Recent advances of nanomaterial-based optical sensor for the detection of benzimidazole fungicides in food: a review

Nano-interface enhanced electrochemical sensing of hazardous organochlorine pesticides and prospects with ZnO based nanomaterials

Detection and analysis of organochlorine pesticides (OCP) residue is getting significant research importance because of their extensive use despite their hazardous effects on the health of people and the ecosystem. Despite the implementation of regulations and bans to safeguard human health and the environment, reports frequently reveal the continued use of these harmful chemicals in quantities exceeding the recommended limits set by regulatory boards. Data on the use of OCP from India, the most populous country, and African countries is not very encouraging. Conventional methods used for pesticide identification rely on high-cost and bulky instruments, which are also time-consuming and resource-intensive. Therefore, a low-cost, simple, easy-to-handle, and portable pesticide detection device is the need of the hour to enhance the convenience of routine detection and analysis. Nanomaterial-based sensors, composed of metal oxides, polymers, metals, enzyme-functionalized nanostructures, and nanocomposites, hold significant potential for monitoring pesticides, even at extremely low levels, and offer a unique alternative to traditional detection methods. This study examines the potential health risks associated with OCP residues and commonly used analytical techniques for pesticide detection. It also thoroughly examines the latest developments in nanomaterial-based electrochemical sensors, specifically focusing on ZnO-based nanomaterials for OCP detection. Researchers have successfully experimented with ZnO nanomaterials for pesticide degradation, in addition to their use in detection. This review provides a summary of the detection limits, linear ranges, and various fabrication methods of these developed sensors. It also addresses the practicality issues and detection strategies, thereby providing a comprehensive overview of the state of the art in OCP detection using nanomaterials. Furthermore, this review provides insights on potential future perspectives in the area from the authors' standpoint.

Electrochemical Sensing toward Noninvasive Evaluation of High-Starch Food Digestion via Point-of-Use Monitoring Glucose Level in Saliva

To provide individuals with healthier and more reliable dietary recommendations for diabetic patients, a pragmatic electrochemical sensing toward in situ monitoring of glucose in saliva was designed for noninvasive evaluation of high-starch food digestion. The proposed sensor was constructed by exploiting a carbon-based nanostructure for electrical conductivity and Ni-based nanozyme toward direct catalytic oxidation of glucose for signal output. Particularly, the catalytic host-guest interaction between nanozyme and glucose was investigated to be a hydrogen bond via molecular docking, and the C11 and O5 sites in the glucose molecule were attacked during host-guest catalytic reaction through density functional theory (DFT) research. With merits of simplicity, sensitivity, and accuracy, the electrochemical sensor exhibited good performance for monitoring glucose with a detection limit of 10 μM (corresponding to 1.8 μg mL-1). Moreover, it was well qualified to point-of-use trace glucose levels in saliva, offering a promising tool for noninvasive evaluation of high-starch food digestion (e.g., Wheat bread, Steamed bun, and Shao-mai) at different times after meals and eventually yielding benefits to dietary recommendations for diabetic patients.

Recent Advances in Food Safety: Nanostructure-Sensitized Surface-Enhanced Raman Sensing

Food safety is directly related to human health and has attracted intense attention all over the world. Surface-enhanced Raman scattering (SERS), as a rapid and selective technique, has been widely applied in monitoring food safety. SERS substrates, as an essential factor for sensing design, greatly influence the analytical performance. Currently, nanostructure-based SERS substrates have garnered significant interest due to their excellent merits in improving the sensitivity, specificity, and stability, holding great potential for the rapid and accurate sensing of food contaminants in complex matrices. This review summarizes the fundamentals of Raman spectroscopy and the used nanostructures for designing the SERS platform, including precious metal nanoparticles, metal-organic frameworks, polymers, and semiconductors. Moreover, it introduces the mechanisms and applications of nanostructures for enhancing SERS signals for monitoring hazardous substances, such as foodborne bacteria, pesticide and veterinary drug residues, food additives, illegal adulterants, and packaging material contamination. Finally, with the continuous progress of nanostructure technology and the continuous improvement of SERS technology, its application prospect in food safety testing will be broader.

Synergistic SERS enhancement of NiCo-LDHs microurchins and silver nanoparticles for ultra-sensitive and reusable detection of thiabendazole

Two-dimensional layered semiconductor materials as a distinctive class of materials are comprehensively explored for widespread applications due to narrow bandgap, controllable morphology, and tunable metal cation composition. Herein, we constructed a sensing platform of surface enhanced Raman spectroscopy (SERS) by combination of nickel‑cobalt layered double hydroxide (NiCo-LDH) microurchins and plasmonic silver nanoparticles (Ag NPs) for fungicide detection of thiabendazole (TBZ). The NiCo-LDHs/Ag-NPs microcomposites consist of NiCo-LDHs microurchins having a large number of nanoneedles deposited with photoreduced Ag NPs. The SERS platform with NiCo-LDHs/Ag-NPs shows an excellent SERS performance for TBZ detection, including an ultra-low detection limit of 1.49 × 10-11 M, a sublime enhancement factor of 1.71 × 109, high uniformity, good reproducibility, and long-term storage stability. The ultrahigh SERS activity of NiCo-LDH/Ag-NPs can be attributed to strong electromagnetic enhancement in the nanoscale gaps between Ag NPs, massive charge transfer through large-area NiCo-LDH/Ag-NPs interfaces, and the synergistic action of electromagnetic and charge transfer mechanisms. Besides, the unique morphology of NiCo-LDHs/Ag-NPs microcomposite provides a broad surface area for adsorption of TBZ molecules for further Raman signal enhancement. The practicability of the proposed SERS platform is confirmed by detecting TBZ in the real samples of apple juice and river water. The exceptional self-cleaning capability of the NiCo-LDHs/Ag-NPs microcomposite with an retention rate of 81.97 % even after the fifth degradation cycle underscores its impressive sustainable reusability and cost-effectiveness. The findings in this work lay the foundation for the development of high-performance SERS platforms to ensure food safety and environmental protection.

The Evaluation of a Lateral Flow Strip Based on the Covalently Fixed "End-On" Orientation of an Antibody for Listeria monocytogenes Detection

In this study, the covalently fixed "end-on" orientation of a monoclonal Listeria monocytogenes antibody (mAb-Lis) to amino terminated oligo (ethylene glycol)-capped gold nanoparticles (NH2-TEG-AuNPs) was used to fabricate an in-house lateral flow strip (LFS), namely, the fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS. The aim was to evaluate the performance of the fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS in detecting L. monocytogenes. The proposed LFS enabled the sensitive detection of L. monocytogenes in 15 min with a visual limit of detection of 102 CFU/mL. Quantitative analysis indicated an LOD at 10 CFU/mL. The fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS showed no cross-reactivity with other pathogenic bacteria and practical performance across different food matrices, including human blood, milk, and mushroom samples. Furthermore, the clinical performance of the fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS for detecting L. monocytogenes was evaluated by using 12 clinical samples validated by the hemoculture method. It demonstrated excellent concordance with the reference methods, with no false-positive or false-negative results observed. Therefore, the fixed "end-on" Lis-mAb-NH-TEG-AuNPs LFS serves as a promising candidate for a point-of-care test (POCT), enabling the rapid, precise, and highly sensitive detection of L. monocytogenes in clinical samples and contaminated food.

Carbon-Based Electrochemical (Bio)sensors for the Detection of Carbendazim: A Review

Carbendazim, a fungicide widely used in agriculture, has been classified as a hazardous chemical by the World Health Organization due to its environmental persistence. It is prohibited in several countries; therefore, detecting it in food and environmental samples is highly necessary. A reliable, rapid, and low-cost method uses electrochemical sensors and biosensors, especially those modified with carbon-based materials with good analytical performance. In this review, we summarize the use of carbon-based electrochemical (bio)sensors for detecting carbendazim in environmental and food matrixes, with a particular interest in the role of carbon materials. Focus on publications between 2018 and 2023 that have been describing the use of carbon nanotubes, carbon nitride, graphene, and its derivatives, and carbon-based materials as modifiers, emphasizing the analytical performance obtained, such as linear range, detection limit, selectivity, and the matrix where the detection was applied.

Hybridizing aggregated gold nanoparticles with a hydrogel to prepare a flexible SERS chip for detecting organophosphorus pesticides

A simple method has been developed to hybridize aggregated gold nanoparticles with a hydrogel for novel hydrogel SERS chips with high sensitivity, good repeatability, long-term stability, and strong anti-interference ability.