Naked eye sensors for on-site pesticide detection: a review

Contamination by pesticides is known to be one of the major issues that are enormously degrading the quality of food and fodder crops together with increased agricultural, environmental and aquatic pollution. Many analytical and laboratory methods are available for detection of these pesticides in products in order to maintain food security but these methods are not readily accessible to most people including farmers for on-site and onfield detection in the crops. The development of more convenient, fast, and cost-effective methods that can be easily accessed by laymen based on simple paper strips or mobile analyzers etc. are need of the time. This review includes a brief discussion about novel devices which have been introduced in the field for pesticide detection viz. easy to use colorimetric and non-colorimetric detection methods based on various electrochemical and optical sensing strategies. These techniques exhibited promising results in field of on-site pesticide detection owing to their easy production, high sensitivity and readily accessible results obtained with these portable devices. This review further describes emerging prospects, deficits and challenges associated with the application of the aforementioned sensing devices

Metal Nanostructures for Environmental Pollutant Detection Based on Fluorescence

Heavy metal ions and pesticides are extremely dangerous for human health and environment and an accurate detection is an essential step to monitor their levels in water. The standard and most used methods for detecting these pollutants are sophisticated and expensive analytical techniques. However, recent technological advancements have allowed the development of alternative techniques based on optical properties of noble metal nanomaterials, which provide many advantages such as ultrasensitive detection, fast turnover, simple protocols, in situ sampling, on-site capability and reduced cost. This paper provides a review of the most common photo-physical effects impact on the fluorescence of metal nanomaterials and how these processes can be exploited for the detection of pollutant species. The final aim is to provide readers with an updated guide on fluorescent metallic nano-systems used as optical sensors of heavy metal ions and pesticides in water

Sensor technologies for the detection and monitoring of endocrine-disrupting chemicals

Endocrine-disrupting chemicals (EDCs) are a class of man-made substances with potential to disrupt the standard function of the endocrine system. These EDCs include phthalates, perchlorates, phenols, some heavy metals, furans, dimethoate, aromatic hydrocarbons, some pesticides, and per- and polyfluoroalkyl substances (PFAS). EDCs are widespread in the environment given their frequent use in daily life. Their production, usage, and consumption have increased many-fold in recent years. Their ability to interact and mimic normal endocrine functions makes them a potential threat to human health, aquatics, and wild life. Detection of these toxins has predominantly been done by mass spectroscopy and/or chromatography-based methods and to a lesser extent by advanced sensing approaches such as electrochemical and/or colorimetric methods. Instrument-based analytical techniques are often not amenable for onsite detection due to the lab-based nature of these detecting systems. Alternatively, analytical approaches based on sensor/biosensor techniques are more attractive because they are rapid, portable, equally sensitive, and eco-friendly. Advanced sensing systems have been adopted to detect a range of EDCs in the environment and food production systems. This review will focus on advances and developments in portable sensing techniques for EDCs, encompassing electrochemical, colorimetric, optical, aptamer-based, and microbial sensing approaches. We have also delineated the advantages and limitations of some of these sensing techniques and discussed future developments in sensor technology for the environmental sensing of EDCs

A Gold Nanoparticle-Based Molecular Self-Assembled Colorimetric Chemosensor Array for Monitoring Multiple Organic Oxyanions

Determination of oxyanions is of paramount importance because of the essential role they play in metabolic processes involved in various aquatic environmental problems. In this investigation, a novel chemical sensor array has been developed by using gold nanoparticles modified with different chain lengths of aminothiols (AET-AuNPs) as sensing elements. The proposed sensor array provides a fingerprint-like response pattern originating from cross-reactive binding events and capable of targeting various anions, including the herbicide glyphosate. In addition, chemometric techniques, linear discrimination analysis (LDA) and the support vector machine (SVM) algorithm were employed for analyte classification and regression/prediction. The obtained sensor array demonstrates a remarkable ability to determine multiple oxyanions in both qualitative and quantitative analysis. The described methodology could be used as a simple, sensitive and fast routine analysis for oxyanions in both laboratory and field settings. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.2018GXNS-FAA138131; Collaborative Innovation Center for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials in GuangxiAcknowledgments: This work was supported by the Collaborative Innovation Center for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials in Guangxi.Funding: This research was funded by Guangxi Natural Science Foundation Program (2018GXNS-FAA138131)

Supramolecular Luminescent Sensors

There is great need for stand-alone luminescence-based chemosensors that exemplify selectivity, sensitivity, and applicability and that overcome the challenges that arise from complex, real-world media. Discussed herein are recent developments toward these goals in the field of supramolecular luminescent chemosensors, including macrocycles, polymers, and nanomaterials. Specific focus is placed on the development of new macrocycle hosts since 2010, coupled with considerations of the underlying principles of supramolecular chemistry as well as analytes of interest and common luminophores. State-of-the-art developments in the fields of polymer and nanomaterial sensors are also examined, and some remaining unsolved challenges in the area of chemosensors are discussed

Applications of Graphene Quantum Dots in Biomedical Sensors

Due to the proliferative cancer rates, cardiovascular diseases, neurodegenerative disorders, autoimmune diseases and a plethora of infections across the globe, it is essential to introduce strategies that can rapidly and specifically detect the ultralow concentrations of relevant biomarkers, pathogens, toxins and pharmaceuticals in biological matrices. Considering these pathophysiologies, various research works have become necessary to fabricate biosensors for their early diagnosis and treatment, using nanomaterials like quantum dots (QDs). These nanomaterials effectively ameliorate the sensor performance with respect to their reproducibility, selectivity as well as sensitivity. In particular, graphene quantum dots (GQDs), which are ideally graphene fragments of nanometer size, constitute discrete features such as acting as attractive fluorophores and excellent electro-catalysts owing to their photo-stability, water-solubility, biocompatibility, non-toxicity and lucrativeness that make them favorable candidates for a wide range of novel biomedical applications. Herein, we reviewed about 300 biomedical studies reported over the last five years which entail the state of art as well as some pioneering ideas with respect to the prominent role of GQDs, especially in the development of optical, electrochemical and photoelectrochemical biosensors. Additionally, we outline the ideal properties of GQDs, their eclectic methods of synthesis, and the general principle behind several biosensing techniques.DFG, 428780268, Biomimetische Rezeptoren auf NanoMIP-Basis zur Virenerkennung und -entfernung mittels integrierter Ansätz

Biosensors for Environmental Monitoring

Real-time and reliable detection of molecular compounds and bacteria is essential in modern environmental monitoring. For rapid analyses, biosensing devices combining high selectivity of biomolecular recognition and sensitivity of modern signal-detection technologies offer a promising platform. Biosensors allow rapid on-site detection of pollutants and provide potential for better understanding of the environmental processes, including the fate and transport of contaminants.This book, including 12 chapters from 37 authors, introduces different biosensor-based technologies applied for environmental analyses

Nanosensores colorimétricos para la detección rápida de pesticidas organofosforados en sistemas acuosos: materiales y caracterización

No aplicaUna de las estrategias de desarrollo competitivo en el sector agrícola y alimenticio ha sido el uso de agentes químicos como los pesticidas organofosforados OP que aceleran y mejoran los procesos de producción y sustentabilidad de cosechas. Sin embargo, el uso excesivo de estos y la insuficiente normativa para su control a nivel nacional e internacional produce un impacto ambiental y de salud negativo. Sumado a esto, el uso de técnicas analíticas avanzadas y costosas para su determinación, limitan el control de estas sustancias a instituciones con capacidad instalada, dejando de lado a productores y pequeñas empresas. De esta manera, el desarrollo y aplicabilidad de nuevas tecnologías como la “nanotecnología” ha generado alternativas para innovar los procesos de detección de manera rápida y menos costosos a través del diseño de nanosensores. En esta monografía se exponen investigaciones de nanosensores colorimétricos con potencial aplicación en la detección de pesticidas organofosforados en sistemas acuosos, involucrando la estructura, composición y proporciones de los materiales y sus nanoestructuras, variables de importancia para definir su aplicabilidad. Se inicia con revisión en el marco de los contaminantes presentes en estos sistemas, definiciones sobre pesticidas, importancia de la nanotecnología y tipos de nanomateriales utilizados; se continúa con la revisión de varias investigaciones y ensayos realizados sobre nanosensores colorimétricos, técnicas de caracterización y materiales, ventajas y desventajas, y finalmente se evidencia como el desarrollo de la nanotecnología ha contribuido en la creación de técnicas in situ que podrían constituirse en tipos de análisis químicos accesibles y con bajos costos.One of the competitive development strategies in the agricultural and food sector has been the use of chemical agents such as OP organophosphate pesticides that accelerate and improve the production processes and the sustainability of crops. However, the excessive use of these and the insufficient regulations for their control at the national and international levels produce a negative environmental and health impact. Added to this, the use of advanced and expensive analytical techniques for their determination, limit the control of these substances to institutions with installed capacity, leaving aside producers and small businesses. In this way, the development and applicability of new technologies such as "nanotechnology" has generated alternatives to innovate detection processes quickly and less expensively through the design of nanosensors. In this monograph, investigations of colorimetric nanosensors with potential application in the detection of organophosphate pesticides in aqueous systems are exposed, involving the structure, composition and proportions of the materials and their nanostructures, important variables to define their applicability. It begins with a review of the pollutants present in these systems, definitions of pesticides, the importance of nanotechnology and the types of nanomaterials used; It continues with the review of various investigations and tests carried out on colorimetric nanosensors, characterization techniques and materials, advantages and disadvantages, and finally it is shown how the development of nanotechnology has contributed to the creation of in situ techniques that could become types of accessible and low-cost chemical analysis

Label-free and Aptamer-based Surface Enhanced Raman Spectroscopy for Detection of Food Contaminants

The development of analytical methods to detect food contaminants is a critical step for improving food safety. Surface enhanced Raman spectroscopy (SERS) is an emerging detection technology that has the potential to rapidly, accurately and sensitively detect a wide variety of food contaminants. However, SERS detection becomes a challenge in real complex matrix, such as food, since non-specific matrix signals have the potential to drown out target associated Raman peaks. In this dissertation, we focused on the development and application of label-free, aptamer-based SERS in order to improve the accuracy and specificity of target contaminant detection in food. To accomplish this, different types of aptamer-modified SERS substrates (i.e. thiolated or non-thiolated ssDNA aptamers conjugated onto silver dendrites, gold-coated magnetic nanoparticles, gold nanoparticles and gold nanoparticles coated magnetic nanoparticles) were tested in liquid foods (e.g. apple juice and milk) to detect a variety of food contaminants including pesticides, antibiotics and foodborne pathogens. Next, an integration of aptamer-based SERS and aptamer-assisted colorimetric detection was attempted using gold nanoparticles as the substrate to create a rapid detection-validation protocol. Finally, we attempted to create a simple SELEX method that could be used to design aptamers for food safety applications. Our results demonstrate that aptamer-based SERS is capable of detecting a variety of aptamer-specific food contaminants while drastically reducing Raman signal interference from food matrix. Thus, this method shows great potential as a rapid detection method in food, especially since sample extraction procedure can be simplified. Aptamer-based SERS method can also be used to validate results from the gold nanoparticles based colorimetric assays. It can help us understand the intermolecular interactions that govern the mechanism and successful interpretation of the colorimetric results, which can then reduce false positive and false negative results. Lastly, several breakthroughs were achieved using the developed “gold nanoparticle-assisted SELEX” procedure. This is promising to design a wider variety of target specific aptamers without the need for large, specialized equipment. By advancing the completion of this SELEX method, there is great potential for creating more label-free, aptamer-based SERS methods for food contamination detection and to improve food safety as a whole