An impedimetric biosensor based on poly(l-lysine)-decorated multiwall carbon nanotubes for the determination of diazinon in water and fruits

Biosensor Technologies for Water Quality: Detection of Emerging Contaminants and Pathogens

This review explores the development, technological foundations, and applications of biosensor technologies across various fields, such as medicine for disease diagnosis and monitoring, and the food industry. However, the primary focus is on their use in detecting contaminants and pathogens, as well as in environmental monitoring for water quality assessment. The review classifies different types of biosensors based on their bioreceptor and transducer, highlighting how they are specifically designed for the detection of emerging contaminants (ECs) and pathogens in water. Key innovations in this technology are critically examined, including advanced techniques such as systematic evolution of ligands by exponential enrichment (SELEX), molecularly imprinted polymers (MIPs), and self-assembled monolayers (SAMs), which enable the fabrication of sensors with improved sensitivity and selectivity. Additionally, the integration of microfluidic systems into biosensors is analyzed, demonstrating significant enhancements in performance and detection speed. Through these advancements, this work emphasizes the fundamental role of biosensors as key tools for safeguarding public health and preserving environmental integrity.

Pesticide residues and their detection techniques in foods using sensors- a review

The use of pesticides in agricultural produce is continuously increasing and it raises the question of whether the food is safe or not. Only 0.1% of the sprayed pesticide reaches its target and the rest acts as a contaminant in soil and the environment, thus contaminating the future foods as well. The pesticide residue management is gaining attention as pesticide poisoning account for more than 3.5% of total deaths. The use of pesticides needs to be checked and applied in a controlled manner. Easy and rapid methods for the quantification of pesticides in foods need to be developed. In the present review, details about pesticides have been described in the first part. Secondly, the techniques and recent developments for the detection of pesticides have been summarized and finally, the emerging challenges and future perspectives for pesticide handling has been discussed with special emphasis on the use of Nano-sensors for pesticide detection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-06116-8.

Fabrication of a ZnFe2O4@Co/Ni-MOF nanocomposite and photocatalytic degradation study of azo dyes

This study addresses the critical issue of removing organic pollutants from water, focusing on the photocatalytic degradation of Congo red (CR) dye using a novel ZnFe2O4@Co-Ni metal-organic framework (MOF) nanocomposite (ZFCNM). The primary aim was to develop a photocatalyst with enhanced efficiency by combining the properties of ZnFe2O4 with Co/Ni-MOF, leading to a low band gap (2.89 eV) and a high surface area (723 m2 g-1). The ZFCNM nanocomposite, synthesized via a hydrothermal method, was characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), confirming the formation of face-centered cubic ferrite and hexagonal MOF structures. Fourier-transform infrared spectroscopy (FTIR) verified the presence of carboxyl (-COOH) groups and Fe-O bonds in the composite. Photodegradation efficiency was evaluated under varying conditions, including reaction time, pH, catalyst dosage, contaminant concentration, and light intensity. The ZFCNM photocatalyst, with an equal mass ratio of Co/Ni-MOF and ZnFe2O4, achieved a 98% removal efficiency of CR (75 min reaction time, pH 5, at 25 °C, and visible-light intensity of a 50 W LED lamp) significantly outperforming Co/Ni-MOF (24%) and ZnFe2O4 (36%) alone. The estimated quantum yield (QY) was 3.00 × 10-6 molecules per photon, and kinetic studies revealed a first-order reaction pathway with an R 2 value of 0.9813. These results highlight the potential of ZFCNM as an effective photocatalyst for water purification applications.

Recent Advances in Nanomaterial-Based Biosensors for Pesticide Detection in Foods

Biosensors are a simple, low-cost, and reliable way to detect pesticides in food matrices to ensure consumer food safety. This systematic review lists which nanomaterials, biorecognition materials, transduction methods, pesticides, and foods have recently been studied with biosensors associated with analytical performance. A systematic search was performed in the Scopus (n = 388), Web of Science (n = 790), and Science Direct (n = 181) databases over the period 2016–2021. After checking the eligibility criteria, 57 articles were considered in this study. The most common use of nanomaterials (NMs) in these selected studies is noble metals in isolation, such as gold and silver, with 8.47% and 6.68%, respectively, followed by carbon-based NMs, with 20.34%, and nanohybrids, with 47.45%, which combine two or more NMs, uniting unique properties of each material involved, especially the noble metals. Regarding the types of transducers, the most used were electrochemical, fluorescent, and colorimetric, representing 71.18%, 13.55%, and 8.47%, respectively. The sensitivity of the biosensor is directly connected to the choice of NM and transducer. All biosensors developed in the selected investigations had a limit of detection (LODs) lower than the Codex Alimentarius maximum residue limit and were efficient in detecting pesticides in food. The pesticides malathion, chlorpyrifos, and paraoxon have received the greatest attention for their effects on various food matrices, primarily fruits, vegetables, and their derivatives. Finally, we discuss studies that used biosensor detection systems devices and those that could detect multi-residues in the field as a low-cost and rapid technique, particularly in areas with limited resources.

Emerging vistas on pesticides detection based on electrochemical biosensors - An update

Organophosphates and carbamates pesticides are widely used to increase crop production globally causing a threat to human health and the environment. A variety of pesticides are applied during different stages of vegetable production. Therefore, monitoring the presence of pesticide residues in food and soil has great relevance to sensitive pesticide detection through distinct determination methods that are urgently required. Conventional techniques for the detection of pesticides have several limitations that can be overcome by the development of highly sensitive, fast, reliable and easy-to-use electrochemical biosensors. Herein, we describe the types of biosensors with the main focus on electrochemical biosensors fabricated for the detection of OPPs and carbamates pesticides. An overview of conventional techniques employed for pesticide detection is also discussed. This review aims to provide a glance of recently developed biosensors for some common pesticides like chlorpyrifos, malathion, parathion, paraoxon, and carbaryl which are present in food and environment samples.

Fabrication of Template-Less Self-Propelled Micromotors Based on A Metal-Sandwiched Polytryptophan Body: An Experimental and DFT Study

The diverse capabilities of self-propelled micro/nanomotors open up significant opportunities for various environmental and biomedical applications. Here, a synchronized two-lobed bubble exhaust drives micromotor comprising a metal (cobalt and gold) sandwiched polytryptophan body (Au/poly-Trp/Co) in a non-curved direction. The autonomous motion is achieved through the decomposition of chemical fuel to result in a kayak-like system. The ejected oxygen bubbles from the interfacial cobalt/polytryptophan layer, as well as the inert nature of the metal segments (Au-Co), were considered for some computational studies of the electronic properties of the composite and physical phenomena at the kayak/electrolyte interfaces, and confirmed the role of Co-Trp in the fuel decomposition. It is believed that the autonomous motion is the combined result of bubble recoil force, self-electrophoresis, and perturbation in the interfacial hydrogen-bond network of the poly-Trp body and water molecules. The velocity of the micromotor in the range 23±4 to 157±17 μm s^-1 at different concentrations of H₂ O₂ from 1 % to 10 %. Depending on the method of fragmentation, it is possible to have both single and multiple motorized kayaks with lengths of 1.5 and 6 μm, respectively, that can be tailored for environmental applications.