渡金属配合物[ML]·1/2[M(H2O)6]·[ClO4]·nH2O(M=Co2+,Cu2+,Ni2+,Zn2+),利用元素分析,红外光谱以及热重分析等手段对它们的结构进行了表征,并测定了配合物[NiL]·1/2[Ni(H2O)6]·[ClO4]·3H2O(1)的晶体结构。结果表明这4种配合物具有类似的结构。     

靶向抑制拓扑异构酶和端粒酶的钌配合物研究进展

金属配合物抗肿瘤研究,尤其是铂类药物,已取得了相对令人瞩目的成功,但同时也面临着包括耐药性和毒副作用等诸多问题。近年来钌配合物作为新的抗癌药物引起了人们的注意。在非铂系药物中,金钌配合物;拓扑异构酶;G-四链体;端粒酶属钌配合物是最有前途的抗癌药物之一,国际上普遍认为钌和钌的配合物属于低毒性,容易吸收并在体内很快排泄。本文将着重介绍钌配合物与DNA结合后进一步引发的细胞内核酶活性抑制研究,从新的角度来诠释钌配合物的抗肿瘤研究最新进展。     

靶向抑制拓扑异构酶和端粒酶的钌配合物研究进展

金属配合物抗肿瘤研究,尤其是铂类药物,已取得了相对令人瞩目的成功,但同时也面临着包括耐药性和毒副作用等诸多问题。近年来钌配合物作为新的抗癌药物引起了人们的注意。在非铂系药物中,金属钌配合物是最有前途的抗癌药物之一,国际上普遍认为钌和钌的配合物属于低毒性,容易吸收并在体内很快排泄。本文将着重介绍钌配合物与DNA结合后进一步引发的细胞内核酶活性抑制研究,从新的角度来诠释钌配合物的抗肿瘤研究最新进展。     

基于核酸修饰新策略的抗肿瘤铂配合物设计

肿瘤已成为严重威胁人类健康的重大疾病之一。以顺铂为首的铂类抗肿瘤药物一直是化疗首选药物。但是长期用药导致的一系列的毒副作用如肾毒性、耳毒性和耐药性等极大地限制了铂类配合物的发展与应用。本文针对目前铂类药物所处形势重点综述了新一代铂类药物的设计研发方法：（1）研发具有新颖结构的铂类药物,例如经过改造的反式铂类配合物、多核铂类配合物、Pt（Ⅳ）配合物等;（2）发展新的抗肿瘤靶点,例如以G-四螺旋DNA（G4-DNA）为靶点,为寻找更有效的铂类抗肿瘤药物提供新的思路。同时通过列举最新研究成果,分析药物的抗肿瘤机理及在克服顺铂耐药性机理方面的研究进展,提出铂类药物的设计研发方法,让读者了解铂类抗肿瘤药物的发展历程和未来的发展趋势。     

1,4,7-三氮杂环癸烷过渡金属配合物的合成与结构表征

以十元环大环三胺配体1,4,7-三氮杂环癸烷(tacd)为主配体,分别与钴、镍、铜和锌的顺丁烯二酸盐和己二酸盐进行反应,得到了8种含有双大环的单核配合物,利用元素分析,红外光谱以及热重分析等手段对它们的结构进行了表征.结果表明这八种配合物具有类似的配位结构.     

核酸G-四链体的识别、复合物结构与细胞内探测的研究进展

富含鸟嘌呤的DNA或RNA序列可以折叠成非典型G-四链体二级结构. G-四链体结构丰富多样,在生物体内动态存在,参与了转录、复制、基因组稳定性和表观遗传调控等关键的基因组功能,与癌症生物学密切相关. G-四链体的结构与功能机制研究促进了以G-四链体为靶点的肿瘤治疗干预.本文综合评述了核酸G-四链体的特异性识别、细胞内探测及生物学功能的调控,总结了识别靶向G-四链体的小分子及复合物结构的研究进展,讨论了以G-四链体为靶点的靶向干预及疾病治疗的可能性,最后展望了G-四链体未来研究所面临的挑战与机遇.     

以G-四链体为靶点的小分子端粒酶抑制剂研究进展

富含鸟嘌呤碱基的DNA序列能够通过鸟嘌呤环的互联作用形成四链螺旋结构,这种结构被称为G-四链体。G-四链体由于能够抑制端粒酶的活性而成为抗肿瘤药物的新靶点,能促使G-四链体形成或稳定该结构的物质则可能对癌症有潜在的治疗意义。本文对以G-四链体为靶点的小分子端粒酶抑制剂的研究进行了综述。     

三脚架结构化合物及其配合物研究进展

本文按三脚架结构化合物中心部分构成的不同。分四类对配体及其配合物的结构,性能进行了介绍。（1）以环为中心的三脚架结构化合物;（2）以氮原子为中心的三脚架结构化合物;（3）以碳原子为中心的三脚架结构化合物;（4）以硼原子及磷原子为中心的三脚架结构化合物。     

Site-directed cleavage of DNA by an oligonucleotide conjugate with o-bromobenzoic acid in the presence of copper ions

Site-directed cleavage of single- and double-stranded DNAs by an oligonucleotide conjugate with 5-[N-(3-aminopropyl)sulfamoyl]-2-bromobenzoic acid was investigated. When forming duplex complexes with a single-stranded DNA and triplex complexes with a double-stranded DNA, this conjugate cleaves DNA near the binding site in the presence of copper ions and free o-bromobenzoic acid. The efficacy and specificity of DNA cleavage by this conjugate and other oligonucleotide conjugates bearing tetracarboxyphthalocyanine Co^II and bleomycin A5 as reactive groups were compared.     

A DNA nanomachine based on rolling circle amplification-bridged two-stage exonuclease III-assisted recycling strategy for label-free multi-amplified biosensing of nucleic acid

An autonomous DNA nanomachine based on rolling circle amplification (RCA)-bridged two-stage exonuclease III (Exo III)-induced recycling amplification (Exo III-RCA-Exo III) was developed for label-free and highly sensitive homogeneous multi-amplified detection of DNA combined with sensitive fluorescence detection technique. According to the configuration, the analysis of DNA is accomplished by recognizing the target to a unlabeled molecular beacon (UMB) that integrates target-binding and signal transducer within one multifunctional design, followed by the target-binding of UMB in duplex DNA removed stepwise by Exo III accompanied by the releasing of target DNA for the successive hybridization and cleavage process and autonomous generation of the primer that initiate RCA process with a rational designed padlock DNA. The RCA products containing thousands of repeated catalytic sequences catalytically hybridize with a hairpin reporter probe that includes a “caged” inactive G-quadruplex sequence (HGP) and were then detected by Exo III-assisted recycling amplification, liberating the active G-quadruplex and generating remarkable ZnPPIX/G-quadruplex fluorescence signals with the help of zinc(II)-protoporphyrin IX (ZnPPIX). The proposed strategy showed a wide dynamic range over 7 orders of magnitude with a low limit of detection of 0.51 aM. In addition, this designed protocol can discriminate mismatched DNA from perfectly matched target DNA, and holds a great potential for early diagnosis in gene-related diseases.     

An unexpected fluorescent probe for G-quadruplex DNA based on a nitro-substituted ruthenium (II) complex

The detection of G-quadruplex is of major interest. Nitro-substituted ruthenium (II) complexes have attracted much attention due to fluorescent sensitivity to environment change. We report here a new nitro-substituted ruthenium (II) complex, [Ru (phen)₂(hnoip)]²⁺ ( 1) (hnoip = 2-(2-hydroxyl-5-nitrophenyl)imidazo[4,5-f][1,10-phenanthroline]), which displays distinct fluorescent properties in aqueous solution and non-aqueous solvents. This complex exhibits large fluorescence enhancement after binding with G-quadruplex DNA, and displays good fluorescent selectivity over other DNAs. The limit of detection is 6 nm for 22AG in Na⁺ and 43 nm for 22AG in K⁺, respectively. The results demonstrated that nitro-substituted ruthenium (II) complexes can be utilized to design as G-quadruplex fluorescent probes by protection of the nitro group on the complex from water.     

第一过渡系列金属元素单核水氧化催化剂的最新进展

水的氧化是光合作用的重要步骤,其提供用于二氧化碳固定的电子和质子,以及生物圈所必需的氧气.在将太阳能转换为化学能的人工光合作用中,设计合成高效稳定的水氧化催化剂是研究的关键.目前的催化体系主要是基于钌和铱等贵金属的金属氧化物纳米颗粒和多核金属配合物.基于钌和铱的单核催化体系近年来也得到了广泛的发展.最近几年,第一过渡系列金属元素单核水氧化催化剂快速得到重视.作为配合物中心原子,它们不仅具有丰富的氧化态,而且因相对充足的蕴藏和较低的开采冶炼成本,其具有钌和铱等贵金属不可比拟的重大优势和广阔的应用前景.本文总结了近几年第一过渡系列金属元素单核水氧化催化剂的进展,并在此基础上,简单讨论了氧—氧键的生成,为进一步设计新颖、具有高催化效率和高稳定性的单核水氧化催化剂提供了理论依据.     

Microgravimetric flow analysis of nucleic acid based on adsorption of nanoparticle-bioconjugate

A novel nanoparticle-bioconjugate has been prepared by specific hybridization of the target with complementary thiol-labeled and nanoparticle-labeled probes. The rapid adsorption of the nanoparticle-bioconjugate onto a gold surface via a thiol-gold reaction was monitored in real-time using a quartz crystal microbalance, and used to perform microgravimetric flow analysis of nucleic acid for the first time. This innovative assay is highly reproducible and sensitive, and shows great promise for clinical applications.     

Determination of nucleic acid based on increased resonance light-scattering of fluorinated surfactants

Two novel surfactants perfluoroalkanesulfonyl quaternary ammonium iodides (FC134) and potassium perfluorooctanesulfonate (FC95) were successfully used as new probes for detection of DNA by resonance light-scattering (RLS) technique. Resonance light-scattering characteristics of the binding of fluorinated surfactants FC134 and FC95 to calf thymus nucleic acid (ctDNA) were studied. After DNA was added, aggregation of FC134 on the molecular surface of DNA in the pH 3.0-6.0 and aggregation of FC95 on the surface of DNA in the pH 3.5-6.0 occurred, both of which resulted in an enhanced resonance light-scattering peak at 370 nm. The intensity of resonance light-scattering was found to be proportional to the concentration of DNA. The determination limits were 3.5 and 20.0 μg L⁻¹, respectively. UV-vis spectra and IR-spectra both proved the binding of fluorinated surfactants to DNA.     

Adaptive recognition of small molecules by nucleic acid aptamers through a label-free approach

We report a novel label-free method for the investigation of the adaptive recognition of small molecules by nucleic acid aptamers using capillary electrophoresis analysis. Cocaine and argininamide were chosen as model molecules, and the two corresponding DNA aptamers were used. These single-strand DNAs folded into their specific secondary structures, which were mainly responsible for the binding of the target molecules with high affinity and specificity. For molecular recognition, the nucleic acid structures then underwent additional conformational changes, while keeping the target molecules stabilized by intermolecular hydrogen bonds. The intrinsic chemical and physical properties of the target molecules enabled them to act as indicators for adaptive binding. Thus any labeling or modification of the aptamers or target molecules were made obsolete. This label-free method for aptamer-based molecular recognition was also successfully applied to biological fluids and therefore indicates that this approach is a promising tool for bioanalysis.     

Recent progress in quantitative analysis of DNA adducts of nephrotoxin aristolochic acid

Aristolochic acid (AA), a mixture of structure-related nitrophenanthrene carboxylic acid derivatives derived from Aristolochia spp, is associated with nephrotoxin and carcinogen. AA-DNA adducts induced by reductive metabolic activation of AA were detected in tissues of animals and in patients exposed to AA. The DNA adducts were generally used as biomarkers in toxicological study of AA. In this short review, quantitative analysis of AA-DNA adducts in various in vitro and in vivo systems by using 32P-postlabe...