荧光纳米生物传感器研究进展

荧光纳米生物传感器检测物质具有灵敏度高、响应迅速、抗干扰性强、无需参比电极等特点而被广泛地运用于生物传感技术领域。本文综述了荧光纳米生物传感器种类和特点,介绍了国内外近期在荧光纳米生物传感器及在生物检测方面的一些研究成果及进展,并作了分析比较。着重讨论了纳米粒子荧光生物传感器和光纤纳米荧光生物传感器的特性及其在生物分析中的应用。     

基于纳米酶的比色生物传感器在生物医学检测中的应用

比色生物传感技术由于具有灵敏度高、方法简单并且容易操作等优点，已广泛应用于生物环境中污染物检测、生物体内重要标志物的检测以及癌症筛查等多个领域。基于纳米酶的比色生物传感器主要是借助纳米酶自身所具有的催化能力，模拟类过氧化物酶活性，将显色剂氧化生成有色溶液，从而实现可视化检测，并通过对有色溶液吸光度的检测得到相关物质的含量。与无纳米酶的比色生物传感器相比，基于纳米酶的比色生物传感器具有选择性更高、检测更快以及灵敏度更高等优点。纳米酶在具有天然酶活性的同时还具有成本低、稳定性好的、易于合成等优点，其相关研究越来越广泛。目前，基于纳米酶的比色生物传感器已成为辅助相关医学检测的重要方法，同时也广泛应用于便携和实时性相关检测当中，为医学检测提供了重要的支持和保障。为了提高比色生物传感器的灵敏度以及应用范围，研究人员也在致力于增加可检测物质的种类以及纳米酶种类的多样化等。本文主要介绍基于纳米酶的比色生物传感器的检测原理、几类典型的纳米酶，以及基于纳米酶的比色生物传感器在生物医学检测领域中的应用情况和研究进展。     

纳米粒子标记DNA探针在电化学DNA生物传感器中的应用

介绍了纳米电化学DNA生物传感器的基本概念和分类,并介绍了用于DNA标记的纳米粒子的六种类型及其三大检测方法,在此基础上对纳米电化学DNA生物传感器在基因检测、疾病诊断、DNA检测等方面的最新进展进行了综述与讨论.     

类过氧化物DNA酶在生物传感器领域的研究进展

随着对DNA酶研究的进展,DNA酶的很多优点已经超越了传统的蛋白质酶,具有过氧化物酶催化活性的DNA酶在电化学生物检测上拥有很大的潜力。我们简要阐述了DNA酶的特性和应用,描述了其基本性质,对DNA酶在生物分析领域的应用进行了展望。     

纳米粒子标记DNA 探针在电化学DNA 生物传感器中的应用

介绍了纳米电化学DNA生物传感器的基本概念和分类,并介绍了用于DNA标记的纳米粒子的六种类型及其三大检测方法,在此基础上对纳米电化学DNA生物传感器在基因检测、疾病诊断、DNA检测等方面的最新进展进行了综述与讨论。     

荧光铜纳米簇介导的生物传感器的研究进展

荧光铜纳米簇(Fluorescent copper nanoclusters,CuNCs)是以脱氧核糖核酸链(Deoxyribonucleic acid,DNA)为模板,以二价铜离子(Cu2+)、抗坏血酸等为反应物生成的铜晶体,纳米级大小,其具有荧光性,可以作为生物传感器输出信号的一种方式。荧光铜纳米簇的生成快速、简便、安全,因此近年来涌现出很多关于荧光铜纳米簇原理和应用方面的研究。从支持传感器工作的介导物质以及信号输出方式两方面对荧光铜纳米簇进行分类,详细阐述了每一类别传感器工作的原理,并对比同类型传感器的优缺点,最后对荧光铜纳米簇介导的生物传感器目前存在的不足及今后的发展趋势进行了展望。以便读者对荧光铜纳米簇生物传感器发展历程和方向,对荧光铜纳米簇生物传感器的实用性和多形性有所了解,在未来的研究发展中得到启示,使荧光铜纳米簇成为一种更加实用和便捷的生物传感工具。     

纳米级金微粒在DNA生物传感器研究中的应用

纳米金颗粒具有独特的物理、化学性质和良好的生物兼容性,已广泛应用于生命科学研究中的示踪技术.将该技术与DNA传感器相结合,可显著提高生物传感器的灵敏度,缩短检测时间和提高检测通量,已成为近年来的研究重点.     

FEN1酶介导的功能核酸生物传感器的研究进展

瓣状核酸内切酶-1(Flap endonuclease 1,FEN1)是一种可以识别三碱基重叠结构(三核酸)并对其进行切割,释放出5’-flap片段的结构特异性酶,并且有着高效稳定的切割效率。基于此种特性,通过不同的信号输出方式,FEN1酶现被用于DNA、RNA、病毒等放大检测中。首先对FEN1酶的发现、性质以及作用方面做了相应介绍,然后根据所检测的靶物质不同,对FEN1酶所介导的生物传感器进行分类,主要包括对单核苷酸多态性的检测、甲基化检测、基因型检测、RNA检测、病毒检测、肿瘤检测和微生物检测等。此外,对FEN1酶与纳米材料的结合以及体内表征及治疗也进行了较为详细的介绍。同时,还对传感器之间的原理、灵敏度、特异性及适用领域等方面进行比较和优缺点的简单评价。最后,对FEN1酶所介导的生物传感器的中存在的不足,以及未来的发展方向进行了展望,旨在为今后研发更便携、更灵敏、更准确的FEN1功能核酸生物传感器提供理论参考。     

DNA生物传感器研究进展

本根据作用机理不同将ＤＮＡ生物传感器分为ＤＮＡ光化学传感器,ＤＮＡ电化学传感器和压电晶体传感器,并就几种方面的研究进展进行了综述。     

肌苷酶电极生物传感器

为了构建肌苷酶电极生物传感器,以固定化核苷磷酸化酶(EC 2.4.2.1)、黄嘌呤氧化酶(EC 1.2.3.2)与过氧化氢电极组成电流型酶电极生物传感器,用于检测肌苷片中的肌苷,其输出电流可达500nA.结果发现,肌苷测定的线性范围为1-268 mg/L,精度:RSD小于0.14%,响应时间:60 s,使用寿命大于25 d,实际测定肌苷片中肌苷含量回收率:100.8%.由此表明:采用双酶电极法测定肌苷片中的肌苷含量,由于酶促反应专一性高、样品不需分离直接进样分析、处理条件温和、反应时间短暂因而结果较为可靠.     

胆碱氧化酶电极生物传感器研究

以固定化胆碱氧化酶(EC 1.1.3.17)与H₂O₂电极构成电流型酶电极生物传感器．其输出电流可达500nA。用于胆碱测定的线性范围：0～200mg／L,精度：RSD小于1．5％．响应时间：40s,使用寿命大于60d,实际测定氯化琥珀胆碱注射液中胆碱含量,回收率：1OO．3％～102．3％。     

生物标志物在前列腺炎中的研究进展

前列腺炎是男性泌尿系统的常见疾病,由于前列腺炎存在病因和发病机制复杂,导致临床症状表现多种、药物治疗缺乏特异性和复发率较高等问题,因此前列腺炎的诊断、治疗和预后判断标准一直是临床关注的焦点。目前还没有诊断前列腺炎的"金标准",而生物标志物的检测有助于临床诊断、治疗和预后诊断,本文检索近年相关,对敏感性较高和特异性较好的一些前列腺炎生物标志物(细胞因子和趋化因子等)及今后研究的侧重点进行综述,从而为前列腺炎的诊断、分型治疗和预后观察提供依据。     

酶电极法快速测定甘油含量的研究

利用酶固定化技术,以甘油激酶（GK）、甘油-3-磷酸氧化酶（GPO）为反应酶,研究GK、GPO的固定化方法及固定化模式,制备甘油酶膜、甘油酶电极,并利用其测定甘油含量。结果表明,GK、GPO按1：1比例固定化时,酶电极电流信号最高;最高效固定模式为：GK固定于核微孔膜,共价偶联GPO固定于Biodyne膜,形成共价双酶膜,进而组装为甘油酶电极。性能研究表明,甘油酶电极最适pH值为7.0,最佳温度为28~32℃;最佳实验条件下,线性范围为0.05~9.00 g/L;回收率为98.4%~102.4%,稳定性高,相对标准偏差（RSD）<5%;测定结果与高效液相色谱法、高碘酸氧化法比较,无明显差异（P>0.05）,且该方法操作简单,专一性强,检测快速,适于实际生产中甘油的实时定量及监控。     

酶分子体外定向进化的研究进展

分子体外定向进化是改造酶分子的新策略,它主要通过体外模拟自然进化机制,利用基因随机突变、重组和定向筛选技术,使进化过程朝着人们需要的方向发展。简要介绍了酶分子体外定向进化的发展历史,详细介绍了突变文库构建和筛选方法的最新研究进展及应用情况。     

酶催化反应驰豫时间的布尔函数图解法

证明可使用布尔函数图论方法＾「１」来研究酶反应驰豫时间问题,所用方法与解决酶催化反应驰豫时间的Ｋｉｎｇ－Ａｌｔｍａｎ法＾「２」相比,具有图形鲜明、绘法简易、使用方便（不需画出支撑入树之类的图形,不需代数运算）、结果可靠（不易发生遗漏或错算）等优点。列举一类酶反应体系（Ｅ等价于ＥＳ等价于ＥＳ＾＊）作为此图形方法求解的实例。     

Progress Curves Analysis as an Alternative for Exploration of Activation-inhibition Phenomena in Cholinesterases

The kinetic behaviour of insect acetylcholinesterases deviates from the Michaelis-Menten pattern. These deviations are known as activation or inhibition at various substrate concentrations and can be more or less observable depending on mutations around the active site of the enzyme. Most kinetic studies on these enzymes still rely on initial rate measurements. It is demonstrated here that according to this method one of the deviations can be overlooked. We attempt to point out that in such cases a detailed step-by-step progress curves analysis is successful. The study is focused on two different methods of analysing progress curves: (i) the first one is based on an integrated initial rate equation which can sufficiently fit truncated progress curves under corresponding conditions; and (ii) the other one precludes the algebraic formulae, but uses numerical integration for searching a non analytical solution of ordinary differential equations describing a kinetic model. All methods are tested on three different acetylcholinesterase mutants from Drosophila melanogaster. The results indicate that kinetic parameters for the E107K mutant with highly expressive activation and inhibition can be well evaluated applying any analysis method. It is quite different for E107W and E107Y mutants where latent activation is present, but discovered only using one or the other progress curves analysis methods.     

Introduction to the Thematic Minireview Series on Enzyme Evolution

In this thematic minireview series, the JBC presents five provocative articles on Enzyme Evolution. The reviews discuss stimulating concepts that include the emergence of primordial catalysts at temperatures that were considerably warmer than present day ones and the impact of the cooling environment on the evolution of catalytic fitness and the preservation of catalysis-promoting conformational dynamics. They also discuss the use of Urzymes or invariant modules in enzyme superfamilies as paradigms for understanding the evolution of catalytic efficiency and specificity, the use of bioinformatics approaches to understand the roles of substrate ambiguity and catalytic promiscuity as drivers of evolution, and the challenges associated with assigning catalytic function as the number of superfamily members grows rapidly.     

Mechanistic Study of Uba5 Enzyme and the Ufm1 Conjugation Pathway

E1 enzymes activate ubiquitin or ubiquitin-like proteins (Ubl) via an adenylate intermediate and initiate the enzymatic cascade of Ubl conjugation to target proteins or lipids. Ubiquitin-fold modifier 1 (Ufm1) is activated by the E1 enzyme Uba5, and this pathway is proposed to play an important role in the endoplasmic reticulum (ER) stress response. However, the mechanisms of Ufm1 activation by Uba5 and subsequent transfer to the conjugating enzyme (E2), Ufc1, have not been studied in detail. In this work, we found that Uba5 activated Ufm1 via a two-step mechanism and formed a binary covalent complex of Uba5∼Ufm1 thioester. This feature contrasts with the three-step mechanism and ternary complex formation in ubiquitin-activating enzyme Uba1. Uba5 displayed random ordered binding with Ufm1 and ATP, and its ATP-pyrophosphate (PP_i) exchange activity was inhibited by both AMP and PP_i. Ufm1 activation and Uba5∼Ufm1 thioester formation were stimulated in the presence of Ufc1. Furthermore, binding of ATP to Uba5∼Ufm1 thioester was required for efficient transfer of Ufm1 from Uba5 to Ufc1 via transthiolation. Consistent with the two-step activation mechanism, the mechanism-based pan-E1 inhibitor, adenosine 5′-sulfamate (ADS), reacted with the Uba5∼Ufm1 thioester and formed a covalent, tight-binding Ufm1-ADS adduct in the active site of Uba5, which prevented further substrate binding or catalysis. ADS was also shown to inhibit the Uba5 conjugation pathway in the HCT116 cells through formation of the Ufm1-ADS adduct. This suggests that further development of more selective Uba5 inhibitors could be useful in interrogating the roles of the Uba5 pathway in cells.     

Impact of the Enzyme Flexibility on the Enzyme Enantio-selectivity in Organic Media Towards Specific and Non-specific Substrates

A rationale is presented as to why the enantioselectivity of enzymes in dry organic media towards specific substrates is increased when the enzyme flexibility is increased. This is outlined for serine proteases towards N -acetyl-amino acid esters. The reasons why this relationship does not hold in the case of non-specific substrates are discussed.     

Impact of the Enzyme Flexibility on the Enzyme Enantio-selectivity in Organic Media Towards Specific and Non-specific Substrates

A rationale is presented as to why the enantioselectivity of enzymes in dry organic media towards specific substrates is increased when the enzyme flexibility is increased. This is outlined for serine proteases towards N -acetyl-amino acid esters. The reasons why this relationship does not hold in the case of non-specific substrates are discussed.