Abstract: Arachidonate 5-lipoxygenase (ALOX5) is a key enzyme implicated in several inflammatory disorders, including asthma and allergic rhinitis. Despite its therapeutic importance, only one compound is currently approved as an ALOX5 inhibitor in the United States, highlighting the urgent need for new drug candidates. Progress in this area is often hindered by conventional bioassays, which can be labor-intensive, costly, and unsuitable for complex mixtures. To overcome these challenges, we developed a simple thin-layer chromatography (TLC) bioautographic assay for the rapid detection of ALOX5 inhibitors in natural extracts, a rich source of pharmacologically active compounds. The method exploits the oxidative coupling of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with 3-(dimethylamino)benzoic acid (DMAB) during the ALOX5-catalyzed conversion of arachidonic acid, producing a colored indamine dye. Experimental parameters influencing chromogenic reaction were investigated and optimized to minimize reagent consumption while ensuring accuracy and sensitivity of the method. The assay was then applied to a panel of natural products and to crude mushroom extracts, enabling the rapid identification of several active compounds within complex extracts, including the dual COX2/ALOX5 inhibitor 3α-acetylpolyporenic acid A. Easy to implement, cost-efficient, and well suited for screening and bioguided fractionation, this TLC bioassay provides a powerful tool to accelerate the discovery of novel anti-inflammatory compounds.

Abstract: Hypochlorous acid (HClO) is widely used as a low-cost and effective disinfectant; however, its instability under heat and light necessitates simple and reliable monitoring methods. Herein, we report a morphology-evolving thin-film colorimetric sensor that enables intuitive visual detection of HClO through simultaneous color and pattern transitions. The sensor integrates two polymer films with distinct charge-state response behaviors, patterned into X-shaped and circular geometries on a single substrate. Upon exposure to HClO, chlorine-induced modification of amide and amine groups alters the surface charge states, thereby switching the adsorption preference for anionic and cationic dyes. This mechanism results in a pronounced transformation from a blue X-shaped motif to a red circular pattern, enabling direct visual discrimination of HClO concentrations. Quantitative analysis of RGB values and diffuse-reflectance UV–vis spectra confirmed semi-quantitative detection in the sub-millimolar to low millimolar range. The sensor further demonstrated practical applicability by tracking photodecomposition of a commercial disinfectant. This work demonstrates pattern-coupled colorimetric sensing as a straightforward, user-friendly approach for HClO monitoring.

Abstract: This study investigates the decomposition kinetics and microplastic residue formation of the polymer-coated controlled-release fertilizers (CRFs) LN40 and Eco-LN40 under simulated photodegradation conditions. Eco-LN40, containing TiO₂ as a photocatalyst, achieved complete decomposition (100 ± 2%) after 60 days of xenon-arc irradiation (p <0.05), whereas LN40 achieved only 14%–31% decomposition. Analytical characterization using TED-GC/MS, FTIR, and Raman spectroscopy confirmed that polyethylene (PE) signals completely disappeared in Eco-LN40 but persisted in LN40, indicating that microplastics did not form and that there was total oxidation into CO₂ and H₂O. SEM–EDS revealed Ti enrichment and surface fragmentation consistent with photoinduced radical oxidation. This study provides qualitative and mechanistic evidence that TiO-catalyzed photodegradation can eliminate polymer residues, mitigate the risk of microplastic contamination in agricultural soils, and support carbon-neutral fertilizer technologies.

Abstract: A cornerstone in transferring a classical Liquid Chromatography (LC) with UltraViolet/Visible (UV/Vis) detector into a greener and, beyond, towards a sustainable analytical method should consider the safety and health of the used organic solvent in the method. Toxic organic solvent portions used in the mobile phase can be replaced by an eco-friendly green solvent that is ideally bio-based and biodegradable to increase the greenness index of the method. However, the implementation of a new organic solvent for High Performance Liquid Chromatography (HPLC-UV/Vis) and/or UltraHigh Performance Liquid Chromatography (UHPLC-UV/Vis) requires not only a simple consideration of its environmental and health impact, cost-effectiveness, user-friendliness, and impact on the analytical performance of the method but rather a systematic evaluation of its chromatographic suitability. Existing greenness, blueness, and redness metrics expressing whiteness for evaluating the sustainability of liquid chromatographic methods after solvent replacement overlook the chromatographic suitability of the selected green solvent, potentially leading to suboptimal solvent replacement and an incomplete view of its capabilities. In this work, the authors present a Universal Suitability and Sustainability Index (USSI), a sixteen-parameter scoring system that quantifies four main factors for complete evaluation of a new solvent for implementation in liquid chromatography. This index is even beyond the white analytical chemistry principle. The four main factors are chromatographic suitability, greenness, blueness, and redness. Three of these factors, namely greenness, blueness, and redness, are based on available tools and metrics to evaluate the environmental and health, impact on the practicability, and the analytical performance of the method. The fourth factor is added as an important criterion to judge the suitability of the solvent to liquid chromatographic analysis and to give an overview about its analytical chromatography-oriented applicability. The new index has been used to evaluate traditional solvent-based liquid chromatographic methods as well as those based on alternative emerging green solvents and compare the factors together to give a universal overview that aids users to drive a rapid imprison on the weakness and strength aspects and makes it easier to judge the selection of the solvent and the evaluation of the overall method sustainability.

Abstract: A simple, rapid, and cost-effective method for the determination of BaP in edible oil was developed and validated. Nickel oxide deposited silica (SiO2@NiO) prepared by depositing nickel oxide onto silica using liquid phase deposition method was employed as solid-phase extraction (SPE) adsorbent for the extraction of benzo[a]pyrene (BaP) in edible oil followed by high performance liquid chromatography-diode array detector (HPLC-DAD) analysis. The edible oil was diluted with n-hexane and then directly loaded to SiO2@NiO for SPE. The n-hexane was also used to clean the fat-soluble interference in the edible oil, while BaP was selectively captured due to the electron donor-acceptor interaction with SiO2@NiO. The extraction conditions such as amount of sorbent, volume of washing solvent, type and volume of desorption solvent were optimized. The method demonstrated good linearity over the range of 6-1875 ng/g with the limit of detection of 1.3 ng/g, the spiked recoveries in the range of 97.4-105.1 %, and the relative standard deviation (RSD) less than 3.0 %. The method was applied for the analysis of BaP in 12 actual oil samples and the results showed that unrefined oil and high-temperature frying oil were at risk of BaP exceeding the acceptable level.

Abstract: Objectives: Using high-performance liquid chromatography (HPLC) we developed and validated an in vitro assay for the quantitative determination of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) activity, supplementing limited current methodologies to assess the efficacy of BACE1 inhibitor compounds. A hexa-histidine tagged peptide substrate of BACE1 was used as the analyte for the determination of in vitro BACE1 activity; it was validated according to ICH guidelines. Methods: The HPLC analysis was performed on the Agilent 1290 Series Infinity II UHPLC System equipped with a Phenomenex Kinetex EVO C18 (100 × 3 mm) 5 µm column. The method was developed using a gradient program comprising of 10 % aqueous acetonitrile (0.02 M TFA) to 30% aqueous acetonitrile (0.02 M TFA) for 5 minutes at a flow rate of 0.6 ml/min. Results: The method showed linearity over the range of 14.92 to 72 µM with R^2=0.9997. The accuracy of the method in terms of mean recovery ranged between 96.62 to 98.38 %. The %RSD for intra- and inter-day precision were less than 5 %. Two commercial inhibitors, AZD3839 and OM99-2, were used to evaluate the performance of the method at their respective IC50, resulting in inhibition of 53.46 and 50.74 % respectively. The described method addresses the void for a practical and cheap alternative to quantitatively determine the activity of BACE1 compared to current commercially available detection assays. Conclusions: We have successfully developed a HPLC method to measure the inhibitory function of two commercial inhibitors of BACE1, indicating suitability of the method for the identification and characterisation of novel BACE1 inhibitors.

Abstract: Because of their special optical and electrochemical characteristics, superior biocompatibility, adjustable surface chemistry, and inexpensive, scalable synthesis, carbon dots (CDs), including carbon quantum dots and graphene quantum dots, have become powerful and adaptable nanomaterials for advanced pharmaceutical analysis and other toxicants. The sensitive and selective detection of active pharmaceutical substances, degradation products, contaminants, biomarkers, and therapeutic medication levels in complex matrices has shown great promise in recent years with carbon dot-based nanobiosensors. The development of various sensing platforms, such as electrochemical, optical, and dual-mode biosensors, as well as integration into microfluidic, paper-based, and wearable point-of-care devices, are made possible by their intrinsic fluorescence, effective electron transfer capacity, and ease of functionalization. With an emphasis on sensing mechanisms, biorecognition techniques, and analytical performance, this study critically reviews current developments in carbon dot-based nanobiosensors for pharmaceutical analysis. It includes a thorough discussion of important applications in drug development, stability research, therapeutic drug monitoring, and drug quality control. Along with new developments like green synthesis, AI-assisted signal processing, and smart sensing platforms, current issues with reproducibility, standardization, biocompatibility, and regulatory validation are highlighted. Lastly, prospects for the industrial application and clinical translation of carbon dot-based nanobiosensors are discussed.

Abstract: Urban water security in the Global South is increasingly governed by the coupled degradation of aging infrastructure and the persistence of complex chemical stressors. This study presents a longitudinal, systems-level assessment (2020–2024) of the Harare metropolitan water continuum, conceptualizing the system as an active evolutionary reactor rather than a passive conveyance network. A three-stage analytical framework was applied, beginning with Stage I (2020) detection of the persistent antibiotics sulfamethoxazole and trimethoprim at the Lake Chivero water–sediment interface using a solid-phase extraction method developed by our group. This baseline was integrated with a Stage II (2021) spatial assessment of physicochemical instability across treat-ment and distribution infrastructure, followed by Stage III (2024) validation of pharmaceutical and agrochemical persistence using an optimized liquid–liquid extraction approach. Sulfamethoxazole and trimethoprim were identified using high-performance liquid chromatography (HPLC), while atrazine was confirmed by gas chromatography–mass spectrometry (GC–MS). These qualitative analyses demonstrated incomplete interruption of antibiotic transfer from wastewater effluent into Lake Chivero, which functions as a primary environmental reservoir for chemical and biological selection. The additional identification of atrazine established the presence of a non-antibiotic co-selective stressor within the same matrices. Distribution-system instability, marked by collapse of the free residual chlorine barrier under elevated ammonia loading, coincided with microbial recovery at distal consumer endpoints. Antimicrobial susceptibility testing of source-interface isolates revealed reduced susceptibility to the detected antibiotics, linking chronic sub-therapeutic exposure to environmentally relevant resistance phenotypes. Viewed through a One Health lens, these findings underscore the need for integrated water management strategies that extend beyond centralized treatment to encompass wastewater control, source-water protection, and distribution-system stability.

Abstract: Wearable electrochemical biosensors have catalyzed a shift toward personalized medicine and are gaining commercial traction, largely because they can deliver high specificity and sensitivity using operationally simple, rapid, portable, low-cost, and compact formats that support continuous, real-time analysis with user-friendly workflows. Concurrent advances in multitechnology biosensing architectures and scalable manufacturing have accelerated the development of lab-on-a-chip systems and wearable devices capable of interrogating health-relevant chemical signals at the molecular level. Nevertheless, the functional ceiling of many wearable platforms remains constrained by insufficiently selective recognition of target biomolecules, a deficiency that can propagate cross-reactivity, compromise analytical fidelity in complex biofluids, and ultimately limit clinical interpretability and adoption. Addressing this limitation requires more rigorous integration of molecular recognition strategies with electrode design, including interface engineering that preserves bioreceptor activity while suppressing nonspecific interactions under dynamic on-body conditions. In this context, progress in nanomaterials has enabled the coupling of nanomaterial-enabled electrochemical transduction with wearable electrodes to improve signal generation and interfacial control. This review introduces key electrochemical biointerfaces and core electroanalytical modalities (voltage, amperometry, and impedance techniques), emphasizing their translation to wearable formats for biofluid analysis. It further provides a critical analysis of integrated multitechnology wearable biosensor platforms, highlighting design considerations and performance trade-offs that inform next-generation systems for biomolecular detection.

Abstract: Early detection of cancer biomarkers in blood is critical for improving patient outcomes; however, conventional immunoassays often rely on complex instrumentation and are not well suited for point-of-care testing or multiplexed analysis. Herein, we present a dual-mode colorimetric–surface-enhanced Raman scattering (SERS) lateral flow immunoassay (LFIA) platform for multiplexed detection of cancer biomarkers, employing elongated rod-shaped silver nanoshells (ERNSs) as SERS nanotags. The ERNS features a rough Ag shell with internally incorporated Raman labeling compounds (RLCs), enabling plasmonic extinction for visual readout and strong SERS signals for quantitative analysis while preserving the external metal surfaces for efficient antibody conjugation. Leveraging these advantages, a multiplex LFIA capable of simultaneously detecting prostate-specific antigen (PSA) and carbohydrate antigen 19-9 (CA19-9) on a single strip was successfully demonstrated. Visual inspection enabled rapid discrimination of samples at or near clinically relevant cut-off levels, while Raman analysis achieved limits of detection of 8.0 × 10-3 ng/mL for PSA and 5.4 × 10-2 U/mL for CA19-9, corresponding to approximately 500-fold and 685-fold lower concentrations than their respective clinical thresholds. This ERNS-based colorimetric–SERS LFIA integrates rapid screening and highly sensitive quantification within a single platform and offers a versatile nanoprobe design strategy for multiplex biomarker detection and liquid biopsy–based point-of-care diagnostics.

Abstract: A flexible paper base SERS substrate with hydrophobic surface was fabricated through a simple route. The Ag nanoparticle was modified on filter paper through in situ growth method. After optimizing the condition during the growth and surface modification process, the hydrophobic filter paper-Ag was prepared via soaking in 10-8 g/ml of 1-Dodecanethiol with 12 h growth time. The flexible SERS substrate exhibit excellent hydrophobic properties, the contact angle of water could achieve 130.2 °. When the solution of analyte was dropped onto the SERS substrate, the diffusion effect was limited. After evaporation, the target analyte was concentrated within a fixed area. The hydrophobic SERS substrate could simultaneously improve the SERS signal and fluorescence of the analyte. The paper base SERS substrate with hydrophobic surface was used for detecting thiram from edible oil, and the sensitivity was down to 10-7 M. We proposed a flexible, economical and green hydrophobic SERS substrate for the detection of harmful ingredient from hydrophobic phase.

Abstract:

Polyphenols are a structurally diverse group of plant secondary metabolites widely recognized for their antioxidant, anti-inflammatory, antimicrobial, and chemoprotective properties, which have stimulated their extensive use in food, pharmaceutical, nutraceutical, and cosmetic products. However, their chemical heterogeneity, wide polarity range, and strong interactions with plant matrices pose major challenges for efficient extraction, separation, and reliable analytical characterization. This review provides a critical overview of contemporary strategies for the extraction, separation, and identification of polyphenols from plant-derived matrices. Conventional extraction methods, including maceration, Soxhlet extraction, and percolation, are discussed alongside modern green technologies such as ultrasound-assisted extraction, microwave-assisted extraction, pressurized liquid extraction, and supercritical fluid extraction. Particular emphasis is placed on environmentally friendly solvents, including ethanol, natural deep eutectic solvents, and ionic liquids, as sustainable alternatives that improve extraction efficiency while reducing environmental impact. The review further highlights chromatographic separation approaches—partition, adsorption, ion-exchange, size-exclusion, and affinity chromatography—and underlines the importance of hyphenated analytical platforms (LC–MS, LC–MS/MS, and LC–NMR) for comprehensive polyphenol profiling. Key analytical challenges, including matrix effects, compound instability, and limited availability of reference standards, are addressed, together with perspectives on industrial implementation, quality control, and standardization.

Abstract: Forensic ethanol gas standards are used for, among other, the calibration and metrological verification of evidential breath analysers as described in OIML-R126. A correction for the amount fraction ethanol in forensic gas standards due to cylinder wall adsorption is described. The correction was developed for both the national primary measurement standards as well as for derived primary reference materials. A novel method based on the well-known decanting principle was developed and assessed using two suites of gas mixtures with ethanol amount fractions between 50 μmol mol⁻¹ to 1000 μmol mol⁻¹ in nitrogen. From the results, it is inferred that the initial adsorption loss is a function of the amount fraction and an interpolation formula was developed accordingly. To account for differences in adsorption between cylinders, a mixed effects model was used to describe the adsorption loss data with an excess standard deviation to account for between-cylinder effects.

Abstract: Growing global populations and the rapid increase in older adults are driving healthcare costs upward. In response, the healthcare system is shifting toward models that allow for continuous monitoring of individuals without requiring hospital ad-mission. Advances in sensing technologies, embedded systems, wireless communica-tion, nanotechnology, and device miniaturization have made it possible to develop smart systems that continuously track human activity. Wearable sensors can monitor physiological indicators and other symptoms, helping to detect unusual or unexpected events. This enables timely assistance when it is needed most. This paper outlines these challenges and reviews recent developments in wearable sensor–based human activity monitoring systems. The focus is on health monitoring applications, including relevant biomarkers, wearable and implantable sensors, estab-lished sensor technologies currently used in healthcare, and the future prospects and challenges involved in researching, developing, and applying these sensors to support widespread use in human health monitoring.

Abstract:

Pesticide contamination poses significant threats to both humans and the environment, with residues frequently detected in surface waters worldwide. This study compares the effectiveness of passive samplers (POCIS and Chemcatcher), and grab sampling coupled with Stir Bar Sorptive Extraction (SBSE) and Solid Phase Extraction (SPE) for monitoring pesticides in surface waters. The comparative study was conducted at three sites in Victoria, Australia, representing different land uses. A total of 230 pesticides were screened, with 79 different pesticides detected overall. SBSE extracted the highest number of pesticides from grab samples, followed by SPE and passive samplers. The study highlights the complementarity of different sampling and extraction techniques in detecting a wide range of pesticides. The study also explores the suitability of these techniques for citizen science applications, emphasizing the importance of selecting appropriate methods based on specific research objectives and available resources. The findings underscore the need for a tiered approach, combining passive samplers for initial screening and grab sampling for quantitative analysis, to develop a robust monitoring strategy for protecting water quality.

Abstract: Background: Cleaning validation is a critical component of pharmaceutical manufacturing quality assurance, ensuring the prevention of cross-contamination between production batches. Two predominant analytical techniques, High-Performance Liquid Chromatography (HPLC) and Total Organic Carbon (TOC) analysis, are widely employed for residue detection, yet the optimal selection between these methodologies remains a subject of ongoing debate within the industry. Objective: This review critically evaluates the comparative advantages, limitations, and application contexts of HPLC and TOC analysis in pharmaceutical cleaning validation programs, providing evidence-based guidance for method selection. Methods: A comprehensive literature review was conducted examining peer-reviewed publications, regulatory guidance documents, and industry case studies from 2010 to 2025. Selection criteria included studies comparing analytical performance, regulatory compliance, and practical implementation considerations. Results: HPLC demonstrates superior specificity for active pharmaceutical ingredient (API) quantification with detection limits typically ranging from 0.1–10 µg/mL, while TOC analysis offers advantages in non-specific organic contamination detection with broader applicability and faster analysis times (typically 3–8 minutes versus 15–60 minutes for HPLC). Regulatory guidance from the FDA and EMA supports both methodologies when appropriately validated, with the selection dependent on the specific cleaning validation objectives. Conclusions: Neither technique is universally superior; rather, the optimal choice depends on the validation objective, equipment characteristics, product portfolio complexity, and regulatory requirements. A risk-based approach combining both methodologies may provide the most comprehensive cleaning validation strategy for multi-product facilities.

Abstract: An optical fiber chemical sensor using a molecularly imprinted chitosan membrane coated on the surface of a bent optical fiber probe was developed for selectively analyzing 4-nitrophenol (4-NP) in water samples. When the sensor probe was exposed to a water sample, the chitosan MIP membrane extracts/concentrates 4-NP from water sample into the membrane. The 4-NP extracted into the membrane was detected by passing a light beam through the optical fiber, and the interaction of 4-NP in the membrane with evanescent wave of light guided through the optical fiber was detected as a sensing signal. This sensor detects the intrinsic optical absorption signal of 4-NP itself as a sensing signal. No chemical reagent was needed in analyzing this compound in a sample. The sensor is reversible, can be used for continuous monitoring of 4-NP in a sample, and has quick response with a response time of 5 min. The sensor has high sensitivity and selectivity because the MIP membrane selectively concentrates 4-NP by 1.4*104 times into the membrane from a sample solution, but blocks out interference species, including its isomers and derivatives, from entering the membrane. The sensor achieved a detection limit of 2.5 ng/mL (0.018 µM), which is lower than most reported analytical techniques for analyzing this compound in water sample. This sensor can discriminate 4-NP from its isomers and derivatives, such as 2-NP, 3-NP, 2-Cl-4-NP, 2,4-di-NP with a selectivity factor ranging from 104 to 1922. The sensor has been used for analyzing 4-NP in a standard addition sample. The obtained recovery rate ranged from 93% to 101%, demonstrating the application potential of this sensor in water quality analysis.

Abstract: Novel colourimetric sensors are readily devised by combining multifunctional (nano)materials with miniature optoelectronic components. The demand to detect and monitor metal ions has resulted in the invention of new colourimetric sensing schemes, especially for use at the Point-of-Need (PoN). Nonetheless, the design of fully reversible optical materials for continuous real-time ion monitoring remains a bottleneck in the practical realisation of sensors. Magnesium ion is vital to physiological and environmental processes, but monitoring can be challenging, particularly in the presence of Ca2+ as a cross-sensitive interferent in real samples. In this work, a chromophore molecule Hyphan I (1-(2-hydroxy-5-ß-hydroxyethylsulfonyl-phenyl-azo)-2-naphthol) has been grafted onto a cellulose matrix with a simple one-pot vinylsulfonyl process, to form a transparent, biocompatible and highly flexible thin-film colourimetric magnesium ion sensing material (Cellulose Film with Hyphan - CFH). The CFH film has a pH response time of < 60s over the pH range 4 to 9, with a pKa = 5.8. The LOD and LOQ for Mg2+ at pH 8 are 0.089 mM and 0.318 mM, respectively, with an RSD = 0.93%. The CFH film exhibits negligible interference from alkaline and alkaline earth metals, but irreversibly binds certain transition metals (Fe3+, Cu2+ and Zn2+). The CFH material has a fast and fully reversible colourimetric response to pH and Mg2+ over physiologically relevant ranges without interference by Ca2+, demonstrating good potential for integration into microfluidic systems and wearable sensors for biofluid monitoring.

Abstract: A nanobioarray (NBA) chip has been developed with the goal of having a high throughput system that analyze proteins of low sample volumes against multiple probes in a short time. A combination of horizontal and vertical channels are produced to create an antigen array on the surface of the NBA chip in one dimension that is probed by flowing protein samples (e.g. antibodies) from biological fluids in the orthogonal dimension. To improve sensitivity, we have tested the NBA chip by immobilizing streptavidin and then biotinylated peptide to detect the presence of a mouse monoclonal antibody (MAb) that is specific for the peptide. Bound antibody is detected by an AlexaFluor 647 labeled goat (anti-mouse IgG) polyclonal antibody. Using this NBA chip, we have successfully detected antibodies in samples in 500 nL containing 50 pM of MAb (or 25 attomoles), and this demonstrates a detection limit below that of a comparable ELISA, utilizing a shorter reaction time. Such a system is intended for assays of protein mixtures in biofluids, even for proteomic studies.

Abstract:

In this study, three point mutations of EGFR relevant to lung cancer therapy are detected. Mutated EGFR is the target of a therapy for non-small cell lung cancer (NSCLC) using tyrosine kinase inhibitors (TKIs) as treatment drugs. Background/Objectives: Point mutations in exon 21 (L858R and L861Q) of the EGFR gene are TKI-sensitive; however, mutations in exon 20 (T790M) are TKI-resistant. Therefore, a fast detection method that classifies a NSCLC patient to be drug sensitive or drug resistant is highly clinically relevant. Methods: Probes were designed to detect three point mutations in genomic samples based on DNA hybridization on a solid surface. A method has been developed to detect single nucleotide polymorphism (SNP) for these mutation detections in the 16-channel nanobioarray chip. The wash by gold-nanoparticles (AuNP) was used to assist the differentiation detection Results: The gold nanoparticle-assisted wash method has enhanced differentiation between WT and mutated sequences relevant to the EGFR sensitivity to tyrosine kinase inhibitors. Conclusions: The WT and mutated sequences (T790M, L858R and L861Q) in genomic samples were successfully differentiated from each other.