Electrochemical biosensors for food analysis

Abstract  Food analysis has become a very important and interesting area of research because of the rapid expansion of food trade and highly increased mobility of today’s populations. Food quality control is essential both for consumer protection and also for the food industry. Application of the electrochemical biosensors in the field of food analysis is promising. This review covers the recent developments and issues in electrochemical biosensors for food analysis, such as ease of preparation, robustness, sensitivity, and realization of mass production of the detection strategies. This review also emphasizes the current development of electrochemical biosensors combined with nanotechnology. Graphical abstract        

Breath biosensing: using electrochemical enzymatic sensors for detection of biomarkers in human breath

Detection of biomarkers for disease by noninvasive methods is critical for the early diagnosis and screening of disease, enabling prompt treatment. Breath biosensors are a viable option as the exhaled breath contains several biomarkers linked to lung cancer, oxidative stress, diabetes, and other diseases. Breath analysis has been achieved by advanced analytical techniques such as gas chromatography and infrared spectroscopy. However, electrochemical enzymatic breath biosensors offer a cost-effective, sensitive platform for biomarker detection without complex analysis and interpretation by trained laboratory personnel. This review aims to summarize recent advances in the field of electrochemical enzymatic breath biosensors and offer future opportunities from other applications of nonelectrochemical enzymatic breath biosensors.     

Electrochemical biosensors for food analysis

Abstract  

Food analysis has become a very important and interesting area of research because of the rapid expansion of food trade and highly increased mobility of today’s populations. Food quality control is essential both for consumer protection and also for the food industry. Application of the electrochemical biosensors in the field of food analysis is promising. This review covers the recent developments and issues in electrochemical biosensors for food analysis, such as ease of preparation, robustness, sensitivity, and realization of mass production of the detection strategies. This review also emphasizes the current development of electrochemical biosensors combined with nanotechnology.     

电化学生物传感器在污水分析及污水流行病学中的应用进展

近年来,污水流行病学（wastewater-based epidemiology, WBE）已被证明是用来监测社区毒品滥用和公共健康的一种有效评估方法,该方法通过定量分析指定社区污水回收站中污水的药物残留或者代谢物来反推社区中人们对毒品的消耗量并结合指定社区的人口数量对其进行归一化处理. 电化学生物传感器具有响应时间快、成本低、分析样品需求量小、数据分辨率高以及能够现场快速测试等特点,已被广泛应用于疾病快速诊断、环境污染监测、食品安全以及毒品检测等领域. 液相色谱-质谱联用是分析污水中的毒品及其代谢物的主要方法,但随着传感技术尤其是电化学传感器近来的快速发展,也开始被用于研究污水传染病学并可实现现场快速测量. 本文综述了电化学生物传感器在污水中无机污染物（如重金属）、有机污染物（如农药、毒品）、生物分子（如 DNA）以及细菌等微生物分析中的最新进展,同时还论述了目前电化学传感器技术在污水流行病学领域的应用和未来所面临的主要挑战.     

Biosensors for the analysis of food- and waterborne pathogens and their toxins

Biosensors are devices which combine a biochemical recognition element with a physical transducer. There are various types of biosensors, including electrochemical, acoustical, and optical sensors. Biosensors are used for medical applications and for environmental testing. Although biosensors are not commonly used for food microbial analysis, they have great potential for the detection of microbial pathogens and their toxins in food. They enable fast or real-time detection, portability, and multipathogen detection for both field and laboratory analysis. Several applications have been developed for microbial analysis of food pathogens, including E. coli O157:H7, Staphylococcus aureus, Salmonella, and Listeria monocytogenes, as well as various microbial toxins such as staphylococcal enterotoxins and mycotoxins. Biosensors have several potential advantages over other methods of analysis, including sensitivity in the range of ng/mL for microbial toxins and <100 colony-forming units/mL for bacteria. Fast or real-time detection can provide almost immediate interactive information about the sample tested, enabling users to take corrective measures before consumption or further contamination can occur. Miniaturization of biosensors enables biosensor integration into various food production equipment and machinery. Potential uses of biosensors for food microbiology include online process microbial monitoring to provide real-time information in food production and analysis of microbial pathogens and their toxins in finished food. Biosensors can also be integrated into Hazard Analysis and Critical Control Point programs, enabling critical microbial analysis of the entire food manufacturing process. In this review, the main biosensor approaches, technologies, instrumentation, and applications for food microbial analysis are described.     

Recent advances in bioelectrochemical detection of E. coli bacteria in saline buffers and spiked real samples using traditional and nanostructured active substrates

A rapid and cost-effective method to specifically identify and quantify pathogenic Escherichia coli (E. coli) bacteria in aqueous samples and food products is highly recommended to avoid the degradation of human health that can unfortunately lead to fatal cases. To overcome these borderline situations, portable and easy-to-use screening devices are needed for the non-expert public and confirmed by medical personnel/physicians who can quickly guide/prescribe antibiotic treatments. In such a context, nanotechnologies are very promising and useful tools due to the remarkable optical, chemical and physical properties of biocompatible nanomaterials deposited or synthesized on traditional solid electrodes that greatly improve the detection limit and the selectivity of nanostructured-based biosensors. With this in mind, this review summarizes the latest advances in the bioelectrochemical detection of E. coli and its related products using different biosensor configurations in saline buffers and spiked real samples, namely food products (milk, fruits, vegetables), body fluids (blood, urine, swine feces) and river water.     

Arginine-hydrolyzing enzymes for electrochemical biosensors

Since l-Arginine (Arg) is a semi-essential amino acid for humans, its adequate amount must be consumed in the diet to prevent certain negative consequences related to insufficient synthesis of this amino acid under specific physiological conditions. Arg metabolism results in the production of a biochemically diverse range of such products as urea, some amino acids, creatine, polyamines, nitric oxide, etc. Arg, an important biomarker in clinical diagnostics, is also used for prevention/treatment of different diseases, including cancer and COVID-19. Furthermore, it serves as an indicator of food and beverages quality.A variety of optic and electrochemical methods for Arg determination have already been suggested. The biosensor systems based on the enzymes of Arg metabolism were shown to be the most promising tools for Arg assay. This review focuses on the peculiarities of electrochemical biosensors for Arg assay based on the use of Arg-degrading enzymes and on the analysis of their advantages as compared to other approaches.     

Recent developments, characteristics, and potential applications of electrochemical biosensors.

The objective of this study is to analyze the technical importance, performance, techniques, advantages, and disadvantages of the biosensors in general and of the electrochemical biosensors in particular. A product of reaction diffuses to the transducer in the first generation biosensors (based on Clark biosensors). The mediated biosensors or second generation biosensors use specific mediators between the reaction and the transducer to improve sensitivity. The second generation biosensors involve two steps: first, there is a redox reaction between enzyme and substrate that is reoxidized by the mediator, and eventually the mediator is oxidized by the electrode. No normal product or mediator diffusion is directly involved in the third generation biosensors, direct biosensors. Based on the type of transducer, current biosensors are divided into optical, mass, thermal, and electrochemical sensors. They are used in medical diagnostics, food quality controls, environmental monitoring, and other applications. These biosensors are also grouped under two broad categories of sensors: direct and indirect detection systems. Moreover, these systems could be further grouped into continuous or batch operation. Therefore, amperometric biosensors and their current applications are focused on more in detail since they are the most commonly used biosensors in monitoring and diagnosing tests in clinical analysis. Problems related to the commercialization of medical, environmental, and industrial biosensors as well as their performance characteristics, their competitiveness in comparison to the conventional analytical tools, and their costs determine the future development of these biosensors.     

Electrochemical assays for microbial analysis: how far they are from solving microbiota and microbiome challenges

Bacterial sensors are indispensable in environmental monitoring, analysis of food and drink safety, prevention and treatment of pathogenic infections, antibiotic resistance screening, in combatting biocorrosion, and in biodefense. Recent discoveries within Human Microbiome project disclosed vital bacteria's role in human health and disease prognosis and treatment; they also placed in focus new analytical tools for bacterial analysis. Here, I discuss several basic concepts underlying the electrochemical bacterial biosensors: metabolic sensors, biosensors for DNA and RNA extracted from bacterial cells, and whole bacterial cell sensors, and their contribution to practically sought solutions for bacterial analysis. Current analytical issues and perspectives are outlined.     

Stabilized Lipid Films in Electrochemical Biosensors

Lipid membrane based electrochemical biosensors have been exploited for the last 40 years. However, a major obstacle that limited their applications and commercialization was their fragility. Recent advances in stabilization of lipid membranes have tremendously increased the number of publications in the last 5 years. The objective of the present article is to present procedures for the stabilization of lipid film biosensors and recent advances in their analytical uses. These novel devices are used as chemo‐ and biosensors for the quantification of environmental contaminants and food toxicants. Recent research is directed to the construction of a portable mini electrochemical device that will be commercialized and readily be used by non‐skilled personnel for in the field measurements.     

DNA electrochemical biosensors

Disposable electrochemical DNA-based biosensors are reviewed; they have been used for the determination of low-molecular weight compounds with affinity for nucleic acids and for the detection of the hybridisation reaction. The first application is related to the molecular interaction between surface-linked DNA and the target pollutants or drugs, in order to develop a simple device for rapid screening of toxic or similar compounds. The determination of such compounds was measured by their effect on the oxidation signal of the guanine peak of calf thymus DNA immobilised on the electrode surface and investigated by chronopotentiometric analysis. The DNA biosensor is able to detect known intercalating compounds, such as daunomycin, polychlorinated biphenyls (PCBs), aflatoxin B1, and aromatic amines. Applicability to river and waste water samples is also demonstrated. Disposable electrochemical sensors for the detection of a specific sequence of DNA were realised by immobilising synthetic single-stranded oligonucleotides onto a graphite screen-printed electrode. The probes became hybridised with different concentrations of complementary sequences present in the sample. The hybrids formed on the electrode surface were evaluated by chronopotentiometric analysis using daunomycin as indicator of the hybridisation reaction. The hybridisation was also performed using real samples. Application to apolipoprotein E (ApoE) is described, in this case samples have to be amplified by PCR and then analysed by DNA biosensor. The extension of such procedures to samples of environmental interest or to contamination of food is discussed.     

Nanobioelectroanalysis Based on Carbon/Inorganic Hybrid Nanoarchitectures

The emergence of nanotechnology has opened new horizons for electrochemical biosensors. This review highlights new concepts for electrochemical biosensors based on different carbon/inorganic hybrid nanoarchitectures. Particular attention will be given to hybrid nanostructures involving 1‐ or 2‐dimensional carbon nanotubes or graphene along with inorganic nanoparticles (gold, platinum, quantum dot (QD), metal oxide). Latest advances (from 2007 onwards) in electrochemical biosensors based on such hybrids of carbon/inorganic‐nanomaterial heterostructures are discussed and illustrated in connection to enzyme electrodes for blood glucose or immunoassays of cancer markers. Several strategies for using carbon/inorganic nanohybrids in such bioaffinity and biocatalytic sensing are described, including the use of hybrid nanostructures for tagging or modifying electrode transducers, use of inorganic nanomaterials as surface modifiers along with carbon nanomaterial label carriers, and carbon nanostructure‐based electrode transducers along with inorganic amplification tags. The implications of these nanoscale bioconjugated hybrid materials on the development of modern electrochemical biosensors are discussed along with future prospects and challenges.     

Electrochemical Biosensors for Detection of Biological Warfare Agents

This review discusses current development in electrochemical biosensors for detection of biological warfare agents. This could include bacteria, viruses and toxins that are aerosoled deliberately in air, food or water to spread terrorism and cause disease or death to humans, animals or plants. The rapid and unequivocal detection and identification of biological warfare agents is a major challenge for any government including military, health and other government agents. Reliable, specific characterization and identification of the microorganism from sampling location, either air, water, soil or others is required. This review will survey different types of electrochemical biosensors has been developed based on the following: i) Immunosensors ii) PCR (DNA base Sensor) iii) Bacteria or whole cell sensor and iv) Enzyme sensor. This article gives an overview of electrochemical biosensor for detection of biological warfare agents. Electrochemical biosensors have the advantages of sensitivity, selectivity, to operate in turbid media, and amenable to miniaturization. Recent developments in immunofiltration, flow injection, and flow‐through electrochemical biosensors for bacteria, viruses, and toxin detection are reviewed. The current research and development in biosensors for biological warfare agents detection is of interest to the public as well as to the defense is also discussed.     

Natural and artificial ion channels for biosensing platforms

The single-molecule selectivity and specificity of the binding process together with the expected intrinsic gain factor obtained when utilizing flow through a channel have attracted the attention of analytical chemists for two decades. Sensitive and selective ion channel biosensors for high-throughput screening are having an increasing impact on modern medical care, drug screening, environmental monitoring, food safety, and biowarefare control. Even virus antigens can be detected by ion channel biosensors. The study of ion channels and other transmembrane proteins is expected to lead to the development of new medications and therapies for a wide range of illnesses. From the first attempts to use membrane proteins as the receptive part of a sensor, ion channels have been engineered as chemical sensors. Several other types of peptidic or nonpeptidic channels have been investigated. Various gating mechanisms have been implemented in their pores. Three technical problems had to be solved to achieve practical biosensors based on ion channels: the fabrication of stable lipid bilayer membranes, the incorporation of a receptor into such a structure, and the marriage of the modified membrane to a transducer. The current status of these three areas of research, together with typical applications of ion-channel biosensors, are discussed in this review.     

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...     

Biosensors for the analysis of microbiological and chemical contaminants in food

Increases in food production and the ever-present threat of food contamination from microbiological and chemical sources have led the food industry and regulators to pursue rapid, inexpensive methods of analysis to safeguard the health and safety of the consumer. Although sophisticated techniques such as chromatography and spectrometry provide more accurate and conclusive results, screening tests allow a much higher throughput of samples at a lower cost and with less operator training, so larger numbers of samples can be analysed. Biosensors combine a biological recognition element (enzyme, antibody, receptor) with a transducer to produce a measurable signal proportional to the extent of interaction between the recognition element and the analyte. The different uses of the biosensing instrumentation available today are extremely varied, with food analysis as an emerging and growing application. The advantages offered by biosensors over other screening methods such as radioimmunoassay, enzyme-linked immunosorbent assay, fluorescence immunoassay and luminescence immunoassay, with respect to food analysis, include automation, improved reproducibility, speed of analysis and real-time analysis. This article will provide a brief footing in history before reviewing the latest developments in biosensor applications for analysis of food contaminants (January 2007 to December 2010), focusing on the detection of pathogens, toxins, pesticides and veterinary drug residues by biosensors, with emphasis on articles showing data in food matrices. The main areas of development common to these groups of contaminants include multiplexing, the ability to simultaneously analyse a sample for more than one contaminant and portability. Biosensors currently have an important role in food safety; further advances in the technology, reagents and sample handling will surely reinforce this position.     

Advances in molecular techniques for the detection and quantification of genetically modified organisms

Progress in genetic engineering has led to the introduction of genetically modified organisms (GMOs) whose genomes have been altered by the integration of a novel sequence conferring a new trait. To allow consumers an informed choice, many countries require food products to be labeled if the GMO content exceeds a certain threshold. Consequently, the development of analytical methods for GMO screening and quantification is of great interest. Exponential amplification by the polymerase chain reaction (PCR) remains a central step in molecular methods of GMO detection and quantification. In order to meet the challenge posed by the continuously increasing number of GMOs, various multiplex assays have been developed for the simultaneous amplification and/or detection of several GMOs. Classical agarose gel electrophoresis is being replaced by capillary electrophoresis (CE) systems, including CE chips, for the rapid and automatable separation of amplified fragments. Microtiter well-based hybridization assays allow high-throughput analysis of many samples in a single plate. Microarrays have been introduced in GMO screening as a technique for the simultaneous multianalyte detection of amplified sequences. Various types of biosensors, including surface plasmon resonance sensors, quartz crystal microbalance piezoelectric sensors, thin-film optical sensors, dry-reagent dipstick-type sensors and electrochemical sensors were introduced in GMO screening because they offer simplicity and lower cost. GMO quantification is performed by real-time PCR (rt-QPCR) and competitive PCR. New endogenous reference genes have been validated. rt-QPCR is the most widely used approach. Multiplexing is another trend in this field. Strategies for high-throughput multiplex competitive quantitative PCR have been reported.     

Electrochemical approaches for the detection of amyloid-β, tau,and α-synuclein

According to the World Health Organization, there are 47 million people worldwide who are afflicted with dementia today, and this is expected to rise to 132 million by 2050. Therefore, it is pertinent to develop efficient analytical methods such as electrochemical biosensors to study these disorders and diagnose them early. This review highlights some of the recent key developments in the use of electrochemical biosensors to study the biomarkers related to neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Especially, we focus on the applications of electrochemistry to analyze amyloid-β and tau related to Alzheimer's disease and α-synuclein related to Parkinson's disease.     

Layer-by-layer construction of protein architectures through avidin–biotin and lectin–sugar interactions for biosensor applications

In this review, the preparation and properties of protein architectures constructed by layer-by-layer (LbL) deposition through avidin–biotin and concanavalin A (Con A)–sugar interactions are discussed in relation to their use for optical and electrochemical biosensors. LbL films can be constructed through the alternate deposition of avidin and biotin-labeled enzymes on the surfaces of optical probes and electrodes. The enzymes retain their catalytic activity, resulting in the formation of optical and electrochemical biosensors. Alternatively, Con A can be used to construct enzyme-containing LbL films and microcapsules using sugar-labeled enzymes. Some enzymes such as glucose oxidase and horseradish peroxidase can be used for this purpose without labeling with sugar, because these enzymes contain intrinsic hydrocarbon chains on their molecular surfaces. The Con A/enzyme LbL architectures were successfully used to develop biosensors sensitive to specific substrates of the enzyme. In addition, Con A-based films can be used for the optical and electrochemical detection of sugars.     

Immobilization of E. coli bacteria in three-dimensional matrices for ISFET biosensor design

In recent years, cell-based biosensors (CBBs) have been very useful in biomedicine, food industry, environmental monitoring and pharmaceutical screening. They constitute an economical substitute for enzymatic biosensors, but cell immobilization remains a limitation in this technology. To investigate into the potential applications of cell-based biosensors, we describe an electrochemical system based on a microbial biosensor using an Escherichia coli K-12 derivative as a primary transducer to detect biologically active agents. pH variations were recorded by an ion-sensitive field effect transistor (ISFET) sensor on bacteria immobilized in agarose gels. The ISFET device was directly introduced in 100 ml of this mixture or in a miniaturized system using a dialysis membrane that contains 1 ml of the same mixture. The bacterial activity could be detected for several days. The extracellular acidification rate (ECAR) was analyzed with or without the addition of a culture medium or an antibiotic solution. At first, the microorganisms acidified their micro-environment and then they alkalinized it. These two phases were attributed to an apparent substrate preference of bacteria. Cell treatment with an inhibitor or an activator of their metabolism was then monitored and streptomycin effect was tested.