Evaluation of Inhibition Efficiency for the Detection of Captan, 2,3,7,8-Tetrachlorodibenzodioxin, Pentachlorophenol and Carbosulfan in Water: An Electrochemical Approach

Review on emerging applications of nanobiosensor in food safety

Nanosensors have become an indispensable tool in the food sector due to their specificity and sensitivity. The biosensor consists of a transducer coupled with a biorecognition component to transform biological signal into digital signal. Nanobiosensors have been widely used for sensing toxic chemicals such as pesticide residues and pathogenic microbes owing to their accurate sensitivity in an affordable manner, which gives more hope to the food industry on their applications. It employs nanocarriers to bind to impurities and pollutants, as well as food-borne microorganisms and their resulting toxins, such as mycotoxins. This modern technology ensures food safety in food processing industries. Nowadays, nanoparticle-immobilized sensors act as spot indicators to improve smart food packing technology. Certain types of nanobiosensors are deployed to monitor food product manufacture till packaging and to check the freshness of the product till spoilage identification. They are mainly using enzyme catalysts, which are highly sensitive to extreme environmental conditions. As a result, there is a greater evaluation requirement in nanosensor technology to adopt any temperature, pH, or other difficult parameters. Its stability, while in contact with food substrates, is another criterion that needs to be regularized. Within this framework, this review delves into the latest developments in nanobiosensors and the obstacles encountered during their use across different food industries.

Hydrolysis enabled specific colorimetric assay of carbosulfan with sensitivity manipulation via metal-doped or metal-free carbon nanozyme

Precise determination of the carbamate pesticide carbosulfan is crucial for assessing the associated risks in food and environment. Due to the strong interaction between carbosulfan and target enzyme, current methods primarily depend on the acetylcholinesterase (AChE) inhibition strategy, which generally lacks selectivity. In this study, we propose a nanozyme colorimetric sensor for the specific carbosulfan detection, based on its distinctive hydrolysis property. In contrast to other pesticides, carbosulfan can be hydrolyzed to produce the reductive sulfide compound by the cleavage of N-S bond under acidic condition, thereby significantly hindering the nanozyme-mediated chromogenic reaction. Consequently, the absorbance is significantly correlated with carbosulfan concentration. Furthermore, the influence of nanozyme type is disclosed, and two oxidase-like carbon nanozymes were formulated, namely metal-free NC and metal-based CeO2@NC. However, the distinct active sites significantly impact the proposed sensor. For CeO2@NC-based sensor, the produced sulfide compounds not only poison Ce active site, but also consume the reactive oxygen species, thereby, exhibiting high sensitivity with low detection limit of 3.3 nM. By contrast, the metal-free nature of NC allows the assay to remain unaffected by coordination effects, exhibiting superior anti-interference capability. This work not only offers an efficient alternative to the conventional method for detecting carbosulfan specifically, but also shed light on the role of metal-based or metal-free nanozyme among analytical applications.

Study on the toxic effects of sodium pentachlorophenol (PCP-Na) on razor clam (Sinonovacula constricta)

Currently, research on toxic effects of PCP Na is greatly insufficient. The aim of this study is to explore the toxic effects of PCP-Na for better conducting future work on PCP-Na toxicology. For this purpose, S. constricta adults were exposed to PCP-Na for toxicity testing. The results showed that PCP-Na could easily bioaccumulate in S. constricta and significantly affected both phrase I and II metabolism enzymes. Meanwhile, PCP-Na strongly activated antioxidant system and caused PC, LPO and DNA damage. In addition, neurotoxicity and immunotoxicity of PCP-Na was demonstrated in this study. Interestingly, we observed that PCP-Na significantly affected the expression of genes of electron transport chain and induced key enzymes of glycolysis, indicating that PCP-Na may act as an uncoupler of oxidative phosphorylation, interfering with energy supply and causing energy compensation. This study is the first to fully analyze and provide a new perspective on the toxicity of PCP-Na.

New biorecognition molecules in biosensors for the detection of toxins

Biological and synthetic recognition elements are at the heart of the majority of modern bioreceptor assays. Traditionally, enzymes and antibodies have been integrated in the biosensor designs as a popular choice for the detection of toxin molecules. But since 1970s, alternative biological and synthetic binders have been emerged as a promising alternative to conventional biorecognition elements in detection systems for laboratory and field-based applications. Recent research has witnessed immense interest in the use of recombinant enzymatic methodologies and nanozymes to circumvent the drawbacks associated with natural enzymes. In the area of antibody production, technologies based on the modification of in vivo synthesized materials and in vitro approaches with development of "display "systems have been introduced in the recent years. Subsequently, molecularly-imprinted polymers and Peptide nucleic acid (PNAs) were developed as an attractive receptor with applications in the area of sample preparation and detection systems. In this article, we discuss all alternatives to conventional biomolecules employed in the detection of various toxin molecules We review recent developments in modified enzymes, nanozymes, nanobodies, aptamers, peptides, protein scaffolds and DNazymes. With the advent of nanostructures and new interface materials, these recognition elements will be major players in future biosensor development.

Advances in Microfluidic Paper-Based Analytical Devices for Food and Water Analysis

Food and water contamination cause safety and health concerns to both animals and humans. Conventional methods for monitoring food and water contamination are often laborious and require highly skilled technicians to perform the measurements, making the quest for developing simpler and cost-effective techniques for rapid monitoring incessant. Since the pioneering works of Whitesides' group from 2007, interest has been strong in the development and application of microfluidic paper-based analytical devices (μPADs) for food and water analysis, which allow easy, rapid and cost-effective point-of-need screening of the targets. This paper reviews recently reported μPADs that incorporate different detection methods such as colorimetric, electrochemical, fluorescence, chemiluminescence, and electrochemiluminescence techniques for food and water analysis.