光学适配体传感器检测赭曲霉毒素A的研究进展

赭曲霉毒素A(Ochratoxin A,OTA)是真菌产生的次级代谢产物,性质稳定,不易去除,人体摄入后将产生严重的健康危害。数十年来,核酸适配体不断发展,成为生物传感器的重要识别元件之一,适体传感器被广泛用于生物、医药、疾病等分析检测。本文总结了用于检测OTA的经典方法和基于核酸适配体的生物传感器方法,并主要从光学适配体传感器方面阐述了近年用于检测赭曲霉毒素A的适配体传感器,并对其进行了总结和展望。     

赭曲霉毒素A的电化学适体传感检测

赭曲霉毒素A （OTA）是一类主要由曲霉属和青霉属等真菌产生的小分子有毒次级代谢产物,广泛存在于食品、农产品和动物饲料中,具有强烈肝毒性、肾毒性、致畸和致突变等作用,亦是ⅡB类致癌物。鉴于OTA污染的普遍性和危害性,本文就目前OTA的常用检测方法进行概述和比较,重点阐述新型电化学适体传感技术在OTA检测方面的相关应用。全面综述了构型变换型、亲合型以及混合型OTA电化学适体传感器的原理、优缺点及最新研究进展,并对OTA电化学适体传感器的未来发展方向提出展望,为电化学适体传感器的深入研究与应用提供参考。     

基于电化学传感器检测赭曲霉毒素A的研究进展

赭曲霉毒素A(Ochratoxin A,OTA)是一种由赭曲霉、青霉菌等真菌产生的次级代谢产物,在自然界分布广泛,具有肝毒性、肾毒性、致癌、致突变作用。鉴于其危害的严重性和污染的广泛性,发展高灵敏度的OTA检测技术引起了研究者的广泛关注。该文阐述了近年来新型电化学传感技术在OTA 检测方面的发展及应用,全面综述了目前OTA电化学传感器的主要类型及其优缺点,并对其发展方向提出了展望,从而为基于OTA的电化学传感器的深入研究与应用提供了参考。     

构建电化学适配体传感器快速检测中药材中的赭曲霉毒素A

利用壳聚糖（CS）、还原氧化石墨烯（rGO）与氮掺杂多壁碳纳米管（N-MWCNTs）合成N-MWCNTs-rGO-CS复合材料,制备修饰电极,结合赭曲霉毒素A(OTA)的特异性适配体,构建高灵敏度电化学生物传感器,并用于中药中OTA的含量测定。在最优条件下,峰电流变化值与OTA浓度对数值的线性响应范围为2.3 pmol/L～2.3 nmol/L,检测限为0.53 pmol/L。应用该方法对中药饮片中OTA的含量进行加标回收实验,回收率在97.6%～103.2%之间。该方法有望用于中药材中OTA污染的快速检测。     

光学适配体传感器检测赭曲霉毒素A的应用进展

赭曲霉毒素A(OTA)是由曲霉和青霉产生的一种真菌毒素,具有强烈的肝肾毒性,并有致畸、致癌的危害。OTA广泛存在于如小麦、玉米、咖啡、葡萄等谷物及食品中,严重危害人类健康。鉴于其危害的严重性和分布的广泛性,发展方便快捷、高灵敏度的OTA检测技术具有重要意义。目前检测OTA的方法有薄层色谱法、高效液相色谱法、荧光分析法及酶联免疫吸附测定法等,这些方法通常成本高、操作复杂且费时。光学适配体传感器发展迅速,在OTA检测领域表现出巨大优势,因此综述了荧光型（包括标记型和免标记型）、比色型、化学发光型以及其他类型（表面等离子体共振、侧向层析、表面增强拉曼散射型）光学适配体传感器检测OTA的原理、性能及在2011-2023年间的相关应用,并对方法面临的问题进行了总结以及未来的的发展趋势进行了展望（引用文献81篇）。     

金属有机框架用于电化学检测赭曲霉毒素A

以纳米金修饰电极为固定基质,建立一种基于金属有机框架的电化学生物传感器检测赭曲霉毒素A的方法。将核酸修饰的金属有机框架为信号探针,通过碱基互补识别作用将其捕获到适配体修饰的电极表面,此时可获得明显的电信号。当赭曲霉毒素A与适配体特异性结合后无法成功捕获金属有机框架,从而导致电信号降低。在0.1~5.0 nmol/L范围内,赭曲霉毒素A浓度与电信号呈良好的线性关系,检测限为0.03 nmol/L。该方法可成功用于红酒中赭曲霉毒素A的测定并有望用于食品中多种有害物质的实时检测。     

量子点荧光共振能量转移检测赭曲霉毒素A

基于量子点与荧光猝灭基团之间构成的荧光共振能量转移体系,以量子点标记赭曲霉毒素A适配体与荧光猝灭基团标记的补体杂交构成荧光传感探针,当有赭曲霉毒素A存在时,由于其适配体与赭曲霉毒素A的高度亲和作用,使传感探针上结合的荧光猝灭剂减少,荧光增强,从而建立了一种检测赭曲霉毒素A的荧光分析方法.该方法简单、快速、特异性强,在适...     

高灵敏赭曲霉毒素A电化学适配体传感器的构建

利用CdS QDs/SiO_2纳米粒子作为电子媒介体制备了一种高灵敏度的赭曲霉毒素A(OTA)电化学适配体传感器.实验过程中,首先合成了CdS QDs/SiO_2纳米粒子,之后采用透射电子显微镜、紫外吸收光谱方法等对制备的纳米材料进行了表征.该复合材料在保持了SiO_2纳米粒子良好的生物相容性和均一性的同时增加了CdS QDs的负载量,从而有利于传感器的信号放大.在组装过程中,先将捕获探针(cDNA)固定在金电极表面,适配体与捕获探针杂交形成双链,此时没有电化学信号;当OTA存在时,适配体会与OTA结合而从电极表面脱离,再将标记有CdS QDs/SiO_2纳米复合材料的信号探针(sDNA)与电极上自由的cDNA杂交,产生电化学信号.最优条件下,传感器电化学信号强度增加值与OTA浓度在0.5 pg/m L~10.0 ng/m L范围内呈现良好的线性关系,检测限低至0.091 pg/m L.     

基于上转换荧光纳米粒子和金纳米粒子间荧光共振能量转移的高灵敏赭曲霉毒素A检测方法研究

制备了水溶性的上转换荧光纳米材料,在其表面修饰赭曲霉毒素A(OTA)适配体作为能量供体探针;在金纳米粒子表面修饰OTA适配体互补链作为能量受体探针,构建了OTA适配体传感器。在最优条件下,OTA的检测范围为0.001~10 ng/mL,检出限可达0.001 ng/mL。将其应用于啤酒样品中OTA的检测,当加标水平为0.01、0.1、1.0 ng/mL时,回收率为100%~119%,相对标准偏差为4.3%~4.9%,表明该方法可用于实际样品检测。该方法具有灵敏度高、特异性好、操作简单、成本较低等优点。     

适配体生物传感器在黄曲霉毒素B1检测中的应用

该文首先对黄曲霉毒素B1（AFB1）的相关性质及其传统检测方法进行了介绍,随后概述了近年来基于光学、电化学以及微流控芯片的适配体生物传感器的构建及其在AFB1检测领域中的应用,旨为适配体生物传感器的实际应用提供参考;并通过探讨目前开发的检测方法存在的问题,对适配体生物传感器前景和未来趋势进行了展望。     

Electrochemical Aptasensor for the Determination of Ochratoxin A at the Au Electrode Modified with Ag Nanoparticles Decorated with Macrocyclic Ligand

An electrochemical aptasensor for ochratoxin A (OTA) detection has been developed on the base of a gold electrode covered with electropolymerized neutral red and silver nanoparticles obtained by chemical reduction with macrocyclic ligands bearing catechol fragments. Thiolated aptamers against OTA were covalently attached to silver nanoparticles via Ag? S bonding. The interaction with OTA induced the conformational switch of the aptamer, which caused increase of the charge transfer resistance measured by EIS in the presence of ferricyanide ions. The LOD achieved (0.05 nM) was comparable to other electrochemical aptasensors employing sophisticated assembling technique and enzyme amplification of the signal. The aptasensor was validated in spiked beer samples. The recovery of the OTA determination was found to be 66.3±14.1 % for light beer and 64.3±1.8 % for dark beer.     

核酸适配体识别-荧光法检测赭曲霉素A

建立了核酸适配体识别-荧光探针技术检测赭曲霉素A(OTA)的新方法.基于微孔板上固定的核酸适配子与目标物质OTA结合时构象发生变化,导致预先与其互补杂交的FAM标记短链DNA解离,引起荧光信号发生变化,据此可实现对OTA的定量检测.当微孔板包被亲和素浓度为25 mg/L、适配子浓度为50 nmol/L,FAM标记互补短...     

Direct detection of OTA by impedimetric aptasensor based on modified polypyrrole-dendrimers

Ochratoxin A (OTA) is a carcinogenic mycotoxin that contaminates food such as cereals, wine and beer; therefore it represents a risk for human health. Consequently, the allowed concentration of OTA in food is regulated by governmental organizations and its detection is of major agronomical interest. In the current study we report the development of an electrochemical aptasensor able to directly detect trace OTA without any amplification procedure. This aptasensor was constructed by coating the surface of a gold electrode with a film layer of modified polypyrrole (PPy), which was thereafter covalently bound to polyamidoamine dendrimers of the fourth generation (PAMAM G4). Finally, DNA aptamers that specifically binds OTA were covalently bound to the PAMAM G4 providing the aptasensor, which was characterized by using both Atomic Force Microscopy (AFM) and Surface Plasmon Resonance (SPR) techniques. The study of OTA detection by the constructed electrochemical aptasensor was performed using Electrochemical Impedance Spectroscopy (EIS) and revealed that the presence of OTA led to the modification of the electrical properties of the PPy layer. These modifications could be assigned to conformational changes in the folding of the aptamers upon specific binding of OTA. The aptasensor had a dynamic range of up to 5 μg L⁻¹ of OTA and a detection limit of 2 ng L⁻¹ of OTA, which is below the OTA concentration allowed in food by the European regulations. The efficient detection of OTA by this electrochemical aptasensor provides an unforeseen platform that could be used for the detection of various small molecules through specific aptamer association.     

Ultrasensitive one-step rapid detection of ochratoxin A by the folding-based electrochemical aptasensor

A one-step electrochemical aptasensor using the thiol- and methylene blue- (MB-) dual-labeled aptamer modified gold electrode for determination of ochratoxin A (OTA) was presented in this research. The aptamer against OTA was covalently immobilized on the surface of the electrode by the self-assembly effect and used as recognition probes for OTA detection by the binding induced folding of the aptamer. Under the optimal conditions, the developed electrochemical aptasensor demonstrated a wide linear range from 0.1 pg mL⁻¹ to 1000 pg mL⁻¹ with the limit of detection (LOD) of 0.095 pg mL⁻¹, which was an extraordinary sensitivity compared with other common methods for OTA detection. Moreover, as a practical application, this proposed electrochemical aptasensor was used to monitor the OTA level in red wine samples without any special pretreatment and with satisfactory results obtained. Study results showed that this electrochemical aptasensor could be a potential useful platform for on-site OTA measurement in real complex samples.     

Label-free Electrochemical Aptasensor for the Determination of Serotonin

A label-free electrochemical aptasensor was fabricated for the determination of serotonin (5-HT) by the employment of specific binding between 5-HT and aptamer and directly electrochemical measurement of 5-HT oxidation. The comparison between two aptasensors and two strategies was studied. An electrochemical aptasensor fabricated using 57-mer aptamer was facilely used to determine 5-HT in the range from 1 μM to 100 μM with detection limit of 0.3 μM via one step recognition and detection. This work demonstrates that electrochemical method combing aptamer recognition and 5-HT oxidation provides an alternative and promising method for the determination of 5-HT with good selectivity and simplicity.     

A label free aptasensor for Ochratoxin A detection in cocoa beans: An application to chocolate industries

Contamination of food by mycotoxin occurs in minute/trace quantities. Nearly 92.5% of the cocoa samples present Ochratoxin A (OTA) levels at trace quantity. Hence, there is a necessity for a highly sensitive and selective device that can detect and quantify these organic toxins in various matrices such as cocoa beans. This work reports for the first time, a facile and label-free electrochemical impedimetric aptasensor for rapid detection and quantitation of OTA in cocoa beans. The developed aptasensor was constructed based on the diazonium-coupling reaction mechanism for the immobilization of anti-OTA-aptamer on screen printed carbon electrodes (SPCEs). The aptasensor exhibited a very good limit of detection (LOD) as low as 0.15 ng/mL, with added advantages of good selectivity and reproducibility. The increase in electron transfer resistance was linearly proportional to the OTA concentration in the range 0.15–2.5 ng/mL, with an acceptable recovery percentage (91–95%, RSD = 4.8%) obtained in cocoa samples. This work can facilitate a general model for the detection of OTA in cocoa beans based on the impedimetric aptasensor. The analysis can be performed onsite with pre-constructed and aptamer modified electrodes employing a portable EIS set up.     

Advantages of Carbon Nanomaterials in Electrochemical Aptasensors for Food Analysis

Electrochemical aptasensors appear as promising tools in food analysis, able to provide sensitive, fast and cost‐effective analysis, with the added advantage of portability. Carbon nanomaterials and in particular carbon nanotubes and graphene are among the nanomaterials most often used to build electrochemical aptasensors due to their good electrical conductivity, large surface area and multiple functionalisation possibilities. This review aims to give an overview of the types of carbon nanomaterials and their composites which have been used to enhance the performance of electrochemical aptasensors. Examples are detailed for the biosensors which were tested with real food samples. In these aptasensors, carbon nanomaterials have played different roles, from facilitating the immobilization of high amounts of aptamer and enhancing the electroactive area of the sensors to roles as nanocarrier for signaling probes in amplification schemes or even as electroactive probes generating the output signal. The survey of recent literature shows a positive evolution towards increased aptasensor testing with food samples. However, many challenges remain related to the better characterization of nanomaterials used, clarifying the roles of specific components in multi‐component nanocomposites and widening the types of food matrices and analytes tested with the aptasensors. Although we are still far from knowing when these novel tools will replace classic analytical methods in food analysis, carbon nanomaterials will certainly continue to play an important role in the design of future electrochemical aptasensors for food analysis.     

基于铁氰化镍的非标记型核酸适配体电化学传感器检测凝血酶

在玻碳电极（GCE）表面首先用增敏作用的多壁碳纳米管(MWCNTs)夹心于两层电沉积的铁氰化镍（NiHCF）氧化还原电化学探针之间,然后以金纳米粒子为固定核酸适配体的载体,构建了检测凝血酶的非标记型核酸适配体生物传感器。 利用扫描电子显微镜(SEM)对MWCNTs和NiHCF的形貌进行了表征。 利用电化学阻抗谱对传感器的组装过程进行了监测,用循环伏安法（CV）和差分脉冲伏安法（DPV）对传感器的电化学行为进行了研究。 以铁氰化镍为探针的传感器对凝血酶的检测在1.0 ng/L~1.0 mg/L范围内呈良好的线性关系,相关系数为0.998,检测限为0.2 ng/L(S/N=3)。     

Amplified impedimetric aptasensor based on gold nanoparticles covalently bound graphene sheet for the picomolar detection of ochratoxin A

An amplified electrochemical impedimetric aptasensor for ochratoxin A (OTA) was developed with picomolar sensitivity. A facile route to fabricate gold nanoparticles covalently bound reduced graphene oxide (AuNPs–rGO) resulted in a large number of well-dispersed AuNPs on graphene sheets with tremendous binding sites for DNA, since the single rGO sheet and each AuNP can be loaded with hundreds of DNA strands. An aptasensor with sandwich model was fabricated which involved thiolated capture DNA immobilized on a gold electrode to capture the aptamer, then the sensing interface was incubated with OTA at a desired concentration, followed by AuNPs–rGO functionalized reporter DNA hybridized with the residual aptamers. By exploiting the AuNPs–rGO as an excellent signal amplified platform, a single hybridization event between aptamer and reporter DNA was translated into more than 10⁷ redox events, leading to a substantial increase in charge-transfer resistance (R_ct) by 7∼ orders of magnitude compared with that of the free aptamer modified electrode. Such designed aptasensor showed a decreased response of R_ct to the increase of OTA concentrations over a wide range of 1 pg mL⁻¹–50 ng mL⁻¹ and could detect extremely low OTA concentration, namely, 0.3 pg mL⁻¹ or 0.74 pM, which was much lower than that of most other existed impedimetric aptasensors. The signal amplification platform presented here would provide a promising model for the aptamer-based detection with a direct impedimetric method.