Graphene-based functional electrochemical sensors for the detection of chlorpyrifos in water and food samples: a review.

Prolonged and excessive use of chlorpyrifos (CPS) has caused severe pollution, particularly in crops, vegetables, fruits, and water sources. As a result, CPS is detected in various food and water samples using conventional methods. However, its applications are limited due to size, portability, cost, etc. In this regard, electrochemical sensors are preferred for CPS detection due to their high sensitivity, reliability, rapid, on-site detection, and user-friendly. Notably, graphene-based electrochemical sensors have gained more attention due to their unique physiochemical and electrochemical properties. It shows high sensitivity, selectivity, and quick response because of its high surface area and high conductivity. In this review, we have discussed an overview of three graphene-based different functional electrochemical sensors such as electroanalytical sensors, bio-electrochemical sensors, and photoelectrochemical sensors used to detect CPS in food and water samples. Furthermore, the fabrication and operation of these electrochemical sensors using various materials (low band gap material, nanomaterials, enzymes, antibodies, DNA, aptamers, and so on) and electrochemical techniques (CV, DPV, EIS, SWV etc.) are discussed. The study found that the electrical signal was reduced with increasing CPS concentration. This is due to the blocking of active sites, reduced redox reaction, impedance, irreversible reactions, etc. In addition, acetylcholinesterase-coupled sensors are more sensitive and stable than others. Also, it can be further improved by fabricating with low band gap nanomaterials. Despite their advantages, these sensors have significant drawbacks, such as low reusability, repeatability, stability, and high cost. Therefore, further research is required to overcome such limitations.

Advances in oligosaccharides production from brown seaweeds: extraction, characterization, antimetabolic syndrome, and other potential applications.

Brown seaweeds are a promising source of bioactive substances, particularly oligosaccharides. This group has recently gained considerable attention due to its diverse cell wall composition, structure, and wide-spectrum bioactivities. This review article provides a comprehensive update on advances in oligosaccharides (OSs) production from brown seaweeds and their potential health applications. It focuses on advances in feedstock pretreatment, extraction, characterization, and purification prior to OS use for potential health applications. Brown seaweed oligosaccharides (BSOSs) are extracted using various methods. Among these, enzymatic hydrolysis is the most preferred, with high specificity, mild reaction conditions, and low energy consumption. However, the enzyme selection and hydrolysis conditions need to be optimized for desirable yield and oligosaccharides composition. Characterization of oligosaccharides is essential to determine their structure and properties related to bioactivities and to predict their most suitable application. This is well covered in this review. Analytical techniques such as high-performance liquid chromatography (HPLC), gas chromatography (GC), and nuclear magnetic resonance (NMR) spectroscopy are commonly applied to analyze oligosaccharides. BSOSs exhibit a range of biological properties, mainly antimicrobial, anti-inflammatory, and prebiotic properties among others. Importantly, BSOSs have been linked to possible health advantages, including metabolic syndrome management. Metabolic syndrome is a cluster of conditions, such as obesity, hypertension, and dyslipidemia, which increase the risk of cardiovascular disease and type 2 diabetes. Furthermore, oligosaccharides have potential applications in the food and pharmaceutical industries. Future research should focus on improving industrial-scale oligosaccharide extraction and purification, as well as researching their potential utility in the treatment of various health disorders.[Figure: see text].

Brown algae exhibit a great diversity to offer a wide range of OSs bioactivities.Non-enzymatic extraction yields 30-58% OSs more than enzymatic routes.Enzymatically derived OSs exhibit better bioactivity than non-enzymatic OSs.Nanofiltration/activated carbon can solve bottlenecks in large-scale purification.OSs health applications are proven at in vitro stage, clinical studies yet to be done.

Advances in oligosaccharides production from algal sources and potential applications.

In recent years, algal-derived glycans and oligosaccharides have become increasingly important in health applications due to higher bioactivities than plant-derived oligosaccharides. The marine organisms have complex, and highly branched glycans and more reactive groups to elicit greater bioactivities. However, complex and large molecules have limited use in broad commercial applications due to dissolution limitations. In comparison to these, oligosaccharides show better solubility and retain their bioactivities, hence, offering better applications opportunity. Accordingly, efforts are being made to develop a cost-effective method for enzymatic extraction of oligosaccharides from algal polysaccharides and algal biomass. Yet detailed structural characterization of algal-derived glycans is required to produce and characterize the potential biomolecules for improved bioactivity and commercial applications. Some macroalgae and microalgae are being evaluated as in vivo biofactories for efficient clinical trials, which could be very helpful in understanding the therapeutic responses. This review discusses the recent advancements in the production of oligosaccharides from microalgae. It also discusses the bottlenecks of the oligosaccharides research, technological limitations, and probable solutions to these problems. Furthermore, it presents the emerging bioactivities of algal oligosaccharides and their promising potential for possible biotherapeutic application.