氨基甲酸酯型石胆酸分子裂缝的微波合成

利用人工受体与适当底物间的分子识别以建立仿生模型的研究已成为生物有机化学的前沿领域之一。作为一类新型的人工受体,分子裂缝近年来在分子识别、生物传感、外消旋体的拆分、分子器件等领域引起越来越多的关注[1-3]。胆甾因其具有刚性的凹面结构和固有的手性,是构筑钳形人工     

新型鹅去氧胆酸分子裂缝的设计合成

分子识别是生物体系的基本特征,并在生命活动中起中心作用。生物酶高效专一地催化生化反应,抗体与抗原的结合,蛋白质分子与DNA序列的相互作用等都源于精确的分子识别[1,2]。利用合成的人工受体与适当底物之间的分子识别以建立仿生仿酶模型的研究,已成为生物有机化学前沿富有挑战性的领域。分子裂缝作为一类新型的人工受体,以其灵活的结构以及易于将功能团聚集在受体与底物结合的活性部位上等优点,引起了人们的广泛关注[3-5]。胆甾因其具有刚性的凹面结构和天然的手性,是构筑分子裂缝人工受体的理想结构单元。我们曾报道3α-OH和7α-OH同…     

基于分子钳化合物的手性识别研究进展

手性是自然界中广泛存在的现象,设计合成新型人工受体模拟生物体内的分子识别已经成为生物有机化学和超分子化学等领域富于挑战性的课题之一.分子钳类人工受体结构易于修饰,在手性识别和检测中具有广泛的应用前景,本文对近年来合成的分子钳人工受体以及应用光谱、色谱和质谱等检测手段对其手性识别性能的研究进行了总结,并对分子钳人工受体的发展前景作出了展望.     

分子钳人工受体研究进展

分子识别是生物体系的基本特征, 并在生命活动中起中心作用. 利用合成的人工受体与适当底物间的分子识别以建立化学模型或化学仿生体系对生命过程中的分子识别现象进行模拟研究是生物有机化学和超分子化学前沿富于挑战的课题之一. 按照不同的隔离基, 综述了分子钳人工受体的研究进展.     

胆甾类人工受体的分子识别研究进展

人工受体分子识别研究是生物有机化学的前沿领域之一。综述了近年来以胆甾 为构筑单元建造的人工受体在分子识别方面的研究进展。     

单手性臂脱氧胆酸分子钳的设计与微波合成

分子钳人工受体的研究已成为生物有机化学和超分子化学前沿领域的研究热点.钳型结构受体以其灵活的结构及易于将裂穴内功能团汇聚在受体与底物结合的活性部位上等特点,对于实现主客体形状、大小和功能互补特别有效.     

人工分子机器:分子尺度运动的精准化与可视化

分子机器在自然界至关重要,其在生物过程中执行了大量复杂的功能,从而实现不同尺度的动态行为调控.受生物系统的启发,科学家致力于研究人工分子机器在分子尺度下的精准构筑和定向运动,并通过层级组装实现信号传递和功能放大,从而推动动态智能材料的设计发展.但如何利用新方法精准构筑复杂的人工分子机器,如何将分子尺度的运动动态进行“可视化”,以及如何在生命科学研究中发挥其功能,一直是分子机器领域的研究热点.本文基于本课题组的工作,系统介绍了人工分子机器在分子尺度的精准结构构筑、信号输出以及其在跨膜运输方面的研究.最后总结了该领域在多尺度精细化和功能化方面的挑战,并展望了分子机器在宏观智能材料领域的发展前景.     

新型脱氧胆酸钳形阴离子受体的设计合成及其对阴离子的识别性能研究

具有对阴离子选择性识别的人工受体的设计合成是生物有机化学和超分子化学前沿富于挑战性的领域之一[1].在许多识别阴离子的人工受体化合物中,脲和硫脲衍生物是重要的中性受体化合物之一.     

具有聚集诱导发光性质的近红外荧光染料

聚集诱导发光(AIE)现象的发现为解决传统有机荧光分子在高浓度和聚集形态下存在的荧光猝灭问题提供了最佳方案,并实现了在光电器件、化学传感、生物成像和靶向治疗等众多领域的广泛应用.随着对AIE 发光机理研究的不断深入,AIE 分子体系得到了极大的扩展.其中,一类具有给体-受体结构的AIE分子能够显著降低分子能隙,使发光分...     

聚集诱导发光高分子在光学诊疗应用中的研究进展

高分子因其优异的光学特性、良好的生物相容性和分子结构易于调控等优势,在光学诊疗领域表现出巨大应用潜力.然而,传统荧光分子的聚集导致荧光淬灭现象限制了其生物应用.聚集诱导发光(AIE)分子因其聚集态高效发光的优势而备受关注.本文从AIE高分子的构建出发,重点介绍了D-A型共轭聚合物的构建策略、构-效关系以及相对于小分子的性能和应用优势,并从生物成像、肿瘤诊疗和抗菌三个方面总结了AIE高分子在光学诊疗领域的最新研究进展.生物成像方面主要总结了NIR-Ⅱ区AIE高分子在深部组织高分辨率荧光成像中的应用;肿瘤诊疗方面主要介绍了AIE高分子在光动力治疗、光热治疗及联合治疗中的应用;以及介绍了AIE高分子在细菌感染光动力治疗中的应用.最后对AIE高分子在光学诊疗领域的未来发展前景进行了展望.     

Advances in Artificial Layers for Stable Lithium Metal Anodes

Lithium (Li) metal is considered as the most promising anode material for rechargeable high-energy batteries. Nevertheless, the practical implement of Li anodes is significantly hindered by the growth of Li dendrites, which can cause severe safety issues. To inhibit the formation of Li dendrites, coating an artificial layer on the Li metal anode has been shown to be a facile and effective approach. This review mainly focuses on recent advances in artificial layers for stable Li metal anodes. It summarizes the progress in this area and discusses the different types of artificial layers according to their mechanisms for Li dendrite inhibition, including regulation of uniform deposition of Li metal and suppression of Li dendrite growth. By doing this, it is hoped that this contribution will provide instructional guidance for the future design of new artificial layers.     

The place and the role of chemical analysis in process control

Summary For the recognition, control and regulation of natural or artificial dynamic systems, the adjustment of the parameters of the investigated system is indispensable as are those of the measurements used. Calculations are introduced here by which the controllability of the sulphonation process during the production of dodecyl-benzene sulphonate can be predicted using analytical procedures.Presented at the 33rd IUPAC Congress, Budapest, August 17–22, 1991.     

Cross‐Regulation of an Artificial Metalloenzyme

Cross‐regulation of complex biochemical reaction networks is an essential feature of living systems. In a biomimetic spirit, we report on our efforts to program the temporal activation of an artificial metalloenzyme via cross‐regulation by a natural enzyme. In the presence of urea, urease slowly releases ammonia that reversibly inhibits an artificial transfer hydrogenase. Addition of an acid, which acts as fuel, allows to maintain the system out of equilibrium.     

Two‐Step Synthesis of Complex Artificial Macrocyclic Compounds

The design and synthesis of head‐to‐tail linked artificial macrocycles using the Ugi‐reaction has been developed. This synthetic approach of just two steps is unprecedented, short, efficient and works over a wide range of medium (8–11) and macrocyclic (≥12) loop sizes. The substrate scope and functional group tolerance is exceptional. Using this approach, we have synthesized 39 novel macrocycles by two or even one single synthetic operation. The properties of our macrocycles are discussed with respect to their potential to bind to biological targets that are not druggable by conventional, drug‐like compounds. As an application of these artificial macrocycles we highlight potent p53–MDM2 antagonism.     

基于核酶开关的哺乳细胞内硫胺素焦磷酸荧光生物传感器的建立

硫胺素焦磷酸(Thiamine pyrophosphate,TPP)是维生素B1在细胞内的主要活性形式,也是糖、脂肪酸和氨基酸氧化代谢中重要的辅助因子.在细胞内,利用TPP适配体与天然核酶组装成的人工核酶开关调节靶基因表达,目前仅局限于原核、真菌或植物细胞.本实验将原核生物中筛选的“Switch-on”与“Switch-off"的两种类型的TPP核酶开关,运用重叠延伸PCR的方法构建于增强绿色荧光蛋白(EGFP)报告基因的3'非翻译区(UTR),转染人胚肾上皮细胞(HEK293),通过荧光显微镜和流式细胞仪分析,观察了不同浓度TPP对EGFP表达能力的调控.结果表明,构建的两种“Switch-on”和一种“Switch-off”核酶开关均表现出明显的TPP浓度依赖性,且具有良好的特异性,在150 μmol/L TPP时分别将EGFP的荧光强度提高3.1倍、1.9倍和降低2.3倍.这种构建通过TPP与核酶开关中其适配体的特异性作用直接将TPP浓度的变化转化为报告基因表达的改变,利于通过荧光检测方法实现对哺乳活细胞内代谢物或因子的无标记、无损伤、可视、高效的检测.     

A Multi-Touch Plate Based on Lamb Wave Absorption

In this paper, the A0 Lamb wave propagating in a thin finite copper plate is investigated to design a new multi-touch tactile instrument, which could localize one or several fingers. The position of index is localized by identifying the absorption signals of Lamb waves when it is in contact with the plate. Statistic models are used to improve the robustness of this interface. An artificial silicone finger is fabricated in the calibration procedure. The multi-touch (two fingers or more) applications using this plate is also presented.     

Uni-, bi-, and tri-directional wetting caused by nanostructures with anisotropic surface energies

Wetting is a pervasive phenomenon that governs many natural and artificial processes. Asymmetric wetting along a single axis, in particular, has generated considerable interest but has thus far been achieved only by the creation of structural anisotropy. In this paper, we report that such directional wetting can also be achieved by anisotropically coating nanostructure surfaces with materials that modify the nanostructure surface energy, a phenomenon that has not been observed in natural or artificial systems thus far. Moreover, by combining this newfound chemical influence on wetting with topographic features, we are able to restrict wetting in one, two and three directions. A model that explains these findings in terms of anisotropy of the pinning forces at the triple phase contact line is presented. Through the resulting insights, a flexible method for precise control of wetting is created.     

Temperature-dependent changes in erythrocytes' cytosol state during natural and artificial hypobiosis

At present, the question of how the structural state of the erythrocyte cytosol is arranged to maintain essential permeabilities successfully both at normal temperature and during periods with a significant body temperature reduction during hypobiosis remains unanswered. In the present work, we performed comparative investigations of temperature-dependent changes in the cytosol state of erythrocytes from animals subjected to natural (winter hibernating ground squirrels) or artificial hypobiosis. The cytosol state was evaluated by the ESR method of spin probes (TEMPON) within the temperature range of 0-50 degrees C. Erythrocyte resistance to acid hemolysis, which is limited by the permeability of membranes for protons and the state of the anion channel, were determined using the method described by Terskov and Getelson [Biofizika 2 (1957) 259]. A change in cytosol microviscosity of erythrocytes was found as well as a temperature-dependent increase in acid resistance of erythrocytes. Our investigations allow us to conclude that physiological changes occurring in a mammalian organism during natural and artificial hypobiosis are accompanied by structural modifications of the erythrocyte cytosol. The temperature range where these modifications are observed (8, 15, 40 degrees C) suggests that the most probable modifying link is spectrin and/or the sites of its interaction with membrane. The interaction of cytoskeletal components with the cell membrane plays a key role in regulation of membrane permeability, suggesting an important role of this interaction in the adaptive reactions of erythrocytes.