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Chemosensors
Volume 13
Issue 7
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Chemosensors, Volume 13, Issue 7 (July 2025) – 48 articles

Cover Story (view full-size image): MicroRNAs (miRNAs) are non-coding RNA molecules that play crucial roles in gene regulation. Aberrant miRNA expressions have been implicated in numerous pathological conditions. In oncology, miRNA profiles have been correlated with tumor initiation, progression, and metastasis across various cancer types. Traditional characterization of miRNAs has been utilized for early disease detection, yet their use in clinical settings remains challenging. To address these limitations, electrochemical biosensors have been designed. Importantly, the integration of nanomaterials and signal amplification strategies has enhanced the performance of these biosensors. This review focuses on redox-based methods, various hybridization modes, and the implementation of nanomaterials and amplification strategies, highlighting their potential use in clinical settings. View this paper
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35 pages, 2590 KB  
Review
Advanced Chemometric Techniques for Environmental Pollution Monitoring and Assessment: A Review
by Shaikh Manirul Haque, Yunusa Umar and Abuzar Kabir
Chemosensors 2025, 13(7), 268; https://doi.org/10.3390/chemosensors13070268 - 21 Jul 2025
Viewed by 608
Abstract
Chemometrics has emerged as a powerful approach for deciphering complex environmental systems, enabling the identification of pollution sources through the integration of faunal community structures with physicochemical parameters and in situ analytical data. Leveraging advanced technologies—including satellite imaging, drone surveillance, sensor networks, and [...] Read more.
Chemometrics has emerged as a powerful approach for deciphering complex environmental systems, enabling the identification of pollution sources through the integration of faunal community structures with physicochemical parameters and in situ analytical data. Leveraging advanced technologies—including satellite imaging, drone surveillance, sensor networks, and Internet of Things platforms—chemometric methods facilitate real-time and longitudinal monitoring of both pristine and anthropogenically influenced ecosystems. This review provides a critical and comprehensive overview of the foundational principles underpinning chemometric applications in environmental science. Emphasis is placed on identifying pollution sources, their ecological distribution, and potential impacts on human health. Furthermore, the study highlights the role of chemometrics in interpreting multidimensional datasets, thereby enhancing the accuracy and efficiency of modern environmental monitoring systems across diverse geographic and industrial contexts. A comparative analysis of analytical techniques, target analytes, application domains, and the strengths and limitations of selected in situ and remote sensing-based chemometric approaches is also presented. Full article
(This article belongs to the Special Issue Chemometrics Tools Used in Chemical Detection and Analysis)
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22 pages, 3657 KB  
Article
Emergency Wound Infection Monitoring and Treatment Based on Wearable Electrochemical Detection and Drug Release with Conductive Hydrogel
by Shaopeng Wang, Songsong Huang, Qian Chen, Yanjun Li, Liyang Duan, Zhi Yu, Weixia Li, Hui Luo, Shuang Li, Bin Fan and Zetao Chen
Chemosensors 2025, 13(7), 267; https://doi.org/10.3390/chemosensors13070267 - 21 Jul 2025
Viewed by 421
Abstract
At emergency sites, bacteria in the environment can cause secondary wound infections. Timely treatment of infected wounds can improve the prognosis. In this study, we designed a closed-loop system for real-time wound infection monitoring and electronically controlled drug release, enabling rapid and stable [...] Read more.
At emergency sites, bacteria in the environment can cause secondary wound infections. Timely treatment of infected wounds can improve the prognosis. In this study, we designed a closed-loop system for real-time wound infection monitoring and electronically controlled drug release, enabling rapid and stable deployment at disaster sites. Multilayer screen-printed electrodes were developed to detect uric acid (UA), pH, and temperature biomarkers. The electrode’s outermost layer was shielded by a zwitterionic conductive hydrogel (Gel) to prevent environmental interference and achieve systematic antibacterial protection through in situ reduction of silver nanoparticles (AgNPs) on its surface. For rapid and efficient drug delivery, amikacin (Ami) loaded cationic liposomes (Lipo) embedded in the zwitterionic conductive hydrogel (Gel-Lipo@Ami) were integrated as the core therapeutic carrier. This closed-loop system provides timely infection detection and enables in situ treatment during emergency rescues. Full article
(This article belongs to the Special Issue Advancements of Chemosensors and Biosensors in China—2nd Edition)
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16 pages, 2901 KB  
Article
SiO2-Al2O3-ZrO2-Ag Composite and Its Signal Enhancement Capacity on Raman Spectroscopy
by Jesús Alberto Garibay-Alvarado, Pedro Pizá-Ruiz, Armando Erasto Zaragoza-Contreras, Francisco Espinosa-Magaña and Simón Yobanny Reyes-López
Chemosensors 2025, 13(7), 266; https://doi.org/10.3390/chemosensors13070266 - 21 Jul 2025
Viewed by 389
Abstract
A ceramic–metal composite was synthesized using sol–gel and electrospinning methods to serve as a SERS substrate. The precursors used were tetraethyl orthosilicate, aluminum nitrate, and zirconium, and polyvinylpyrrolidone was added to electrospun nonwoven fibrous membranes. The membranes were sintered, decorated with silver nanoparticles. [...] Read more.
A ceramic–metal composite was synthesized using sol–gel and electrospinning methods to serve as a SERS substrate. The precursors used were tetraethyl orthosilicate, aluminum nitrate, and zirconium, and polyvinylpyrrolidone was added to electrospun nonwoven fibrous membranes. The membranes were sintered, decorated with silver nanoparticles. The enhancement substrates were made of fibers of cylindric morphology with an average diameter of approximately 190 nm, a smooth surface, and 9 nm spherical particles decorating the surface of the fibers. The enhancement capacity of the substrates was tested using pyridine, methyl orange, methylene blue, crystal violet, and Eriochrome black T at different concentrations with Raman spectroscopy to determine whether the size and complexity of the analyte has an impact on the enhancement capacity. Enhancement factors of 2.53 × 102, 3.06 × 101, 2.97 × 103, 4.66 × 103, and 1.45 × 103 times were obtained for the signal of pyridine, methyl orange, methylene blue, crystal violet, and Eriochrome black T at concentrations of 1 nM. Full article
(This article belongs to the Special Issue Spectroscopic Techniques for Chemical Analysis)
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17 pages, 2940 KB  
Article
Evaluation Methods for Stability and Analysis of Underlying Causes of Instability in Form I Atorvastatin Calcium Drug Substance
by Bo Chen, Zhilong Tang, Zhenxing Zhu, Yang Xiao, Guangyao Mei and Xingchu Gong
Chemosensors 2025, 13(7), 265; https://doi.org/10.3390/chemosensors13070265 - 21 Jul 2025
Viewed by 385
Abstract
Stability assessments of drug substances and the detection of crystalline forms are critical for ensuring drug quality and medication safety. Atorvastatin calcium drug substance samples were characterized using powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC). DSC results demonstrated a precise discrimination [...] Read more.
Stability assessments of drug substances and the detection of crystalline forms are critical for ensuring drug quality and medication safety. Atorvastatin calcium drug substance samples were characterized using powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC). DSC results demonstrated a precise discrimination of the stability of samples. An analysis of PXRD characteristic peaks and DSC melting data suggested that instability likely stems from the presence of the amorphous phase. To validate this hypothesis, blended samples containing controlled ratios of amorphous phase and crystalline Form I were prepared. Quantitative models based on PXRD, DSC, and near-infrared spectroscopy (NIRS) data were developed to predict amorphous content, and classification accuracy was evaluated. Experimental results confirmed that all three models achieved classification accuracy values exceeding 70% in the stability prediction of the two groups of samples, which included “stable” and “unstable” samples, substantiating the hypothesis. Among them, the modeling method based on NIRS data was not only non-destructive and rapid but also demonstrates a superior discrimination accuracy value reaching 100% (n = 11), showing potential for promotion and application in industrial sample detection. The quantitative correlation between amorphous content and stability was successfully established in this study, offering a novel method for a quality stability assessment of atorvastatin calcium drug substances. Full article
(This article belongs to the Special Issue Spectroscopic Techniques for Chemical Analysis)
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16 pages, 3024 KB  
Article
Rapid Microwave-Assisted Synthesis of CuSe Nanoparticles for High-Sensitivity Serotonin Biosensing in Serum
by Sankar Sekar, Ramalingam Manikandan, Shiva Kumar Arumugasamy, Saravanan Sekar, Youngmin Lee, Seung-Cheol Chang and Sejoon Lee
Chemosensors 2025, 13(7), 264; https://doi.org/10.3390/chemosensors13070264 - 21 Jul 2025
Cited by 1 | Viewed by 517
Abstract
In this study, a simple and effective approach was developed for the quantitative detection of serotonin. Hexagonal copper selenide nanostructures (CuSe) were employed to modify a disposable screen-printed carbon electrode (SPCE), and their ability to electrochemically detect serotonin in serum samples was investigated. [...] Read more.
In this study, a simple and effective approach was developed for the quantitative detection of serotonin. Hexagonal copper selenide nanostructures (CuSe) were employed to modify a disposable screen-printed carbon electrode (SPCE), and their ability to electrochemically detect serotonin in serum samples was investigated. The fabricated CuSe nanostructures exhibited an interconnected, cluster-like morphology composed of irregularly shaped particles with a distinct hexagonal crystal structure. The electrochemical results revealed that the CuSe/SPCE sensor showed better electrochemical activity and good analytical sensing performance towards serotonin detection. The sensor exhibited a linear response in the concentration range of 10 to 1000 nM, with an excellent correlation coefficient (R2 = 0.9998) and a low detection limit of 3 nM. Furthermore, the CuSe/SPCE showed better selectivity, impressive sensitivity (12.45 µM/µA cm−2), and good reproducibility toward serotonin detection, making it a promising electrochemical biosensor for serotonin detection in various real biological samples. Full article
(This article belongs to the Special Issue Electrochemical Sensing in Medical Diagnosis)
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17 pages, 3477 KB  
Article
Development of Polydopamine–Chitosan-Modified Electrochemical Immunosensor for Sensitive Detection of 7,12-Dimethylbenzo[a]anthracene in Seawater
by Huili Hao, Chengjun Qiu, Wei Qu, Yuan Zhuang, Zizi Zhao, Haozheng Liu, Wenhao Wang, Jiahua Su and Wei Tao
Chemosensors 2025, 13(7), 263; https://doi.org/10.3390/chemosensors13070263 - 20 Jul 2025
Viewed by 423
Abstract
7,12-Dimethylbenzo[a]anthracene (DMBA-7,12), a highly toxic and environmentally persistent polycyclic aromatic hydrocarbon (PAH), poses significant threats to marine biodiversity and human health due to its bioaccumulation through the food chain. Conventional chromatographic methods, while achieving comparable detection limits, are hindered by the need for [...] Read more.
7,12-Dimethylbenzo[a]anthracene (DMBA-7,12), a highly toxic and environmentally persistent polycyclic aromatic hydrocarbon (PAH), poses significant threats to marine biodiversity and human health due to its bioaccumulation through the food chain. Conventional chromatographic methods, while achieving comparable detection limits, are hindered by the need for expensive instrumentation and prolonged analysis times, rendering them unsuitable for rapid on-site monitoring of DMBA-7,12 in marine environments. Therefore, the development of novel, efficient detection techniques is imperative. In this study, we have successfully developed an electrochemical immunosensor based on a polydopamine (PDA)–chitosan (CTs) composite interface to overcome existing technical limitations. PDA provides a robust scaffold for antibody immobilization due to its strong adhesive properties, while CTs enhances signal amplification and biocompatibility. The synergistic integration of these materials combines the high efficiency of electrochemical detection with the specificity of antigen–antibody recognition, enabling precise qualitative and quantitative analysis of the target analyte through monitoring changes in the electrochemical properties at the electrode surface. By systematically optimizing key experimental parameters, including buffer pH, probe concentration, and antibody loading, we have constructed the first electrochemical immunosensor for detecting DMBA-7,12 in seawater. The sensor achieved a detection limit as low as 0.42 ng/mL. In spiked seawater samples, the recovery rates ranged from 95.53% to 99.44%, with relative standard deviations (RSDs) ≤ 4.6%, demonstrating excellent accuracy and reliability. This innovative approach offers a cost-effective and efficient solution for the in situ rapid monitoring of trace carcinogens in marine environments, potentially advancing the field of marine pollutant detection technologies. Full article
(This article belongs to the Section Electrochemical Devices and Sensors)
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32 pages, 1555 KB  
Systematic Review
A Systematic Review of the Use of Electronic Nose and Tongue Technologies for Detecting Food Contaminants
by Muhammad Zia Ul Haq, Baljit Singh, Xolile Fuku, Ahmed Barhoum and Furong Tian
Chemosensors 2025, 13(7), 262; https://doi.org/10.3390/chemosensors13070262 - 19 Jul 2025
Viewed by 618
Abstract
Sensor operations in the food industry are faced with several major challenges, including in sensitivity, selectivity, accuracy and rapid detection. Among emerging technologies, e-nose and e-tongue systems have attracted much attention from researchers. This review examines 112 studies published from 2004 to 2025, [...] Read more.
Sensor operations in the food industry are faced with several major challenges, including in sensitivity, selectivity, accuracy and rapid detection. Among emerging technologies, e-nose and e-tongue systems have attracted much attention from researchers. This review examines 112 studies published from 2004 to 2025, and examines the functionalities and performance in detecting various food product-associated analytes. The sensitivity of e-nose and e-tongue systems was analyzed using various data processing techniques. Recent research and development in leading countries (i.e., China, United Kingdom, Columbia, India, Portugal, Spain, Hungary, Ireland) was examined. The findings indicate that principal component analysis (PCA) was the most widely used technique, while more articles were published in 2021. Worldwide research contributions showed China at the forefront of e-nose studies (26.7%) and Spain leading in e-tongue research (30%). The highest sensitivity values were 99.0% for the e-nose in 2015 and 100% for the e-tongue in 2012. In specific applications, the e-nose achieved a maximum average sensitivity of 15% in apple analysis, while the e-tongue achieved a maximum average sensitivity of 40.5% in water samples. Furthermore, the review presents an in-depth discussion of key parameters, including food sample types, citation rates, analysis techniques, accuracy, and sensitivity, with graphical representations for enhanced clarity. Full article
(This article belongs to the Special Issue Applications of Electronic Nose (E-Nose) and Electronic Tongue (E-Tongue) in Food Quality)
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19 pages, 5003 KB  
Article
Coffees Brewed from Standard Capsules Help to Compare Different Aroma Fingerprinting Technologies—A Comparison of an Electronic Tongue and Electronic Noses
by Biborka Gillay, Zoltan Gillay, Zoltan Kovacs, Viktoria Eles, Tamas Toth, Haruna Gado Yakubu, Iyas Aldib and George Bazar
Chemosensors 2025, 13(7), 261; https://doi.org/10.3390/chemosensors13070261 - 18 Jul 2025
Viewed by 986
Abstract
With the development of various new types of instrumental aroma sensing technologies, there is a need for methodologies that help developers and users evaluate the performance of the different devices. This study introduces a simple method that uses standard coffee beverages, reproducible worldwide, [...] Read more.
With the development of various new types of instrumental aroma sensing technologies, there is a need for methodologies that help developers and users evaluate the performance of the different devices. This study introduces a simple method that uses standard coffee beverages, reproducible worldwide, thus allowing users to compare aroma sensing devices and technologies globally. Eight different variations of commercial coffee capsules were used to brew espresso coffees (40 mL), consisting of either Arabica coffee or a blend of Robusta and Arabica coffee, covering a wide range of sensory attributes. The AlphaMOS Astree electronic tongue (equipped with sensors based on chemically modified field-effect transistor technology) and the AlphaMOS Heracles NEO and the Volatile Scout3 electronic noses (both using separation technology based on gas chromatography) were used to describe the taste and odor profiles of the freshly brewed coffee samples and also to compare them to the various sensory characteristics declared on the original packaging, such as intensity, roasting, acidity, bitterness, and body. Linear discriminant analysis (LDA) results showed that these technologies were able to classify the samples similarly to the pattern of the coffees based on the human sensory characteristics. In general, the arrangement of the different coffee types in the LDA results—i.e., the similarities and dissimilarities in the types based on their taste or smell—was the same in the case of the Astree electronic tongue and the Heracles electronic nose, while slightly different arrangements were found for the Scout3 electronic nose. The results of the Astree electronic tongue and those of the Heracles electronic nose showed the taste and smell profiles of the decaffeinated coffees to be different from their caffeinated counterparts. The Heracles and Scout3 electronic noses provided high accuracies in classifying the samples based on their odor into the sensory classes presented on the coffee capsules’ packaging. Despite the technological differences in the investigated devices, the introduced coffee test could assess the similarities in the taste and odor profiling capacities of the aroma fingerprinting technologies. Since the coffee capsules used for the test can be purchased all over the world in the same quality, these coffees can be used as global standard samples during the comparison of different devices applying different measurement technologies. The test can be used to evaluate instrumentational and data analytical developments worldwide and to assess the potential of novel, cost-effective, accurate, and rapid solutions for quality assessments in the food and beverage industry. Full article
(This article belongs to the Special Issue Electronic Nose and Electronic Tongue for Substance Analysis)
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13 pages, 2012 KB  
Article
Electronic Nose System Based on Metal Oxide Semiconductor Sensors for the Analysis of Volatile Organic Compounds in Exhaled Breath for the Discrimination of Liver Cirrhosis Patients and Healthy Controls
by Makhtar War, Benachir Bouchikhi, Omar Zaim, Naoual Lagdali, Fatima Zohra Ajana and Nezha El Bari
Chemosensors 2025, 13(7), 260; https://doi.org/10.3390/chemosensors13070260 - 17 Jul 2025
Viewed by 496
Abstract
The early detection of liver cirrhosis (LC) is crucial due to its high morbidity and mortality in advanced stages. Reliable, non-invasive diagnostic tools are essential for timely intervention. Exhaled human breath, reflecting metabolic changes, offers significant potential for disease diagnosis. This paper focuses [...] Read more.
The early detection of liver cirrhosis (LC) is crucial due to its high morbidity and mortality in advanced stages. Reliable, non-invasive diagnostic tools are essential for timely intervention. Exhaled human breath, reflecting metabolic changes, offers significant potential for disease diagnosis. This paper focuses on the emerging role of sensor array-based volatile organic compounds (VOCs) analysis of exhaled breath, particularly using electronic nose (e-nose) technology to differentiate LC patients from healthy controls (HCs). This study included 55 participants: 27 LC patients and 28 HCs. Sensor’s measurement data were analyzed using machine learning techniques, such as principal component analysis (PCA), discriminant function analysis (DFA), and support vector machines (SVMs) that were utilized to uncover meaningful patterns and facilitate accurate classification of sensor-derived information. The diagnostic accuracy was thoroughly assessed through receiver operating characteristic (ROC) curve analysis, with specific emphasis on assessing sensitivity and specificity metrics. The e-nose effectively distinguished LC from HC, with PCA explaining 92.50% variance and SVMs achieving 100% classification accuracy. This study demonstrates the significant potential of e-nose technology towards VOCs analysis in exhaled breath, as a valuable tool for LC diagnosis. It also explores feature extraction methods and suitable algorithms for effectively distinguishing between LC patients and controls. This research provides a foundation for advancing breath-based diagnostic technologies for early detection and monitoring of liver cirrhosis. Full article
(This article belongs to the Section Analytical Methods, Instrumentation and Miniaturization)
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13 pages, 1647 KB  
Article
Electrochemical Sensing of Hg2+ Ions Using an SWNTs/Ag@ZnBDC Composite with Ultra-Low Detection Limit
by Gajanan A. Bodkhe, Bhavna Hedau, Mayuri S. More, Myunghee Kim and Mahendra D. Shirsat
Chemosensors 2025, 13(7), 259; https://doi.org/10.3390/chemosensors13070259 - 16 Jul 2025
Viewed by 469
Abstract
A novel single-walled carbon nanotube (SWNT), silver (Ag) nanoparticle, and zinc benzene carboxylate (ZnBDC) metal–organic framework (MOF) composite was synthesised and systematically characterised to develop an efficient platform for mercury ion (Hg2+) detection. X-ray diffraction confirmed the successful incorporation of Ag [...] Read more.
A novel single-walled carbon nanotube (SWNT), silver (Ag) nanoparticle, and zinc benzene carboxylate (ZnBDC) metal–organic framework (MOF) composite was synthesised and systematically characterised to develop an efficient platform for mercury ion (Hg2+) detection. X-ray diffraction confirmed the successful incorporation of Ag nanoparticles and SWNTs without disrupting the crystalline structure of ZnBDC. Meanwhile, field-emission scanning electron microscopy and energy-dispersive spectroscopy mapping revealed a uniform elemental distribution. Thermogravimetric analysis indicated enhanced thermal stability. Electrochemical measurements (cyclic voltammetry and electrochemical impedance spectroscopy) demonstrated improved charge transfer properties. Electrochemical sensing investigations using differential pulse voltammetry revealed that the SWNTs/Ag@ZnBDC-modified glassy carbon electrode exhibited high selectivity toward Hg2+ ions over other metal ions (Cd2+, Co2+, Cr3+, Fe3+, and Zn2+), with optimal performance at pH 4. The sensor displayed a linear response in the concentration range of 0.1–1.0 nM (R2 = 0.9908), with a calculated limit of detection of 0.102 nM, slightly close to the lowest tested point, confirming its high sensitivity for ultra-trace Hg2+ detection. The outstanding sensitivity, selectivity, and reproducibility underscore the potential of SWNTs/Ag@ZnBDC as a promising electrochemical platform for detecting trace levels of Hg2+ in environmental monitoring. Full article
(This article belongs to the Special Issue Green Electrochemical Sensors for Trace Heavy Metal Detection)
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25 pages, 1160 KB  
Review
MS and GC–MS Analytical Methods for On-Line Thermally Induced Evolved Gas Analysis (OLTI-EGA)
by Giuseppina Gullifa, Elena Papa, Giordano Putzolu, Gaia Rizzo, Marialuisa Ruocco, Chiara Albertini, Roberta Risoluti and Stefano Materazzi
Chemosensors 2025, 13(7), 258; https://doi.org/10.3390/chemosensors13070258 - 16 Jul 2025
Viewed by 785
Abstract
Mass spectrometry (MS) and coupled gas chromatography-mass spectrometry (GC-MS) are globally recognized as the primary techniques for the analysis of gases or vapors due to their selectivity, sensitivity, accuracy, and reproducibility. When thermal stress is applied, vapors or gases are released as a [...] Read more.
Mass spectrometry (MS) and coupled gas chromatography-mass spectrometry (GC-MS) are globally recognized as the primary techniques for the analysis of gases or vapors due to their selectivity, sensitivity, accuracy, and reproducibility. When thermal stress is applied, vapors or gases are released as a result of the reactions and changes that occur. The analysis of these gases during the thermally induced reaction is scientifically referred to as evolved gas analysis (EGA), which is essential for confirming the occurrence of the induced reactions. Pyrolyzers, thermobalances, or simple heaters can increase the temperature of the analyzed samples according to a programmed and software-managed ramp, allowing for control over both the heating rate and isothermal stages. The atmosphere can also be varied to simulate pyrolysis or thermo-oxidative processes. This way, each induced reaction generates a unique evolved gas, which can be linked to a theoretically hypothesized mechanism. Mass spectrometry (MS) and coupled gas chromatography–mass spectrometry (GC-MS) are fundamental analytical methods used for on-line thermally induced evolved gas analysis (OLTI-EGA). Full article
(This article belongs to the Special Issue GC, MS and GC-MS Analytical Methods: Opportunities and Challenges (Third Edition))
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15 pages, 2463 KB  
Article
Measurement of the Effective Refractive Index of Suspensions Containing 5 µm Diameter Spherical Polystyrene Microparticles by Surface Plasmon Resonance and Scattering
by Osvaldo Rodríguez-Quiroz, Donato Luna-Moreno, Araceli Sánchez-Álvarez, Gabriela Elizabeth Quintanilla-Villanueva, Oscar Javier Silva-Hernández, Melissa Marlene Rodríguez-Delgado and Juan Francisco Villarreal-Chiu
Chemosensors 2025, 13(7), 257; https://doi.org/10.3390/chemosensors13070257 - 15 Jul 2025
Viewed by 449
Abstract
Microplastics (MP) have been found not only in the environment but also in living beings, including humans. As an initial step in MP detection, a method is proposed to measure the effective refractive index of a solution containing 5 µm diameter spherical polystyrene [...] Read more.
Microplastics (MP) have been found not only in the environment but also in living beings, including humans. As an initial step in MP detection, a method is proposed to measure the effective refractive index of a solution containing 5 µm diameter spherical polystyrene particles (SPSP) in distilled water, based on the surface plasmon resonance (SPR) technique and Mie scattering theory. The reflectances of the samples are obtained with their resonance angles and depths that must be normalized and adjusted according to the reference of the air and the distilled water, to subsequently find their effective refraction index corresponding to the Mie scattering theory. The system has an optical sensor with a Kretschmann–Raether configuration, consisting of a semicircular prism, a thin gold film, and a glass cell for solution samples with different concentrations (0.00, 0.20, 0.05, 0.50, and 1.00%). The experimental result provided a good linear fit with an R2 = 0.9856 and a sensitivity of 7.2863 × 10−5 RIU/% (refractive index unit per percentage of fill fraction). The limits of detection (LOD) and limit of quantification (LOQ) were determined to be 0.001% and 0.0035%, respectively. The developed optomechatronic system and its applications based on the SPR and Scattering enabled the effective measurement of the refractive index and concentration of solutions containing 5 µm diameter SPSP in distilled water. Full article
(This article belongs to the Special Issue Spectroscopic Techniques for Chemical Analysis)
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25 pages, 18692 KB  
Article
Hydrothermally Synthesized TiO2 Nanostructures for Electrochemical Detection of H2O2 in Barley (Hordeum vulgare) Under Salt Stress and Remediation with Fe3O4 Nanoparticles
by Irena Mihailova, Marina Krasovska, Eriks Sledevskis, Vjaceslavs Gerbreders, Jans Keviss, Valdis Mizers, Inese Kokina, Ilona Plaksenkova, Marija Jermalonoka and Aleksandra Mosenoka
Chemosensors 2025, 13(7), 256; https://doi.org/10.3390/chemosensors13070256 - 14 Jul 2025
Viewed by 518
Abstract
This study presents the development of a TiO2 nanowire-based electrochemical sensor for the selective and sensitive detection of hydrogen peroxide (H2O2) under neutral pH conditions, with a particular focus on its application in analyzing plant stress. The sensor [...] Read more.
This study presents the development of a TiO2 nanowire-based electrochemical sensor for the selective and sensitive detection of hydrogen peroxide (H2O2) under neutral pH conditions, with a particular focus on its application in analyzing plant stress. The sensor exhibited a linear detection range of 0–0.5 mM, a sensitivity of 0.0393 mA · mM−1, and a detection limit of 2.8 μM in phosphate-buffered saline solution (PBS, pH 7.4). This work’s main novelty lies in the systematic investigation of the relationship between TiO2 nanostructure morphology, which is controlled by hydrothermal synthesis parameters, and the resulting sensor performance. Interference studies confirmed excellent selectivity in the presence of common electroactive species found in plant samples, such as NaCl, KNO3, glucose, citric acid, and ascorbic acid. Real sample analysis using barley plant extracts grown under salt stress and treated with Fe3O4 nanoparticles confirmed the sensor’s applicability in complex biological matrices, enabling accurate quantification of endogenously produced H2O2. Endogenous H2O2 concentrations were found to range from near-zero levels in control and Fe3O4-only treated plants, to elevated levels of up to 0.36 mM in salt-stressed samples. These levels decreased to 0.25 and 0.15 mM upon Fe3O4 nanoparticle treatment, indicating a dose-dependent mitigation of stress. This finding was supported by genome template stability (GTS) analysis, which revealed improved DNA integrity in Fe3O4-treated plants. This study takes an integrated approach, combining the development of a nanostructured sensor with physiological and molecular stress assessment. The urgent need for tools to detect stress at an early stage and manage oxidative stress in sustainable agriculture underscores its relevance. Full article
(This article belongs to the Special Issue Electrochemical Sensors and Biosensors for Environmental Detection)
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25 pages, 6467 KB  
Article
Integrating Sensor Data, Laboratory Analysis, and Computer Vision in Machine Learning-Driven E-Nose Systems for Predicting Tomato Shelf Life
by Julia Marie Senge, Florian Kaltenecker and Christian Krupitzer
Chemosensors 2025, 13(7), 255; https://doi.org/10.3390/chemosensors13070255 - 12 Jul 2025
Viewed by 538
Abstract
Assessing the quality of fresh produce is essential to ensure a safe and satisfactory product. Methods to monitor the quality of fresh produce exist; however, they are often expensive, time-consuming, and sometimes require the destruction of the sample. Electronic Nose (E-Nose) technology has [...] Read more.
Assessing the quality of fresh produce is essential to ensure a safe and satisfactory product. Methods to monitor the quality of fresh produce exist; however, they are often expensive, time-consuming, and sometimes require the destruction of the sample. Electronic Nose (E-Nose) technology has been established to track the ripeness, spoilage, and quality of fresh produce. Our study developed a freshness monitoring system for tomatoes, combining E-Nose technology with storage condition monitoring, color analysis, and weight-loss tracking. Different post-purchase scenarios were investigated, focusing on the influence of temperature and mechanical damage on shelf life. Support Vector Classifier (SVC) and k-Nearest Neighbor (kNN) were applied to classify storage scenarios and storage days, while Support Vector Regression (SVR) and kNN regression were used for predicting storage days. By using a data fusion approach with Linear Discriminant Analysis (LDA), the SVC achieved an accuracy of 72.91% in predicting storage days and an accuracy of 86.73% in distinguishing between storage scenarios. The kNN yielded the best regression results, with a Mean Absolute Error (MAE) of 0.841 days and a coefficient of determination of 0.867. The results highlight the method’s potential to predict storage scenarios and storage days, providing insight into the product’s remaining shelf life. Full article
(This article belongs to the Special Issue Applications of Electronic Nose (E-Nose) and Electronic Tongue (E-Tongue) in Food Quality)
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16 pages, 3149 KB  
Article
Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample Analysis
by Alencastro Gabriel Ribeiro Lopes, Rafael Matias Silva, Orlando Fatibello-Filho and Tiago Almeida Silva
Chemosensors 2025, 13(7), 254; https://doi.org/10.3390/chemosensors13070254 - 12 Jul 2025
Viewed by 496
Abstract
Dopamine (DA) is a neurotransmitter responsible for important functions in mammals’ bodies, including mood, movement and motivation. High or low dopamine levels are associated mainly with mental illnesses such as schizophrenia and depression. Therefore, contributing to the development of electrochemical devices to precisely [...] Read more.
Dopamine (DA) is a neurotransmitter responsible for important functions in mammals’ bodies, including mood, movement and motivation. High or low dopamine levels are associated mainly with mental illnesses such as schizophrenia and depression. Therefore, contributing to the development of electrochemical devices to precisely determine the DA levels in urine samples, a simple and low-cost sensor is proposed in this work. The proposed sensor design is based on crosslinked chitosan films combining carbon black (CB) and deep eutectic solvents (DESs), incorporated onto the surface of a glassy carbon electrode (GCE). Fourier Transform Infrared Spectroscopy (FT-IR) was applied to characterize the produced DESs and their precursors, while the films were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The sensor modified with CB and DES–ethaline (DES (ETHA)-CB/GCE) showed a significantly enhanced analytical signal for DA using differential pulse voltammetry under the optimized working conditions. Moreover, a better heterogeneous electron transfer rate constant (k0) was obtained, about 45 times higher than that of the bare GCE. The proposed sensor achieved a linear response range of 0.498 to 26.8 µmol L−1 and limits of detection and quantification of 80.7 and 269 nmol L−1, respectively. Moreover, the sensor was successfully applied in the quantification of DA in the synthetic urine samples, with recovery results close to 100%. Furthermore, the sensor presented good precision, as shown from the repeatability tests. The presented method to electrochemically detect DA has proven to be efficient and simple compared to the conventional methods commonly reported. Full article
(This article belongs to the Special Issue Electrochemical Sensing in Medical Diagnosis)
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69 pages, 837 KB  
Review
Analytical Approaches Using GC-MS for the Detection of Pollutants in Wastewater Towards Environmental and Human Health Benefits: A Comprehensive Review
by Gonçalo Catarro, Rodrigo Pelixo, Mariana Feijó, Tiago Rosado, Sílvia Socorro, André R. T. S. Araújo and Eugenia Gallardo
Chemosensors 2025, 13(7), 253; https://doi.org/10.3390/chemosensors13070253 - 12 Jul 2025
Viewed by 933
Abstract
The analysis of wastewater is essential in environmental chemistry, particularly for monitoring emerging contaminants and assessing ecological impacts. In this context, hyphenated chromatographic techniques are widely used, with liquid chromatography being one of the most common. However, gas chromatography coupled with mass spectrometry [...] Read more.
The analysis of wastewater is essential in environmental chemistry, particularly for monitoring emerging contaminants and assessing ecological impacts. In this context, hyphenated chromatographic techniques are widely used, with liquid chromatography being one of the most common. However, gas chromatography coupled with mass spectrometry (GC-MS) remains a valuable tool in this field due to its sensitivity, selectivity, and widespread availability in most laboratories. This review examines the application of validated methods for wastewater analysis using GC-MS (MS), highlighting its relevance in identifying micropollutants such as pharmaceuticals, drugs of abuse, pesticides, hormones, and industrial by-products. The validation of analytical methods is crucial to ensuring the reliability and reproducibility of data and the accurate monitoring of contaminants. Key parameters, including sample volume, recovery efficiency, and detection and quantification limits, are discussed, evaluating different approaches to optimising the identification of different classes of contaminants. Additionally, this study explores advances in sample preparation techniques, such as solid-phase microextraction (SPME), dispersive liquid–liquid microextraction (DLLME), and solid-phase extraction (SPE), which enhance efficiency and minimise interferences in the analysis. Finally, future perspectives are discussed, including the integration of emerging technologies such as high-resolution mass spectrometry, the miniaturisation of GC systems, and the development of faster and more sustainable analytical methods. Full article
(This article belongs to the Special Issue GC, MS and GC-MS Analytical Methods: Opportunities and Challenges (Third Edition))
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15 pages, 2527 KB  
Article
A Disposable SWCNTs/AuNPs-Based Screen-Printed ISE at Different Temperatures to Monitor Ca2+ for Hypocalcemia Diagnosis
by Zhixue Yu, Hui Wang, Yue He, Ruipeng Chen, Xiangfang Tang and Benhai Xiong
Chemosensors 2025, 13(7), 252; https://doi.org/10.3390/chemosensors13070252 - 12 Jul 2025
Viewed by 455
Abstract
In this paper, screen-printed ion-selective electrodes combined with single-walled carbon nanotubes (SWCNTs) and gold nanoparticles (AuNPs) were used to rapidly and accurately measure serum Ca2+ concentration. Due to the susceptibility of cows to hypocalcemia after delivery, this disease can affect the health [...] Read more.
In this paper, screen-printed ion-selective electrodes combined with single-walled carbon nanotubes (SWCNTs) and gold nanoparticles (AuNPs) were used to rapidly and accurately measure serum Ca2+ concentration. Due to the susceptibility of cows to hypocalcemia after delivery, this disease can affect the health of cows and reduce milk production. Therefore, the development of an economical and swift detection method holds paramount importance for facilitating early diagnosis and subsequent treatment. In this study, by combining the high electrical conductivity and large surface area of SWCNTs with the strong catalytic activity of AuNPs, a SWCNTs/AuNPs composite with high sensitivity and good stability was prepared, achieving efficient selective recognition and signal conversion of Ca2+. The experimental results indicate that the screen-printed electrode modified with SWCNTs/AuNPs exhibited excellent performance in the determination of Ca2+ concentration. Its linear response range is 10−5.5–10−1 M, covering the normal and pathological concentration range of Ca2+ in cow blood, and the detection limit is far below the clinical detection requirements. In addition, the electrode also has good anti-interference ability and fast response time (about 15 s), showing good performance in the range of 5–45 °C. In practical applications, the combination of the electrode and portable detection equipment can realize the field rapid determination of cow blood Ca2+ concentration. This method is easy to operate, cost-effective, and easy to promote, providing strong technical support for the health management of dairy farms. Full article
(This article belongs to the Section Electrochemical Devices and Sensors)
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18 pages, 7559 KB  
Article
An Electrochemical Sensor for the Simultaneous Detection of Pb2+ and Cd2+ in Contaminated Seawater Based on Intelligent Mobile Detection Devices
by Zizi Zhao, Wei Qu, Chengjun Qiu, Yuan Zhuang, Kaixuan Chen, Yi Qu, Huili Hao, Wenhao Wang, Haozheng Liu and Jiahua Su
Chemosensors 2025, 13(7), 251; https://doi.org/10.3390/chemosensors13070251 - 11 Jul 2025
Viewed by 541
Abstract
Excessive levels of Pb2+ and Cd2+ in seawater pose significant combined toxicity to marine organisms, resulting in harmful effects and further threatening human health through biomagnification in the food chain. Traditional methods for detecting marine Pb2+ and Cd2+ rely [...] Read more.
Excessive levels of Pb2+ and Cd2+ in seawater pose significant combined toxicity to marine organisms, resulting in harmful effects and further threatening human health through biomagnification in the food chain. Traditional methods for detecting marine Pb2+ and Cd2+ rely on laboratory analyses, which are hindered by limitations such as sample degradation during transport and complex operational procedures. In this study, we present an electrochemical sensor based on intelligent mobile detection devices. By combining G-COOH-MWCNTs/ZnO with differential pulse voltammetry, the sensor enables the efficient, simultaneous detection of Pb2+ and Cd2+ in seawater. The G-COOH-MWCNTs/ZnO composite film is prepared via drop-coating and is applied to a glassy carbon electrode. The film is characterized using cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy, while Pb2+ and Cd2+ are quantified using differential pulse voltammetry. Using a 0.1 mol/L sodium acetate buffer (pH 5.5), a deposition potential of −1.1 V, and an accumulation time of 300 s, a strong linear correlation was observed between the peak response currents of Pb2+ and Cd2+ and their concentrations in the range of 25–450 µg/L. The detection limits were 0.535 µg/L for Pb2+ and 0.354 µg/L for Cd2+. The sensor was applied for the analysis of seawater samples from Maowei Sea, achieving recovery rates for Pb2+ ranging from 97.7% to 103%, and for Cd2+ from 97% to 106.1%. These results demonstrate that the sensor exhibits high sensitivity and stability, offering a reliable solution for the on-site monitoring of heavy metal contamination in marine environments. Full article
(This article belongs to the Section Electrochemical Devices and Sensors)
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16 pages, 4139 KB  
Article
Engineering Hierarchical CuO/WO3 Hollow Spheres with Flower-like Morphology for Ultra-Sensitive H2S Detection at ppb Level
by Peishuo Wang and Xueli Yang
Chemosensors 2025, 13(7), 250; https://doi.org/10.3390/chemosensors13070250 - 11 Jul 2025
Viewed by 434
Abstract
Highly sensitive real-time detection of hydrogen sulfide (H2S) is important for human health and environmental protection due to its highly toxic properties. The development of high-performance H2S sensors remains challenging for poor selectivity, high limit detection and slow recovery [...] Read more.
Highly sensitive real-time detection of hydrogen sulfide (H2S) is important for human health and environmental protection due to its highly toxic properties. The development of high-performance H2S sensors remains challenging for poor selectivity, high limit detection and slow recovery from irreversible sulfidation. To solve these problems, we strategically prepared a layered structure of CuO-sensitized WO3 flower-like hollow spheres with CuO as the sensitizing component. A 15 wt% CuO/WO3 exhibits an ultra-high response (Ra/Rg = 571) to 10 ppm H2S (131-times of pure WO3), excellent selectivity (97-times higher than 100 ppm interference gas), and a low detection limit (100 ppb). Notably, its fast response (4 s) is accompanied by full recovery within 236 s. After 30 days of continuous testing, the response of 15 wt% CuO/WO3 decreased slightly but maintained the initial response of 90.5%. The improved performance is attributed to (1) the p-n heterojunction formed between CuO and WO3 optimizes the energy band structure and enriches the chemisorption sites for H2S; (2) the reaction of H2S with CuO generates highly conductive CuS, which significantly reduces the interfacial resistance; and (3) the hierarchical flowery hollow microsphere structure, heterojunction, and oxygen vacancy synergistically promote the desorption. This work provides a high-performance H2S gas sensor that balances response, selectivity, and response/recovery kinetics. Full article
(This article belongs to the Special Issue Recent Progress in Nano Material-Based Gas Sensors)
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12 pages, 2279 KB  
Article
Electrostatic Self-Assembly of Heterostructured In2O3/Ti3C2Tx Nanocomposite for High-Selectivity NO2 Gas Sensing at Room Temperature
by Yongjing Guo, Zhengxin Zhang, Hangshuo Feng, Qingfu Dai, Qiuni Zhao, Zaihua Duan, Shenghui Guo, Li Yang, Ming Hou and Yi Xia
Chemosensors 2025, 13(7), 249; https://doi.org/10.3390/chemosensors13070249 - 10 Jul 2025
Viewed by 444
Abstract
Owing to high electrical conductivity, layered structure, and abundant surface functional groups, transition metal carbides/nitrides (MXenes) have received enormous interest in the field of gas sensors at room temperature. In this work, we synthesize a heterostructured nanocomposite with indium oxide (In2O [...] Read more.
Owing to high electrical conductivity, layered structure, and abundant surface functional groups, transition metal carbides/nitrides (MXenes) have received enormous interest in the field of gas sensors at room temperature. In this work, we synthesize a heterostructured nanocomposite with indium oxide (In2O3) decorated on titanium carbide (Ti3C2Tx) nanosheets by electrostatic self-assembly and develop it for high-selectivity NO2 gas sensing at room temperature. Self-assembly formation of multiple heterojunctions in the In2O3/Ti3C2Tx composite provide abundant NO2 gas adsorption sites and high electron transfer activity, which is conducive to improving the gas-sensing response of the In2O3/Ti3C2Tx gas sensor. Assisted by rich adsorption sites and hetero interface, the as-fabricated In2O3/Ti3C2Tx gas sensor exhibits the highest response to NO2 among various interference gases. Meanwhile, a detection limit of 0.3 ppm, and response/recovery time (197.62/93.84 s) is displayed at room temperature. Finally, a NO2 sensing mechanism of In2O3/Ti3C2Tx gas sensor is constructed based on PN heterojunction enhancement and molecular adsorption. This work not only expands the gas-sensing application of MXenes, but also demonstrates an avenue for the rational design and construction of NO2-sensing materials. Full article
(This article belongs to the Special Issue Functional Nanomaterial-Based Gas Sensors and Humidity Sensors)
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16 pages, 2888 KB  
Article
Vitamin K Epoxide Reductase Complex (VKORC1) Electrochemical Genosensors: Towards the Identification of 1639 G>A Genetic Polymorphism
by Tiago Barbosa, Stephanie L. Morais, Renato Carvalho, Júlia M. C. S. Magalhães, Valentina F. Domingues, Cristina Delerue-Matos, Hygor Ferreira-Fernandes, Giovanny R. Pinto, Marlene Santos and Maria Fátima Barroso
Chemosensors 2025, 13(7), 248; https://doi.org/10.3390/chemosensors13070248 - 10 Jul 2025
Viewed by 485
Abstract
Anticoagulants, including warfarin, are often administered to patients who are exhibiting early symptoms of thromboembolic episodes or who have already experienced such episodes. However, warfarin has a limited therapeutic index and might cause bleeding and other clinical problems. Warfarin inhibits the vitamin K [...] Read more.
Anticoagulants, including warfarin, are often administered to patients who are exhibiting early symptoms of thromboembolic episodes or who have already experienced such episodes. However, warfarin has a limited therapeutic index and might cause bleeding and other clinical problems. Warfarin inhibits the vitamin K epoxide reductase complex subunit 1 (VKORC1), an enzyme essential for activating vitamin K, in the coagulation cascade. Genetic factors, such as polymorphisms, can change the natural function of VKORC1, causing variations in the medication reaction among individuals. Hence, before prescribing warfarin, the patient’s genetic profile should also be considered. In this study, an electrochemical genosensor capable of detecting the VKORC1 1639 G>A polymorphism was designed and optimized. This analytical approach detects the electric current obtained during the hybridization reaction between two 52 base pair complementary oligonucleotide sequences. Investigating public bioinformatic platforms, two DNA sequences with the A and G single-nucleotide variants were selected and designed. The experimental protocol of the genosensor implied the formation of a bilayer composed of a thiolate DNA and an alkanethiol immobilized onto gold electrodes, as well as the formation of a DNA duplex using a sandwich-format hybridization reaction through a fluorescein labelled DNA signalling probe and the enzymatic amplification of the electrochemical signal, detected by chronoamperometry. A detection limit of 20 pM and a linear range of 0.05–1.00 nM was obtained. A clear differentiation between A/A, G/A and G/G genotypes in biological samples was successfully identified by his novel device. Full article
(This article belongs to the Special Issue Electrochemical Sensors and Biosensors for Food, Environmental and Biomedical Analysis)
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14 pages, 2441 KB  
Article
Reduced Graphene Oxide/β-Cyclodextrin Nanocomposite for the Electrochemical Detection of Nitrofurantoin
by Al Amin, Gajapaneni Venkata Prasad, Venkatachalam Vinothkumar, Seung Joo Jang, Da Eun Oh and Tae Hyun Kim
Chemosensors 2025, 13(7), 247; https://doi.org/10.3390/chemosensors13070247 - 10 Jul 2025
Cited by 1 | Viewed by 590
Abstract
In this work, a glassy carbon electrode (GCE) modified with reduced graphene oxide and β-cyclodextrin (rGO/β-CD) nanocomposite was developed for the electrochemical detection of nitrofurantoin (NFT). The structural and morphological characteristics of the synthesized nanocomposite were determined using scanning electron microscopy (SEM), Raman [...] Read more.
In this work, a glassy carbon electrode (GCE) modified with reduced graphene oxide and β-cyclodextrin (rGO/β-CD) nanocomposite was developed for the electrochemical detection of nitrofurantoin (NFT). The structural and morphological characteristics of the synthesized nanocomposite were determined using scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Moreover, the electrochemical behavior of the modified electrodes was thoroughly examined using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), with the rGO/β-CD-modified glassy carbon electrode (GCE) demonstrating superior electron transfer capability. Key experimental parameters, including scan rate, material loading, and solution pH, were systematically optimized. After optimizing the experimental conditions, the modified sensor showed excellent electrocatalytic performance and selectivity toward NFT, achieving a broad linear detection range from 0.5 to 120 μM, a low limit of detection (LOD) of 0.048 μM, and a high sensitivity of 12.1 µA µM–1 cm–2 using differential pulse voltammetry (DPV). Furthermore, the fabricated electrode exhibited good anti-interference ability, stability, precision, and real-time applicability for NFT detection in a wastewater sample. These results highlight the potential of the rGO/β-CD nanocomposite as a high-performance platform for electrochemical sensing applications. Full article
(This article belongs to the Special Issue Sensors for Food Testing, Environmental Analysis, and Medical Diagnostics)
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24 pages, 1871 KB  
Article
Data Analyses and Chemometric Modeling for Rapid Quality Assessment of Enriched Honey
by Jasenka Gajdoš Kljusurić, Vesna Knights, Berat Durmishi, Smajl Rizani, Vezirka Jankuloska, Valentina Velkovski, Ana Jurinjak Tušek, Maja Benković, Davor Valinger and Tamara Jurina
Chemosensors 2025, 13(7), 246; https://doi.org/10.3390/chemosensors13070246 - 9 Jul 2025
Cited by 1 | Viewed by 436
Abstract
The quality and authenticity of honey are of crucial importance for food safety and consumer confidence. Given the increasing interest in enriched honey and potential fraud, rapid and non-destructive analytical methods for quality assessment, such as Near-Infrared Spectroscopy (NIRS), are needed. Therefore, the [...] Read more.
The quality and authenticity of honey are of crucial importance for food safety and consumer confidence. Given the increasing interest in enriched honey and potential fraud, rapid and non-destructive analytical methods for quality assessment, such as Near-Infrared Spectroscopy (NIRS), are needed. Therefore, the aim of this work was to investigate the applicability of NIR spectroscopy coupled with chemometric methods to assess the quality change in honey from three different countries, after addition of five different aromatic plants (lavender, rosemary, oregano, sage, and white pine oil) in three different concentrations (0.5%, 0.8% and 1%). Measurements of basic physicochemical properties, color, antioxidant activity, and NIR spectra were performed for all samples (pure honey and honey with added aromatic plants). Chemometric models, such as Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression, were applied to analyze spectral data, correlate spectra with physicochemical properties, color and antioxidant activity measurements, and develop classification and prediction models. Spectral changes in the NIR region, as expected, showed the ability to distinguish samples depending on the type and concentration of added aromatic plants. Chemometric models enabled efficient discrimination between pure and enriched honey samples, as well as assessment of the influence of different additives on antioxidant activity and color. The results highlight the potential of NIRS as a rapid, non-destructive and environmentally friendly method for quality monitoring and detection of specific additives in honey, offering technical support for quality control and food safety regulation. Full article
(This article belongs to the Special Issue Chemometrics for Food, Environmental and Biological Analysis)
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16 pages, 3764 KB  
Article
Luminescence of Carbon Dots Induced by MeV Protons
by Mariapompea Cutroneo, Vladimir Havranek, Vaclav Holy, Petr Malinsky, Petr Slepicka, Selena Cutroneo and Lorenzo Torrisi
Chemosensors 2025, 13(7), 245; https://doi.org/10.3390/chemosensors13070245 - 9 Jul 2025
Viewed by 432
Abstract
In this study, we describe the preparation of carbon dots (CDs) from natural charcoal by laser ablation in a liquid. A continuum wave (CW) laser diode operating at a wavelength of 450 nm, hitting a solid carbon target placed into a biocompatible liquid, [...] Read more.
In this study, we describe the preparation of carbon dots (CDs) from natural charcoal by laser ablation in a liquid. A continuum wave (CW) laser diode operating at a wavelength of 450 nm, hitting a solid carbon target placed into a biocompatible liquid, constituted of a phosphate-buffered saline (PBS) solution and distilled water, was used for the generation of the CDs suspension. Exploring the practical applications of carbon dots, it was observed that the luminescence of the produced CDs can be used as bioimaging in living organisms, environmental monitoring, chemical analysis, targeted drug delivery, disease diagnosis, therapy, and others. The CDs’ luminescence can be induced by UV irradiation and, as demonstrated in this study, by energetic MeV proton beams. The fluorescence was revealed mainly at 480 nm when UV illuminated the CDs, and also in the region at 514–642 nm when the CDs were irradiated by energetic proton ions. Atomic force microscopy (AFM) of the CD films revealed their spherical shape with a size of about 10 nm. The significance of the manuscript lies in the use of CDs produced by laser ablation exhibiting luminescence under irradiation of an energetic proton beam. Full article
(This article belongs to the Section Materials for Chemical Sensing)
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40 pages, 12228 KB  
Article
Design and Synthesis of Arylboronic Acid Chemosensors for the Fluorescent-Thin Layer Chromatography (f-TLC) Detection of Mycolactone
by Gideon Atinga Akolgo, Benjamin M. Partridge, Timothy D. Craggs, Kingsley Bampoe Asiedu and Richard Kwamla Amewu
Chemosensors 2025, 13(7), 244; https://doi.org/10.3390/chemosensors13070244 - 9 Jul 2025
Viewed by 1262
Abstract
Fluorescent chemosensors are increasingly becoming relevant in recognition chemistry due to their sensitivity, selectivity, fast response time, real-time detection capability, and low cost. Boronic acids have been reported for the recognition of mycolactone, the cytotoxin responsible for tissue damage in Buruli ulcer disease. [...] Read more.
Fluorescent chemosensors are increasingly becoming relevant in recognition chemistry due to their sensitivity, selectivity, fast response time, real-time detection capability, and low cost. Boronic acids have been reported for the recognition of mycolactone, the cytotoxin responsible for tissue damage in Buruli ulcer disease. A library of fluorescent arylboronic acid chemosensors with various signaling moieties with certain beneficial photophysical characteristics (i.e., aminoacridine, aminoquinoline, azo, BODIPY, coumarin, fluorescein, and rhodamine variants) and a recognition moiety (i.e., boronic acid unit) were rationally designed and synthesised using combinatorial approaches, purified, and fully characterised using a set of complementary spectrometric and spectroscopic techniques such as NMR, LC-MS, FT-IR, and X-ray crystallography. In addition, a complete set of basic photophysical quantities such as absorption maxima (λabsmax), emission maxima (λemmax), Stokes shift (∆λ), molar extinction coefficient (ε), fluorescence quantum yield (ΦF), and brightness were determined using UV-vis absorption and fluorescence emission spectroscopy techniques. The synthesised arylboronic acid chemosensors were investigated as chemosensors for mycolactone detection using the fluorescent-thin layer chromatography (f-TLC) method. Compound 7 (with a coumarin core) emerged the best (λabsmax = 456 nm, λemmax = 590 nm, ∆λ = 134 nm, ε = 52816 M−1cm−1, ΦF = 0.78, and brightness = 41,197 M−1cm−1). Full article
(This article belongs to the Special Issue Advanced Colorimetric and Fluorescent Sensors and Their Application in Detection, 2nd Edition)
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27 pages, 690 KB  
Review
Phthalocyanine-Modified Electrodes Used in the Electroanalysis of Monoamine Neurotransmitters
by Anton Alexandru Ciucu, Mihaela Buleandră, Dana Elena Popa and Dragoș Cristian Ștefănescu
Chemosensors 2025, 13(7), 243; https://doi.org/10.3390/chemosensors13070243 - 7 Jul 2025
Viewed by 650
Abstract
Metallo-phthalocyanines (MPcs) are versatile materials with applications in electroanalysis because of their superior catalytic properties. This review presents the electrochemical methods based on MPc-modified electrodes and reports some of their remarkable properties and applications in the electroanalysis of monoamine neurotransmitters and biomolecules that [...] Read more.
Metallo-phthalocyanines (MPcs) are versatile materials with applications in electroanalysis because of their superior catalytic properties. This review presents the electrochemical methods based on MPc-modified electrodes and reports some of their remarkable properties and applications in the electroanalysis of monoamine neurotransmitters and biomolecules that play a crucial role in vital functions of the human body. The development of electrocatalytic chemically modified electrodes is based on their ability to provide a selective and rapid response toward a specific analyte in complex media without the need for sample pretreatment. The explanation of several phenomena occurring at the MPc-modified electrode surface (e.g., MPc-mediated electrocatalysis), the advantages of promoting different electron transfer reactions, and the detection mechanism are also presented. The types of MPcs and different materials, such as carbon nanotubes and graphene, used as substrates for modified working electrodes are discussed. Modifying the properties of MPcs through various interactions, or combining MPcs with carbonaceous materials, creates a synergistic effect. Such hybrid materials present both extraordinary catalytic and increased conductivity properties. We conducted a compilation study based on recent works to demonstrate the efficacy of the developed sensors and methods in sensing monoamine neurotransmitters. We emphasize the analyte type, optimized experimental parameters, working range, limits of detection and quantification, and application to real samples. MPc–carbon hybrids have led to the development of sensors with superior sensitivity and improved selectivity, enabling the detection of analytes at lower concentrations. We highlight the main advantages and drawbacks of the discussed methods. This review summarizes recent progress in the development and application of metallo-phthalocyanine-modified electrodes in the electroanalysis of monoamine neurotransmitters. Some possible future trends are highlighted. Full article
(This article belongs to the Special Issue New Electrodes Materials for Electroanalytical Applications)
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23 pages, 3823 KB  
Review
Electrochemical Strategies for MicroRNA Quantification Leveraging Amplification and Nanomaterials: A Review
by Alexander Hunt and Gymama Slaughter
Chemosensors 2025, 13(7), 242; https://doi.org/10.3390/chemosensors13070242 - 6 Jul 2025
Viewed by 711
Abstract
MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression and have emerged as critical biomarkers in various diseases, including cancer. Their stability in bodily fluids and role as oncogenes or tumor suppressors make them attractive targets for non-invasive diagnostics. However, conventional detection [...] Read more.
MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression and have emerged as critical biomarkers in various diseases, including cancer. Their stability in bodily fluids and role as oncogenes or tumor suppressors make them attractive targets for non-invasive diagnostics. However, conventional detection methods, such as Northern blotting, RT-PCR, and microarrays, are limited by low sensitivity, lengthy protocols, and limited specificity. Electrochemical biosensors offer a promising alternative, providing high sensitivity, rapid response times, portability, and cost-effectiveness. These biosensors translate miRNA hybridization events into quantifiable electrochemical signals, often leveraging redox-active labels, mediators, or intercalators. Recent advancements in nanomaterials and signal amplification strategies have further enhanced detection capabilities, enabling sensitive, label-free miRNA quantification. This review provides a comprehensive overview of the recent advances in electrochemical biosensing of miRNAs, emphasizing innovative redox-based detection strategies, probe immobilization techniques, and hybridization modalities. The critical challenges and future perspectives in advancing electrochemical miRNA biosensors toward clinical translation and point-of-care diagnostics are discussed. Full article
(This article belongs to the Special Issue Feature Review Papers in Chemical/Bio-Sensors and Analytical Chemistry in 2025)
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32 pages, 7710 KB  
Review
Illuminating Pollutants: The Role of Carbon Dots in Environmental Sensing
by Naveen Thanjavur and Young-Joon Kim
Chemosensors 2025, 13(7), 241; https://doi.org/10.3390/chemosensors13070241 - 6 Jul 2025
Viewed by 978
Abstract
The pursuit of cleaner environments and healthier ecosystems has driven the development of innovative strategies for detecting and mitigating toxic pollutants. Among emerging nanomaterials, carbon dots (CDs) have gained prominence due to their low toxicity, excellent biocompatibility, high fluorescence efficiency, and environmental sustainability. [...] Read more.
The pursuit of cleaner environments and healthier ecosystems has driven the development of innovative strategies for detecting and mitigating toxic pollutants. Among emerging nanomaterials, carbon dots (CDs) have gained prominence due to their low toxicity, excellent biocompatibility, high fluorescence efficiency, and environmental sustainability. This review critically analyzes the transformative role of CDs in environmental sensing and remediation. Highlighting their versatile applications, including bioimaging, photocatalysis, and sensitive biochemical sensing, we examine how CDs support the next generation of pollutant detection and degradation technologies, such as contaminant adsorption, membrane filtration, and photocatalytic breakdown. Furthermore, we discuss advances in sensor architectures integrating CDs and outline pathways for their expanded use in environmental monitoring. By mapping the intersection of nanotechnology, environmental science, and sensor innovation, this review anticipates future developments that could redefine pollution control through the strategic deployment of carbon dots. Full article
(This article belongs to the Special Issue Sensors for Food Testing, Environmental Analysis, and Medical Diagnostics)
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11 pages, 403 KB  
Article
Modeling the Frequency–Amplitude Characteristics of a Tunable SAW Oscillator
by Ionut Nicolae and Cristian Viespe
Chemosensors 2025, 13(7), 240; https://doi.org/10.3390/chemosensors13070240 - 6 Jul 2025
Viewed by 381
Abstract
The resonant frequency of an SAW oscillator can be modulated by varying the signal amplitude, due to non-linear acoustic interactions within the chemoselective layer. In this study, we developed an explicit model to describe the amplitude–frequency behavior of a tunable SAW oscillator. A [...] Read more.
The resonant frequency of an SAW oscillator can be modulated by varying the signal amplitude, due to non-linear acoustic interactions within the chemoselective layer. In this study, we developed an explicit model to describe the amplitude–frequency behavior of a tunable SAW oscillator. A polymeric layer of variable thickness was deposited in a circular area (radius 1.1 mm) at the center of the piezoactive surface. Increasing the oscillator loop attenuation resulted in a continuous increase in the resonant frequency by up to 1.8 MHz. The layer was modeled as a succession of non-interacting sub-layers of varying thicknesses. As a result, the function model consists of a superposition of terms, each corresponding to a layer region of distinct length and thickness. The maximum difference between the experimental data and function model (also known as residual of the fit) was below 1% (13.02 kHz) of the resonant frequency variation, thus supporting the validity of our approach. While our model proved successful, the results suggest that some interactions are unaccounted for, as evidenced by the periodicity of the residuals of fit and unrealistically large variation in acoustic wave velocity. Full article
(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)
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13 pages, 2602 KB  
Article
Hollow Mesoporous ZnO/ZnCo2O4 Based on Ostwald Ripening for H2S Detection
by Hongtao Wang, Yang Liu, Yuanchao Xie, Jianan Ma, Dan Han and Shengbo Sang
Chemosensors 2025, 13(7), 239; https://doi.org/10.3390/chemosensors13070239 - 5 Jul 2025
Viewed by 401
Abstract
Mesoporous ZnO/ZnCo2O4 nanocomposites with excellent gas-sensing performance were synthesized using the Ostwald ripening method. The as-prepared ZnO/ZnCo2O4 comprised aggregated monodisperse nanoparticles, and the nanoparticle size grew with increasing thermal treatment temperature. Increasing the calcination temperature did not [...] Read more.
Mesoporous ZnO/ZnCo2O4 nanocomposites with excellent gas-sensing performance were synthesized using the Ostwald ripening method. The as-prepared ZnO/ZnCo2O4 comprised aggregated monodisperse nanoparticles, and the nanoparticle size grew with increasing thermal treatment temperature. Increasing the calcination temperature did not significantly change the overall size of the ZnO/ZnCo2O4 nanocomposites, but the pore size and specific surface area were noticeably affected. The gas-sensing results showed that ZnO/ZnCo2O4 composites calcined at 500 °C exhibited the highest response to H2S at 200 °C, with a detection limit of 500 ppb. The ZnO/ZnCo2O4 composites also exhibited remarkable selectivity, response/recovery speed, and stability. Their excellent gas-sensing performance might be attributed to their porous structure, large specific surface area, and the heterogeneous interface between ZnO and ZnCo2O4. This work not only represents a new example of the Ostwald ripening-based formation of inorganic hollow structures in a template-free aqueous solution but also provides a novel and efficient sensing material for the detection of H2S gas. Full article
(This article belongs to the Special Issue Recent Progress in Nano Material-Based Gas Sensors)
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