一种基于DNA G-四链体结构的汞离子快速检测方法

随着工业的发展汞污染日渐严重,建立一种快速、准确的Hg²⁺检测手段变得更加重要。某些富鸟嘌呤(G)的核酸序列能够通过氢键和自身链或者其他序列链上的鸟嘌呤(G)连接折叠成为四链结构,称为G-四链体。Hg²⁺可以和G-四链体中的胸腺嘧啶T相互作用形成T-Hg²⁺-T结构,G-四链体也会形成DNA双链结构,这种变化可以影响菁染料的聚集状态,进而引起溶液紫外-可见吸收光谱的变化。基于DNA G-四链体转化菁染料聚集状态开发了一种Hg²⁺检测手段。     

研究G-四链体与其配体相互作用的技术方法概述

近年来以G-四链体DNA为药物靶点的研究引起了人们的广泛关注,G-四链体与其配体相互作用的研究方法也多种多样.本文对研究G-四链体形成的结构,配体与G-四链体结合能力,配体与G-四链体结合模式等三个方面的技术方法进行了综述.     

钌(Ⅱ)多吡啶配合物与G-四链体DNA的相互作用研究

应用圆二色光谱、紫外-可见吸收光谱、荧光光谱等实验研究在H2O溶液中钌(II)多吡啶配合物[Ru(phen)2(Hecip)](ClO4)2(phen=1,10-邻菲啰啉,Hecip=2(9-乙基-9H-咔唑-3-基)-1H-咪唑并[4,5-f][1,10]菲啰啉)与G-四链体DNA(AG3(T2AG3)3)相互作用。圆二色光谱实验表明,配合物能够诱导无序的G-四链体DNA以平行构型和反平行构型的共存体存在;从紫外和荧光滴定实验表明配合物与G-四链体之间存在较强的亲和力,拟合得到的结合常数可达106。     

钌(Ⅱ)多吡啶配合物与G-四链体DNA的相互作用研究

应用圆二色光谱、紫外-可见吸收光谱、荧光光谱等实验研究在H2O溶液中钌(II)多吡啶配合物[Ru(phen)2(Hecip)](ClO4)2(phen=1,10-邻菲啰啉,Hecip=2(9-乙基-9H-咔唑-3-基)-1H-咪唑并[4,5-f][1,10]菲啰啉)与G-四链体DNA(AG3(T2AG3)3)相互作用。圆二色光谱实验表明,配合物能够诱导无序的G-四链体DNA以平行构型和反平行构型的共存体存在;从紫外和荧光滴定实验表明配合物与G-四链体之间存在较强的亲和力,拟合得到的结合常数可达106。     

异喹啉类生物碱和G-四链体结合的分子动力学研究

G-四链体是核酸的一种非经典二级结构,主要出现于富含鸟嘌呤（G）碱基的DNA或RNA序列。生物体内的G-四链体主要形成于端粒区域和某些原癌基因的启动子区域,是生物医学研究的重要对象。以G-四链体作为靶点的抗癌策略虽被多次提出,但目前还未有成功进入临床试验的案例。因此,有关原癌基因启动子区域的G-四链体与配体结合的研究,可以对靶向抗癌药物的设计提供指导性建议。使用分子动力学模拟的方法,研究了不同的异喹啉类生物碱与G-四链体的结合机理。通过考察四种异喹啉配体与G-四链体结合的过程,得到了异喹啉配体与G-四链体稳定结合的构象以及结合的主导因素。此工作从原子分子层面深化了对异喹啉类生物碱和G-四链体结合机理的微观认识,对抗癌药物设计具有指导意义。     

基于智能高分子材料的灵敏检测技术研究进展

近年来,将智能高分子材料识别响应的微小刺激信号转化并放大为方便人们读取的信号检测技术成为研究热点。本工作综述了近年来基于智能高分子材料的灵敏检测技术的研究进展,重点介绍了将智能高分子材料识别响应刺激信号转化为电信号、流量信号和光信号的检测技术。最后讨论了基于智能高分子材料的灵敏检测技术应用时需解决的关键问题,为基于智能高分子材料的灵敏检测技术的设计与应用提供了有价值的参考。     

A simple and sensitive method for lactose detection based on direct electron transfer between immobilised cellobiose dehydrogenase and screen-printed carbon electrodes

A rapid and simple approach of lactose analysis is proposed based on 3rd generation amperometric biosensors employing cellobiose dehydrogenase (CDH) from Trametes villosa or Phanerochaete sordida immobilised on screen-printed carbon electrodes (SPCEs). After optimisation of the working conditions of the biosensors - pH of the carrier buffer, flow rate and applied potential - the sensors were able to detect lactose in a concentration range between 0.5-200 μM and 0.5-100 μM employing T. villosa and P. sordida CDH, respectively. The limit of detection is 250 nM (90 μg/L) for both. Biosensors based on SPCEs modified with multiwalled carbon nanotubes showed a higher sensitivity than unmodified SPCEs. Cross-linking with glutaraldehyde or poly(ethyleneglycol)diglycidyl ether improved not only the stability but also the analytical response. The developed sensor has been successfully applied for the determination of lactose in dairy (milk with different percentages of fat, lactose-free milk and yogurt) with a good reproducibility (RSD = 1.5-2.2%). No sample preparation except a simple dilution process is needed. The biosensor is easy to make and operate, is inexpensive and reveals a high sensitivity and reliability.     

A facile method for the detection of DNA by using gold nanoparticle probes coupled with dynamic light scattering

In this paper, we present a simple and rapid method for deoxyribonucleic acid (DNA) detection using gold nanoparticle probes coupled with dynamic light scattering (DLS) analysis. The redox agent 1,4-dithio-dl-threitol cross-links the gold nanoparticles (AuNPs) to form clusters, while the monothiol DNA could terminate the formation and stabilize the assembled clusters by their negatively charge-based repulsions. By varying the concentration of DNA, the different sizes of DNA-AuNP clusters can be obtained. The sizes of the DNA-AuNP clusters were determined by DLS. A linear correlation was obtained between the sizes and the logarithm of DNA concentration from 2 nM to 5 μM with a detection limit of 1 nM (S/N = 3).     

A DNA electrochemical sensor with poly-l-lysine/single-walled carbon nanotubes films and its application for the highly sensitive EIS detection of PAT gene fragment and PCR amplification of NOS gene

A sensitive and novel DNA electrochemical biosensor for the detection of the transgenic plants gene fragment by electrochemical impedance spectroscopy (EIS) was presented. The well-dispersed carboxylic group-functionalized single-walled carbon nanotubes (SWNTs) were dripped onto the carbon paste electrode (CPE) surface firstly, and poly-l-lysine films (pLys) were subsequently electropolymerized by cyclic voltammetry (CV) to prepare pLys/SWNTs/CPE. The morphology of pLys/SWNTs films was examined using a field emission scanning electron microscope (SEM). The pLys/SWNTs films modified electrode exhibited very good conductivity. DNA probes were easily immobilized on the poly-l-lysine films via electrostatic adsorption. The hybridization events were monitored with electrochemical impedance spectroscopy using [Fe(CN)₆]^3−/4− as indicator. The PAT gene fragment from phosphinothricin acetyltransferase gene was detected by this DNA electrochemical sensor. The dynamic detection range of this sensor to the PAT gene fragment was from 1.0 × 10⁻¹² to 1.0 × 10⁻⁷ mol/L. A detection limit of 3.1 × 10⁻¹³ mol/L could be estimated. The PCR amplification of NOS gene from the sample of a kind of transgenic modified bean was also detected satisfactorily by EIS.