Current development of microfluidic immunosensing approaches for mycotoxin detection via capillary electromigration and lateral flow technology

Mycotoxin contamination in the food chain has caused serious health issues in humans and animals. Thus, a rapid on-site and lab-independent detection method for mycotoxins, such as aflatoxins (AFTs), is desirable. Microfluidic chip based immunosensor technology is one of the most promising methods for fast mycotoxin assays. In this review, we cover the major microfluidic immunosensors used for mycotoxin analysis, via flow-through (capillary electromigration) and lateral flow technology. Sample preparation from different matrices of agricultural products and foodstuffs is summarized. The choice of materials, fabrication strategies, and detection methods for microfluidic immunosensors are further discussed in detail. The sensors application in mycotoxin determination is also outlined. Finally, future challenges and opportunities are discussed.     

Immunochemical tools for mycotoxin detection in food

Abstract  

As a result of the deleterious effects of mycotoxins on human and animal health, and the consequently increasing stringency in the determination of food contamination levels, many researchers have focused their efforts on developing new devices for the detection of these compounds. Biosensors merit special mention due to their sensitivity, accuracy, cost-effectiveness and simplicity, not only of the construction, but also of the sample pre-treatment, if necessary, and the measurement step. Furthermore, biosensor arrays offer additional advantages, such as the possibility to measure multiple samples and provide multi-mycotoxin profiles in one assay. In this case, apart from shortening the analysis time, accuracy is improved by the assessment of matrix interferences and synergistic effects among mycotoxins. Biosensors and arrays for mycotoxins are thus promising biotechnological tools for mycotoxin detection in food.     

石墨烯吸附材料及其在真菌毒素检测中的应用

石墨烯类纳米材料作为一种近十年来兴起的新型吸附材料,被广泛应用于各种有毒有害物质的去除和检测研究。真菌毒素是污染粮油食品的主要危害因子之一,其检测技术研究常常受样品前处理方法的限制。该文介绍了目前作为吸附剂的石墨烯类纳米材料及其样品前处理技术,总结了其在真菌毒素检测中的最新应用进展。     

Analysis of some metabolites of T-2 toxin, diacetoxyscirpenol and deoxynivalenol by thermospray high-performance liquid chromatography-mass spectrometry

Detection and identification of mycotoxin metabolites is a very challenging task. In order to achieve adequate sensitivity and specificity an analytical technique must overcome serious matrix interferences. Gas chromatography-mass spectrometry (GC-MS) which has the sensitivity and specificity to detect and identify mycotoxin metabolites requires hydrolysis of conjugated metabolites as well as derivatization. Thermospray high-performance liquid chromatography-mass spectrometry (HPLC-MS) offers the sensitivity, specificity, and structural information to detect and identify some mycotoxin metabolites in fecal and urine samples without derivatization. The mycotoxins evaluated in this study include deoxynivalenol (DON), T-2 toxin, and diacetoxyscirpenol. The de-epoxy and hydroxy metabolites of each toxin and the glucuronide conjugate of DON were isolated, extracted, and analyzed to detect their occurrence in animals. The thermospray mass spectra of the toxins showed an [M + H]+ ion and numerous structurally significant fragment ions in the positive ion detection mode. Negative ion detection exhibited primarily [M + acetate]- cluster ions with less fragmentation than observed by positive ion detection. The operation of the interface in the filament-on mode greatly increased the sensitivity in both positive and negative ion detection mode. Detection limits of 50-500 pg injected on column are obtained for these toxins and their metabolites using multiple ion detection. The urine and fecal extracts from rats, hens, and cows did not interfere with the HPLC-MS analysis for the specific metabolites or the glucuronide conjugate.     

Immunochemical tools for mycotoxin detection in food

Abstract  As a result of the deleterious effects of mycotoxins on human and animal health, and the consequently increasing stringency in the determination of food contamination levels, many researchers have focused their efforts on developing new devices for the detection of these compounds. Biosensors merit special mention due to their sensitivity, accuracy, cost-effectiveness and simplicity, not only of the construction, but also of the sample pre-treatment, if necessary, and the measurement step. Furthermore, biosensor arrays offer additional advantages, such as the possibility to measure multiple samples and provide multi-mycotoxin profiles in one assay. In this case, apart from shortening the analysis time, accuracy is improved by the assessment of matrix interferences and synergistic effects among mycotoxins. Biosensors and arrays for mycotoxins are thus promising biotechnological tools for mycotoxin detection in food. Graphical Abstract        

Determination of mycotoxins in human foods

This tutorial review deals with the analytical methods available for the determination of mycotoxins in food commodities. As the secondary metabolites of a range of fungal species, mycotoxins possess diverse chemical structures, presenting analytical chemists with a unique set of challenges in the microg kg(-1) (ppb) range. A number of analytical methods have been applied to mycotoxin analysis. These include widely applicable HPLC methods with UV or fluorimetric detection, which are extensively used both in research and for legal enforcement of food safety legislation and for regulations in international agricultural trade. Other chromatographic methods, such as TLC and GC, are also employed for the determination of mycotoxins, whereas recent advances in analytical instrumentation have highlighted the potential of LC-MS methods, especially for multi-toxin determination and for confirmation purposes. Conventional chromatographic methods are generally time consuming and capital intensive, and hence a range of methods, mostly based on immunological principles, have been developed and commercialised for rapid analysis. These methods include, among others, enzyme-linked immunosorbent analysis (ELISA), direct fluorimetry, fluorescence polarization, and various biosensors and strip methods.     

Mycotoxins Detection Based on Electrochemical Approaches

Electrochemical biosensors have attracted much attention in mycotoxin bioanalysis. In this review, three electrochemical biosensor technologies for mycotoxins were reviewed, including general electrochemistry, photoelectrochemistry, and electrochemiluminescence. Based on the classification of multiple electrochemical detection methods, the design schemes, recognition mechanism and probe materials were described in detail. Moreover, the characteristics and limitations of these electrochemical biosensors were summarized. The challenges and future trends of electrochemical biosensor development in mycotoxin bioanalysis were also briefly discussed in the end. This review is expected to provide some inspirations for point-of-care testing in electrochemical sensors for mycotoxins and further electrochemical analysis application.     

Solid-phase extraction techniques based on nanomaterials for mycotoxin analysis: An overview for food and agricultural products

Mycotoxin contamination is a globally concerned problem for food and agricultural products since it may directly or indirectly induce severe threats to human health. Sensitive and selective screening is an efficient strategy to prevent or reduce human and animal exposure to mycotoxins. However, enormous challenges exist in the determination of mycotoxins, arising from complex sample matrices, trace-level analytes, and the co-occurrence of diverse mycotoxins. Appropriate sample preparation is essential to isolate, purify, and enrich mycotoxins from complicated matrices, thus decreasing sample matrix effects and lowering detection limits. With the cross-disciplinary development, new solid-phase extraction strategies have been exploited and integrated with nanotechnology to meet the challenges of mycotoxin analysis. This review summarizes the advance and progress of solid-phase extraction techniques as the methodological solutions for mycotoxin analysis. Emphases are paid on nanomaterials fabricated as trapping media of solid-phase extraction techniques, including carbonaceous nanoparticles, metal/metal oxide-based nanoparticles, and nanoporous materials. Advantages and limitations are discussed, along with the potential prospects.     

Species-specific optical genosensors for the detection of mycotoxigenic Fusarium fungi in food samples

Plant-pathogenic Fusarium species, Fusarium verticillioides and Fusarium proliferatum, are the major producers of fumonisins which are one of the most common mycotoxins found in maize. Herein, we report the development of specific and sensitive genosensors for detecting these two closely related Fusarium species in food samples. The sensors are based on species-specific capture and detection probes, which bind to the intergenic spacer region of rDNA (IGS). Oligonucleotide functionalized magnetic microbeads are used to capture the target DNA which is then detected using biotinylated detection probes and a streptavidin-coupled label. The developed genosensors had detection limits of 1.8 pM and 3.0 pM for F. proliferatum and F. verticillioides, respectively, using synthetic DNA targets. Furthermore, the biosensors were used to analyze natural fungal contamination of commercial maize samples. After amplification of the genomic DNA the sensors detected the presence of the fungi, in accordance with previous results obtained with PCR. No cross-reactivity between F. verticillioides and F. proliferatum, or other fungi species tested, was observed. The developed biosensors can provide a valuable tool to evaluate the potential for mycotoxin contamination in conditions where detection of mycotoxins directly is challenging.     

电化学发光传感器在农业传感领域中的研究进展

基于电化学发光(ECL)分析法构建的电化学发光传感器具有灵敏度高、背景信号低、操作简单的优点,因此,它在农业、工业、环境、临床和食品等领域具有广泛的应用前景。 本文主要综述了电化学发光传感器检测农药残留和真菌毒素的应用及其相应的检测性能,分析了电化学发光传感器在农业传感领域的研究现状,并阐述了未来电化学发光传感器的发展趋势。     

丝网印刷电极在食品安全检测中的应用进展

食品安全问题一直以来都是被广泛关注的热点,选择成本低、使用方便、灵敏度高的检测手段也就成为了食品安全检测领域中研究的焦点。丝网印刷电极因具有可批量生产、成本低、灵敏度高和一次性可抛等特点,已被广泛应用到食品安全检测中。因此,近年来,关于丝网印刷电极在食品安全检测中的应用研究日益增多,建立了多种类型的电化学传感器。依据电化学传感器的不同类型,综述了丝网印刷电极在食品安全检测中的应用,并对丝网印刷电极的应用前景进行了展望。     

Multi-mycotoxin analysis of animal feed and animal-derived food using LC–MS/MS system with timed and highly selective reaction monitoring

Mycotoxins have the potential to enter the human food chain through carry-over of contaminants from feed into animal-derived products. The objective of the study was to develop a reliable and sensitive method for the analysis of 30 mycotoxins in animal feed and animal-derived food (meat, edible animal tissues, and milk) using liquid chromatography–tandem mass spectrometry (LC–MS/MS). In the study, three extraction procedures, as well as various cleanup procedures, were evaluated to select the most suitable sample preparation procedure for different sample matrices. In addition, timed and highly selective reaction monitoring on LC–MS/MS was used to filter out isobaric matrix interferences. The performance characteristics (linearity, sensitivity, recovery, precision, and specificity) of the method were determined according to Commission Decision 2002/657/EC and 401/2006/EC. The established method was successfully applied to screening of mycotoxins in animal feed and animal-derived food. The results indicated that mycotoxin contamination in feed directly influenced the presence of mycotoxin in animal-derived food.

Open image in new window

Graphical abstract Multi-mycotoxin analysis of animal feed and animal-derived food using LC-MS/MS

     

量子点传感器在有机磷农药残留检测中的应用

有机磷农药作为一种神经毒剂,在过量使用后会造成许多潜在危害,如污染作物、环境以及使人畜中毒等。因此,建立高灵敏、高特异的有机磷农药残留检测方法对于保障食品安全与人体健康具有重要意义。基于量子点的传感器分析检测方法因其具有灵敏度高、特异性强、响应速度快、操作简单等优势,在有机磷农药残留检测方面成为研究热点与发展趋势。本文对国内外近年来量子点传感器在作物、环境以及生物样品中有机磷农药残留检测的应用进展进行了综述,并对该领域的前景进行了展望。     

点击化学在食品安全检测中的应用研究进展

点击化学因具有反应模块化、无有毒有害副产物、反应效率高等出色的反应性能备受关注,是继组合化学之后又一新型合成技术,在材料表面功能化、大分子聚合物的合成、生物标记等领域得到了广泛应用.点击反应试剂的活性基团易于修饰在其他化学基团上,表明点击反应有望作为中间反应介导特定反应的信号转换或放大.近几年出现了大量基于点击化学构建...     

分子印迹-电化学发光技术研究进展

分子印迹-电化学发光技术具有分子印迹技术的高选择性及电化学发光技术的高灵敏性,以及发光易于调控、稳定性好、便于微型化和仪器操作简单等优点,已被广泛地应用于重金属检测、免疫传感技术、基因传感技术、酶传感技术、食品安全与药物分析等领域。该文结合本实验室的研究工作介绍了分子印迹电化学发光传感器的原理和构建思路。在此基础上,着重介绍了分子印迹电化学发光技术在食品安全与药物分析中的应用,并对其今后的研究趋势进行了展望。     

Application of Biomarkers to Assessment of Risk to Human Health from Exposure to Mycotoxins

Mycotoxins, the toxic compounds produced by mold secondary metabolism, represent a relevant source of danger to humans through alimentary channels. Efforts have been made by researchers and by national authorities to assess mycotoxin incidence in food, but often results are to be considered approximate or inaccurate due to the huge difficulties posed by sampling procedures. More recently the evaluation of mycotoxins in biological fluids have been given increasing attention since the results may offer valuable indications, although general on the overall status of mycotoxin contamination in food and feed. The assessment of the degree of exposure to these contaminants in the population or in specific groups can also be pursued. Researches on mycotoxins in biological fluids greatly contribute to clarify the mechanism of health impairment attributable to these toxic compounds and to elucidate the dose–response relationship. Despite the considerable efforts devoted to mycotoxin research in the past few decades, improvements in methodology has to be achieved mainly in sampling procedures and in quality assurance of the laboratories involved in mycotoxin analysis, as well as in the selection of appropriate biomarkers.     

Advances in application of sensors for determination of phthalate esters

Phthalates esters(PAEs) are extensively used as additives for polymers in plastic, particularly in polyvinyl chloride(PVC) and polyethylene terephthalate(PET). These compounds are not part of the polymer chains and can be released easily from products and migrate into beverages and foods that come into direct contact, causing environmental and human health impacts. Simple and rapid detection of such substances is of great significance for ensuring environmental food safety and consumer health. A...     

高灵敏光学和电化学适配体传感器在真菌毒素快速检测中的研究进展

高灵敏的生物传感器在痕量真菌毒素污染的快速检测中备受关注.适配体除具有与抗体类似的高选择性外,还具有可体外合成和易修饰等独特优势,已成为现阶段生物传感器中常用的识别元件.随着指数富集的配体系统进化(SELEX)技术的发展,筛选获得的真菌毒素适配体越来越多,为不同真菌毒素的检测提供了基础条件,而适配体结合现代新型纳米材料...     

A direct assessment of mycotoxin biomarkers in human urine samples by liquid chromatography tandem mass spectrometry

Detection of mycotoxin biomarkers in urine of humans and animals provides a direct approach for assessing exposure to these mycotoxins as opposed to the indirect approach of food analysis, which in most cases is affected by the heterogeneity of the toxin in the food samples. Seven (7) mycotoxins and their metabolites (total 18 analytes) were selected and an LC–MS/MS method for their determination in human urine was developed and validated. The method consisted of direct analysis of two mycotoxin conjugates, deoxynivalenol-glucuronide and zearalenone-glucuronide without beta glucuronidase digestion of the urine samples. Since high method sensitivity is of utmost importance in such study, critical factors which could improve the analyte recovery and method sensitivity were investigated by a D-optimal experimental design. Urine samples (10 mL) were first extracted with 15 mL ethyl acetate/formic acid (99/1, v/v) followed by SAX SPE clean-up of the acidified aqueous fraction. Both extracts were combined and analyzed using an LC–MS/MS system operated in the positive ionization mode. A total run time of 28 min was adopted with all the 18 analytes eluting within 15 min.     

LC-MS/MS-based multibiomarker approaches for the assessment of human exposure to mycotoxins

Mycotoxins are toxic fungal secondary metabolites that frequently contaminate food and feed worldwide, and hence represent a major hazard for food and feed safety. To estimate human exposure arising from contaminated food, so-called biomarker approaches have been developed as a complementary biomonitoring tool besides traditional food analysis. The first methods based on radioimmunoassays and enzyme-linked immunosorbent assays as well as on liquid chromatography were developed in the late 1980s and early 1990s for the carcinogenic aflatoxins and in the last two decades further tailor-made methods for some major mycotoxins have been published. Since 2010, there has been a clear trend towards the development and application of multianalyte methods based on liquid chromatography–electrospray ionization tandem mass spectrometry for assessment of mycotoxin exposure made possible by the increased sensitivity and selectivity of modern mass spectrometry instrumentation and sophisticated sample cleanup approaches. With use of these advanced methods, traces of mycotoxins and relevant breakdown and conjugation products can be quantified simultaneously in human urine as so-called biomarkers and can be used to precisely describe the real exposure, toxicokinetics, and bioavailability of the toxins present. In this article, a short overview and comparison of published multibiomarker methods focusing on the determination of mycotoxins and relevant excretion products in human urine is presented. Special attention is paid to the main challenges when analyzing these toxic food contaminants in urine, i.e., very low analyte concentrations, appropriate sample preparation, matrix effects, and a lack of authentic, NMR-confirmed calibrants and reference materials. Finally, the progress in human exposure assessment studies facilitated by these analytical methods is described and an outlook on probable developments and possibilities is presented.