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This paper outlines the design and fabrication of a portable optomechatronic system based on the theta-2theta configuration, which explores various optical characterization techniques for transparent materials and dielectric thin films. These techniques include Brewster angle and Abelès-Brewster angle measurements, critical angle measurements, and the surface plasmon resonance technique. The system consists of a mechanical assembly of rotating stages, a semiconductor laser, a photodiode connected to a data acquisition card, and a user interface for controlling the stepper motor rotation stages. Utilizing a BK7 substrate, the motorized stage achieved a resolution of 0.010. The Brewster angle measured was 56.550, with a refractive index (n) of 1.5137. The relative error obtained was Δn/n = 3.82 × 10−4, with a sensitivity of 164.27 RIU/degree and an accuracy of 0.37/degree. Furthermore, the discrepancies between theoretical and experimental refractive indices for different prisms at 639 nm ranged from ±7 × 10−4 to ±73 × 10−4. After testing various samples, the system demonstrated its capability to perform fast, precise, and non-invasive measurements. Its portability allows for use in diverse environments and applications.

This study examines the significant impact of bacterial, algal, and fungal toxins on foodborne illnesses, and stresses the importance of advanced detection techniques, such as high-performance liquid chromatography (HPLC)-based methodologies. It emphasizes the urgent need for further advancements in these techniques to ensure food safety, as they offer significant benefits, including low detection limits and the ability to be combined with other techniques to detect a wide range of toxins. In this regard, HPLC has emerged as a versatile and sensitive analytical technique for this purpose. Various HPLC methods, often enhanced with detectors such as ultraviolet (UV), fluorescence (FD), and mass spectrometry (MS), have been developed to identify and quantify microbial toxins in a wide variety of food samples. Recent advancements include HPLC-FD methods that utilize the natural fluorescence of certain aflatoxins, improving detection sensitivity. HPLC-MS/MS and UHPLC-MS/MS techniques offer high selectivity and sensitivity, making them suitable for detecting a wide range of toxins in trace quantities. The adaptability of HPLC, combined with innovative detection technologies and sample preparation methods, holds significant potential for enhancing food safety monitoring and reducing the global burden of foodborne diseases.

Glycine, a simple amino acid, is not only essential due to its potential insufficiency in vivo, but also has significant metabolic functions. It serves as a crucial building block for proteins. At the same time, as a bioactive molecule, it regulates gene expression for cytoprotection, protein configuration and activity, and other critical biological processes, including glutathione synthesis. The intriguing, beneficial effects of glycine in medical applications have piqued the research community’s interest in recent decades. This work delves into the compelling discoveries about the pivotal role of glycine in cardiovascular health and its intricate mechanisms of action for alleviating several medical conditions. Glycine’s broad spectrum of impact spans numerous diseases, encompassing not only acute myocardial infarction, aortic dissection, and cardiac hypertrophy, but also transplant rejections of aortic allografts, insulin resistance, and endothelial dysfunction, thereby providing a comprehensive understanding of its medical applications.

Plastic pollution, particularly from microplastics (MPs) and nanoplastics (NPs), has become a critical environmental and health concern due to their widespread distribution, persistence, and potential toxicity. MPs and NPs originate from primary sources, such as cosmetic microspheres or synthetic fibers, and secondary fragmentation of larger plastics through environmental degradation. These particles, typically less than 5 mm, are found globally, from deep seabeds to human tissues, and are known to adsorb and release harmful pollutants, exacerbating ecological and health risks. Effective detection and quantification of MPs and NPs are essential for understanding and mitigating their impacts. Current analytical methods include physical and chemical techniques. Physical methods, such as optical and electron microscopy, provide morphological details but often lack specificity and are time-intensive. Chemical analyses, such as Fourier transform infrared (FTIR) and Raman spectroscopy, offer molecular specificity but face challenges with smaller particle sizes and complex matrices. Thermal analytical methods, including pyrolysis gas chromatography–mass spectrometry (Py-GC-MS), provide compositional insights but are destructive and limited in morphological analysis. Emerging (bio)sensing technologies show promise in addressing these challenges. Electrochemical biosensors offer cost-effective, portable, and sensitive platforms, leveraging principles such as voltammetry and impedance to detect MPs and their adsorbed pollutants. Plasmonic techniques, including surface plasmon resonance (SPR) and surface-enhanced Raman spectroscopy (SERS), provide high sensitivity and specificity through nanostructure-enhanced detection. Fluorescent biosensors utilizing microbial or enzymatic elements enable the real-time monitoring of plastic degradation products, such as terephthalic acid from polyethylene terephthalate (PET). Advancements in these innovative approaches pave the way for more accurate, scalable, and environmentally compatible detection solutions, contributing to improved monitoring and remediation strategies. This review highlights the potential of biosensors as advanced analytical methods, including a section on prospects that address the challenges that could lead to significant advancements in environmental monitoring, highlighting the necessity of testing the new sensing developments under real conditions (composition/matrix of the samples), which are often overlooked, as well as the study of peptides as a novel recognition element in microplastic sensing.

Methylene blue is a cationic organic dye commonly found in wastewater, groundwater, and surface water due to industrial discharge into the environment. This emerging pollutant is notably persistent and can pose risks to both human health and the environment. In this study, we developed a Surface Plasmon Resonance Biosensor employing a BK7 prism coated with 3 nm chromium and 50 nm of gold in the Kretschmann configuration, specifically for the detection of methylene blue. For the first time, laccases immobilized on a gold surface were utilized as bio-receptors for this organic dye. The enzyme was immobilized using carbodiimide bonds with EDC/NHS crosslinkers, allowing for the analysis of samples with minimal preparation. The method demonstrated validation with a limit of detection (LOD) of 4.61 mg L−1 and a limit of quantification (LOQ) of 15.37 mg L−1, a working range of 0–100 mg L−1, and an R2 value of 0.9614 during real-time analysis. A rainwater sample spiked with methylene blue yielded a recovery rate of 122.46 ± 4.41%. The biosensor maintained a stable signal over 17 cycles and remained effective for 30 days at room temperature.

Aquaculture is an expanding economic sector that nourishes the world’s growing population due to its nutritional significance over the years as a source of high-quality proteins. However, it has faced severe challenges due to significant cases of environmental pollution, pathogen outbreaks, and the lack of traceability that guarantees the quality assurance of its products. Such context has prompted many researchers to work on the development of novel, affordable, and reliable technologies, many based on nanophotonic sensing methodologies. These emerging technologies, such as surface plasmon resonance (SPR), localised SPR (LSPR), and fibre-optic SPR (FO-SPR) systems, overcome many of the drawbacks of conventional analytical tools in terms of portability, reagent and solvent use, and the simplicity of sample pre-treatments, which would benefit a more sustainable and profitable aquaculture. To highlight the current progress made in these technologies that would allow them to be transferred for implementation in the field, along with the lag with respect to the most cutting-edge plasmonic sensing, this review provides a variety of information on recent advances in these emerging methodologies that can be used to comprehensively monitor the various operations involving the different commercial stages of farmed aquaculture. For example, to detect environmental hazards, track fish health through biochemical indicators, and monitor disease and biosecurity of fish meat products. Furthermore, it highlights the critical issues associated with these technologies, how to integrate them into farming facilities, and the challenges and prospects of developing plasmonic-based sensors for aquaculture.

Despite the increasing number of reports that relate antimicrobial chlorophene (CP) with health and environmental effects, few studies have addressed biosensing technologies to detect this threat. This work proposed an electrochemical approach for the detection of CP using laccase enzymes as an alternative recognition element immobilized onto thin-film gold electrodes. The electrochemical parameters of the detection method, under controlled conditions, resulted in a limit of detection (0.14 ± 0.06 mg L−1) and quantification (0.48 ± 0.04 mg L−1) that agreed with concentrations of CP that already had been measured in natural water samples. Nevertheless, during the analysis of natural river water samples, the provided method suffered a drawback due to matrix effects reflected in the obtained recovery percentage, the value of which was 62.0 ± 2.4% compared to the 101.3 ± 3.5% obtained by the HPLC reference method. These detrimental effects were mainly attributed to organic matter, SO4-2, and Cl- present in river samples.

Chlorophene is an important antimicrobial agent present in disinfectant products which has been related to health and environmental effects, and its detection has been limited to chromatographic techniques. Thus, there is a lack of research that attempts to develop new analytical tools, such as biosensors, that address the detection of this emerging pollutant. Therefore, a new biosensor for the direct detection of chlorophene in real water is presented, based on surface plasmon resonance (SPR) and using a laccase enzyme as a recognition element. The biosensor chip was obtained by covalent immobilization of the laccase on a gold-coated surface through carbodiimide esters. The analytical parameters accomplished resulted in a limit of detection and quantification of 0.33 mg/L and 1.10 mg/L, respectively, fulfilling the concentrations that have already been detected in environmental samples. During the natural river’s measurements, no significant matrix effects were observed, obtaining a recovery percentage of 109.21% ± 7.08, which suggested that the method was suitable for the fast and straightforward analysis of this contaminant. Finally, the SPR measurements were validated with an HPLC method, which demonstrated no significant difference in terms of precision and accuracy, leading to the conclusion that the biosensor reflects its potential as an alternative analytical tool for the monitoring of chlorophene in aquatic environments.