DNA生物传感器:缓慢的传感器?

近几年来,酶传感器、免疫传感器及微生物传感器等发展较为成熟,而DNA生物传感器的研究相对较少。文章从核酸杂交的原理出发介绍了DNA生物传感器的工作原理,举例说明了电化学、光学和声学等几种典型的DNA生物传感器,指出了其固有的优缺点,肯定了DNA传感器发展前景。     

分子信标在DNA生物传感器中的应用

DNA传感器是基于DNA分子相互作用原理设计而成的一种新型的检测技术,具有快速,简单等优点,在基因分析及其他应用领域已显示出越来越重要的价值.分子信标是一种具有发卡式结构的寡核苷酸,由于其能够很好地识别单碱基错配序列,基于发卡式DNA的传感器较传统的单链DNA传感器有更好的检测特异性,目前得到广泛的研究.本文介绍了DNA生物传感器及分子信标的有关原理,并着重介绍了发卡式DNA的结构及其在DNA生物传感器中的应用.     

基于DNA分子导线的纳米生物传感器

DNA分子导线具有独特的导电性能和塞贝克(Seebeck)效应,它是构筑电化学纳米生物传感器和热电偶生物传感器的理想材料。文章简要介绍了DNA分子导线的制备方法及导电机理,以及基于DNA分子导线的纳米生物传感器的分子识别机制,着重分析了基于DNA分子导线的纳米生物传感器的传感原理。文章还介绍了基于DNA分子导线的纳米生物传感器在基因分析、单碱基突变检测等方面的应用。     

DNA生物传感器在环境污染监测中的应用

基于生物催化和免疫原理的生物传感器在环境领域中获得了广泛应用.近年来,随着分子生物学和生物技术的发展,人们开发了以核酸探针为识别元件,基于核酸相互作用原理的DNA生物传感器.该传感器可用于受感染微生物的核酸序列分析、优先控制污染物的检测以及污染物与DNA之间相互作用的研究,在环境污染监测中具有潜在的巨大应用前景.简要介绍了核酸杂交生物传感器的基本原理及其在环境微生物和优先控制污染物（priority pollutant）检测中的应用研究进展.     

生物传感器应用于食源性致病菌检测研究进展

生物传感器技术是一种由生物、化学、物理、医学、电子技术等多种学科互相渗透形成起来的高新微量分析技术,具有选择性好、灵敏度高、分析速度快、成本低、能在复杂的体系中进行在线连续监测的特点.本文根据生物传感器的分子识别元件将生物传感器分为DNA传感器、免疫传感器、细胞传感器三大类,简要介绍各种生物传感器的原理及其在检测食源性致病菌方面的应用情况,并对未来生物传感器应用于实际检测进行了展望.     

阵列电化学生物传感器研究进展

阵列生物传感器技术作为一种高通量、快速、选择性高和集成化的分析技术,已在基因组学和蛋白质组学的研究和药物筛选、环境分析,食品分析,临床诊断等领域中得到广泛的应用.阵列生物传感器主要有阵列光学生物传感器和阵列电化学生物传感器.阵列电化学生物传感器是将生物分子识别物质如酶、抗原/抗体、DNA等固定在阵列电极上,以阵列中每根电极产生的电化学信号作为检测信号的电化学分析器件.阵列电化学生物传感器以灵敏度高、分析速度快、选择性好、易于微型化和集成化以及仪器价格低廉等特点受到了研究工作者的极大关注.本文简单介绍了阵列电化学生物传感器的原理和特点,重点评述了2005年以来阵列电化学生物传感器在单组份检测和多组份同时检测两方面的研究进展,简单讨论了阵列电化学生物传感器研究中存在的问题.     

末端脱氧核酸转移酶介导的功能核酸生物传感器研究进展

末端脱氧核酸转移酶(TdT酶)是一种DNA聚合酶,可以催化脱氧核苷酸结合到DNA分子的3'羟基端,并且该反应无需特定的模板。目前,基于末端脱氧核酸转移酶可对模板核酸链的末端进行延伸这一特性,搭载不同的信号输出及扩增方式,构建了一系列的生物传感技术,如电化学生物传感器、荧光生物传感器、表面离子共振生物传感器等。对各类传感器的基本设计原理和应用进行了阐述。根据TdT酶的性质设计的一系列生物传感器具有简单、快速、廉价、灵敏度高、特异性好等优点,实现了对金属离子、病原体、蛋白质等的检测。最后对TdT酶介导的生物传感器目前的研究现状进行了总结并且对TdT酶未来的发展方向进行了展望。     

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.     

电场驱动微悬臂生物传感器及对DNA 的快速、高灵敏度检测

微悬臂列阵传感器在生物检测方面具有快速、痕量和非标记的特性. 我们以镀金并在其上固定了 DNA 探针的微悬臂为正极,在靶杂交液槽内引入另一电极作为负极,构成电场驱动微悬臂 DNA 生物传感器. 对该传感器系统施加静电场,驱动 DNA 分子朝正极迁移,使溶液中的 DNA 分子富集在微悬臂上,促进 DNA 分子的杂交. 结果表明： a. DNA 在微悬臂上的杂交时间仅需 3 min,加快了微悬臂生物传感器对 DNA 分子的检测速度; b. 提高了微悬臂生物传感器的灵敏度,可以检测到皮克级的 DNA 分子.     

场效应晶体管生物传感器在生物医学检测中的应用研究进展*

场效应晶体管生物传感器因其灵敏度高、分析速度快、无标记、体积小、操作简单等特点而受到了很多关注,广泛应用于DNA、蛋白质、细胞、离子等生物识别物的检测。近年来,更有纳米材料和微电子技术在传感器设计中提高传感器的传感性能,场效应晶体管生物传感器朝着高灵敏、微型化、快速化以及多功能化的方向以令人惊叹的速度发展。研究场效应晶体管生物传感器工作原理,阐述近年来场效应晶体管生物传感器在生物医学检测领域中最新的研究进展与应用,探讨场效应晶体管生物传感器克服各种缺陷的应对策略,为该传感器在未来生物医学检测中的开发提供参考。     

DNA生物传感器及其研究进展

就ＤＮＡ生物传感器的工作原理,分类、ＤＮＡ探针的固化方法,以及电化学ＤＮＡ生物传感器、光学ＤＮＡ生物传感器及压电ＤＮＡ生物传感器的研究进展、优缺点和发展趋势加以介绍。     

Rapid on-site detection of Acidovorax avenae subsp. citrulli by gold-labeled DNA strip sensor

Acidovorax avenae subsp. citrulli (AAC) is one of the most harmful diseases in cucurbit production. A rapid and sensitive DNA strip sensor was constructed based on gold nanoparticle-labeled oligonucleotide probes for the detection of AAC. Both the qualitative and semi-quantitative detections of target DNA were successfully achieved using the developed DNA strip sensor. The qualitative limit of detection (LOD) of the strip sensor was determined as 4 nM. The LOD for the semi-quantitative detection was calculated to be 0.48 nM in the range of 0-10 nM. The genomic DNA was detected directly using the DNA strip sensor without any further treatment. This DNA strip sensor is a potentially useful tool for rapid on-site DNA screening.     

Development of an electrochemical polypyrrole-based DNA sensor and subsequent studies on the effects of probe and target length on performance

DNA sensors have a wide scope of applications in the present and emerging medical and scientific fields, such as medical diagnostics and forensic investigations. However, much research-to-date on DNA sensor development has focused on short target DNA strands as model genes. In this communication we study the effect of the length of oligonucleotide probe and target strands as a significant step towards real world applications for DNA detection. The sensor technology described uses the conducting polymer polypyrrole as both a sensing element and transducer of sensing events - namely the hybridization of complementary target oligonucleotide to probe oligonucleotide. Detection is performed using electrical impedance spectroscopy. Initially sensor development is performed, wherein we demonstrate an improvement in stability and sensitivity as well as show a reduction in non-specific DNA binding for fabricated sensors, through use of a specific dopant and post-growth treatment. Subsequently, we show that longer target DNA strands display increased response, as do sensors containing longer probe DNA strands. It is suggested that these results are a feature of the increase in negative charges associated with the longer DNA strands. The results of this comparative study are aimed to guide future design of analogous sensors.     

A DNA sensor based on surface plasmon resonance for apoptosis-associated genes detection

A practical and simple DNA sensor based on surface plasmon resonance (SPR) had been developed to determine apoptosis-associated genes, bcl-2 and bax. This SPR sensor was designed on the basis of simultaneous multi-wavelength detection. The complementary sequences of bcl-2 or bax oligonucleotide labeled with biotin were used as the probes. Biotin-avidin system was used to immobilize the bio-DNA on the sensor surface. The assembling processes and conditions for the DNA sensor were examined. The SPR sensor could be used to monitor the process of the immobility of the bio-DNA and DNA hybridization in real-time. The determination range of bcl-2 and bax oligonucleotide (20 bases) were 50-400 ng/mL. The determination range of polymerase chain reaction (PCR) product of bcl-2 (405 bases) was 5-60 ng/mL and PCR product of bax (538 bases) was 5-40 ng/mL. The stability, reversibility and specificity of the DNA sensor were also investigated. It was found from the experiment that the sensor could be applied for a quite long time (about 90 times). The relative standard deviation (R.S.D.) for determination oligonucleotides and PCR products of bcl-2 were 1.2 and 1.3%, respectively. The interference of noncomplementary DNA sequence with the determination of DNA was examined and it was found that noncomplementary 20-mer and 21-mer DNA (p53 and p21) do not affect the determination of bcl-2 or bax. This device could be used to study apoptosis and signal transduction routine genes. The sensor was shown to be of simplicity, sensitivity, selectivity, rapid response and cost effectiveness.     

A sensitive signal-on assay for MTase activity based on methylation-responsive hairpin-capture DNA probe

This work develops a simple, sensitive and signal-on electrochemical sensor for methyltransferase (MTase) activity analysis. The sensor is composed of a methylene blue-modi?ed "signaling DNA probe" and a "capture DNA probe" tethered methylation-responsive hairpin DNA (hairpin-capture DNA probe). The thiol- modified hairpin-capture DNA probe at 5' end was firstly self-assembled on gold electrode via Au-S bonding. Methylation-induced scission of hairpin-capture DNA probe would displace the hairpin section and remain the "capture DNA probe" section on the gold electrode. Subsequently, the remained "capture DNA probe" on the gold electrode can hybridize with the methylene blue-modi?ed "signaling DNA probe", mediating methylene blue onto the gold electrode surface to generate redox current. It was eT on state. The developed facile signal-on electrochemical sensing system showed a linear response to concentration of Dam MTase range from 0.1 to 1.0 U/mL. The detection limit of Dam MTase activity was determined to be 0.07 U/mL and the total detection time is 7h. The sensor also has the ability to provide information about the dynamics of methylation process. Furthermore, we demonstrated that this sensor could be utilized to screen inhibitors or drugs for Dam MTase.     

Nano-moles detection of tumor specific biomarker DNA for colorectal cancer detection using vertically aligned multi-wall carbon nanotubes based flexible electrodes

A genosensor, flexible and low cost as well, has been fabricated to efficiently detect colorectal cancer cell by targeting CEACAM5, a tumor biomarker. Sensing electrode was fabricated with efficient transfer of a pattern of vertically aligned multi-wall carbon nanotubes on flexible polyethylene terephthalate (PET) substrate by hot press technique, a technologically advanced one. The purpose was to make the sensor device stretchable, bendable, transparent, disposable and heat resistant; without losing the pristine character of the electrode material before and after transfer process. Fabricated sensor was characterized by cyclic voltammetry (CV) and electrochemical impedance spectra (EIS). The sensor response was checked by adding target DNA within a range of 50–250 μM and sensor showed a detection limit of 0.92μM; exhibited good linearity with a regression coefficient of 0.96 obtained through calibration plot. The sensor was found to be highly sensitive, stable and good specificity as binding occurs only with the complementary DNA. Besides, the genosensor showed relative standard deviation of 6.5 % and 6.7 % at respective 100 μM and 150 μM complementary DNA concentrations. Reproducibility and stability are two crucial parameters where the developed sensor have scored extremely well.     

A T7exonuclease‐assisted target recycling amplification with graphene oxide acting as the signal amplifier for fluorescence polarization detection of human immunodeficiency virus (HIV) DNA

We report a fluorescence polarization (FP) platform for human immunodeficiency virus (HIV) DNA detection based on T7exonuclease‐assisted target recycling amplification with graphene oxide (GO) acting as a FP signal amplifier. In the sensing method, the presence of the target DNA leads to target recycling with the assistance of T7exonuclease, furthermore, the amplification products are absorbed onto the surface of GO, so the all FP values are enhanced by GO. More importantly, this FP sensor exhibits high detection sensitivity; under optimal conditions, the change in FP is linear with the concentration of the target DNA within a concentration range of 50–2000 pmol/L, and the detection limit of this method is as low as 38.6 pmol/L. This FP sensor also exhibits high selectivity, even single‐base mismatched DNA can be effectively discriminated from complementary target DNA. Above all, the proposed FP sensor may serve as a general platform for the sensitive assay of disease‐related genes. Copyright © 2015 John Wiley & Sons, Ltd.     

An FET-type charge sensor for highly sensitive detection of DNA sequence

We have fabricated an field effect transistor (FET)-type DNA charge sensor based on 0.5 microm standard complementary metal oxide semiconductor (CMOS) technology which can detect the deoxyribonucleic acid (DNA) probe's immobilization and information on hybridization by sensing the variation of drain current due to DNA charge and investigated its electrical characteristics. FET-type charge sensor for detecting DNA sequence is a semiconductor sensor measuring the change of electric charge caused by DNA probe's immobilization on the gate metal, based on the field effect mechanism of MOSFET. It was fabricated in p-channel (P) MOSFET-type because the phosphate groups present in DNA have a negative charge and this charge determines the effective gate potential of PMOSFET. Gold (Au) which has a chemical affinity with thiol was used as the gate metal in order to immobilize DNA. The gate potential is determined by the electric charge which DNA possesses. Variation of the drain current versus time was measured. The drain current increased when thiol DNA and target DNA were injected into the solution, because of the field effect due to the electrical charge of DNA molecules. The experimental validity was verified by the results of mass changes detected using quartz crystal microbalance (QCM) under the same measurement condition. Therefore it is confirmed that DNA sequence can be detected by measuring the variation of the drain current due to the variation of DNA charge and the proposed FET-type DNA charge sensor might be useful in the development for DNA chips.     

DNA hybridization assay at individual,biofunctionalized zinc oxide nanowires

Reliable and efficient identification of DNA is a major goal in on‐site diagnostics. One dimensional nanostructures like nanowires (NW) represent potential sensor structures due to their extreme surface‐to‐bulk ratio, enabling enhanced biomolecule binding which results in optimal signals. While silicon NW are already well studied, NW made from other materials with promising properties like ZnO are not yet established as NW sensor material for bioanalytics. Here we demonstrate the DNA functionalization of ZnO NW even at the single NW level and their successful application in a DNA hybridization assay. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)