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16 pages, 4725 KB

Open AccessArticle

A Ratiometric Fluorescence Sensor Based on BSA Assembled Gold–Silver Bimetallic Nanoclusters for Highly Selective Detection of Chlortetracycline in Water

by Yu-Meng Dai, Weidong Ruan and Hong-Wei Li

Chemosensors 2026, 14(3), 56; https://doi.org/10.3390/chemosensors14030056 - 2 Mar 2026

Viewed by 722

Abstract

This study reports the precise synthesis of red-emitting gold–silver bimetallic nanoclusters (Au-AgNCs) via a one-pot hydrothermal method using thiolactic acid as both the ligand and reducing agent. The Au-AgNCs possess an average diameter of 1.85 nm and exhibit strong fluorescence emission at 687 [...] Read more.

This study reports the precise synthesis of red-emitting gold–silver bimetallic nanoclusters (Au-AgNCs) via a one-pot hydrothermal method using thiolactic acid as both the ligand and reducing agent. The Au-AgNCs possess an average diameter of 1.85 nm and exhibit strong fluorescence emission at 687 nm. Furthermore, they display notable assembly-induced emission enhancement (AIEE) properties. Upon assembly with bovine serum albumin (BSA), their fluorescence quantum yield significantly increases from 2.50% to 7.78%. Then Au-AgNCs@BSA assembly was employed as a ratiometric fluorescence sensor for the detection of chlortetracycline (CTC). In the presence of CTC, the original red emission of the assembly at 687 nm remained stable, while a new blue emission emerged at 420 nm and intensified progressively with CTC concentration. The ratio of the two emission intensities (I₄₂₀/I₆₈₇) exhibited an excellent linear correlation with CTC concentration over the range of 0.10 to 15 μM, with a limit of detection (LOD) of 20 nM. Notably, the sensor demonstrated exceptional selectivity for CTC, showing negligible response to common interfering substances such as metal ions, anions, amino acids, and crucially, other tetracycline antibiotics (tetracycline, oxytetracycline, and doxycycline). The practical applicability of the sensor was validated through the determination of spiked CTC in real water samples, achieving satisfactory recovery rates. In conclusion, this work accomplishes two key objectives: the development of novel AIEE-active Au-Ag bimetallic nanoclusters and the design of an efficient ratiometric sensing strategy. This approach enables the highly selective and sensitive detection of CTC, offering a promising tool for environmental monitoring. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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18 pages, 5251 KB

Open AccessArticle

Green Synthesis of ZnO Nanoparticles Using Retama raetam Leaf Extract for VOC Sensing Applications

by Tarek Sekrafi, Mosaab Echabaane, Ahmadou Ly, Marc Debliquy, Chérif Dridi and Driss Lahem

Chemosensors 2026, 14(2), 42; https://doi.org/10.3390/chemosensors14020042 - 4 Feb 2026

Viewed by 1501

Abstract

The green synthesis of zinc oxide nanoparticles (ZnO NPs) using Retama raetam leaf extract via microwave irradiation was investigated. The biosynthesized NPs were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and [...] Read more.

The green synthesis of zinc oxide nanoparticles (ZnO NPs) using Retama raetam leaf extract via microwave irradiation was investigated. The biosynthesized NPs were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and UV-Vis spectrophotometry. An XRD pattern confirmed the formation of a hexagonal wurtzite structure. An FTIR analysis indicated the interactions of the NPs with bioactive molecules involved in their synthesis. SEM and STEM imaging determined the morphology of the NPs with an average size of 14 nm. Furthermore, the biosynthesized ZnO NPs were used as a sensitive layer for detecting volatile organic compounds (VOCs) at low concentrations ranging from 0.5 to 5 ppm. The response sensor measured at an optimum operating temperature of 250 °C and 50% relative humidity (RH). The sensor exhibited a strong response to 5 ppm ethanol (325%), a detection limit as low as 4 ppb and an excellent stability across varying humidity levels. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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16 pages, 6098 KB

Open AccessArticle

Eco-Friendly Synthesis and Paper Immobilization of AgNPs for Portable Colorimetric Detection of Hg²⁺ in Water

by Nevena Radivojević, Sanja Knežević, Stefan Graovac, Vladimir Rajić, Tamara Terzić, Nebojša Potkonjak, Tamara Lazarević-Pašti and Vedran Milanković

Chemosensors 2025, 13(12), 433; https://doi.org/10.3390/chemosensors13120433 - 16 Dec 2025

Cited by 2 | Viewed by 997

Abstract

Mercury’s severe toxicity and persistence demand fast, low-cost, and sustainable detection. In this work, a Juglans regia ethanolic extract is introduced as an efficient biogenic reducing and stabilizing agent for the green synthesis of silver nanoparticles (AgNPs). This plant-mediated route enables environmentally friendly [...] Read more.

Mercury’s severe toxicity and persistence demand fast, low-cost, and sustainable detection. In this work, a Juglans regia ethanolic extract is introduced as an efficient biogenic reducing and stabilizing agent for the green synthesis of silver nanoparticles (AgNPs). This plant-mediated route enables environmentally friendly nanoparticle formation with suitable optical properties for sensing applications. To overcome the poor visual selectivity observed in the colloidal AgNPs suspension, the nanoparticles were immobilized onto filter paper to produce a solid-phase colorimetric sensor. The paper-based platform exhibited a highly selective response toward Hg²⁺, showing complete suppression of the yellow coloration exclusively in the presence of Hg²⁺, even when challenged with a 200-fold excess of potentially interfering ions. Quantitative colorimetric analysis revealed a broad linear detection range from 1 × 10⁻⁸ to 1 × 10⁻³ mol dm⁻³ and an excellent limit of detection of 1.065 × 10⁻⁸ mol dm⁻³, with visible color changes consistent with the calculated values. The sensor’s performance was further validated using real tap water samples, with recovery values ranging from 96% to 102%, confirming minimal matrix interference and reliable quantification. Altogether, this study demonstrates that Juglans regia-mediated AgNPs, integrated into a simple paper-based format, provide a fully green, low-cost, and portable platform for sensitive and selective on-site detection of Hg²⁺ in environmental waters. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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18 pages, 1456 KB

Open AccessArticle

Eu-Doped Nickelate as a Platform for an Enzyme-Based Resistive Biosensor for Glucose

by Gilson P. Lopes, Jéssica H. H. Rossato, Neftali L. V. Carreno, Iseli L. Nantes and Marcia T. Escote

Chemosensors 2025, 13(11), 387; https://doi.org/10.3390/chemosensors13110387 - 3 Nov 2025

Cited by 2 | Viewed by 914

Abstract

Nickelate oxides show promise for biosensing applications, especially in glucose detection. Creating nickelate-based biosensors involves utilizing their electron-correlated structure and the metal–insulator (MI) transition, which endows them with unique electronic, magnetic, and catalytic properties. Chemical or oxygen vacancies can alter their conductivity and [...] Read more.

Nickelate oxides show promise for biosensing applications, especially in glucose detection. Creating nickelate-based biosensors involves utilizing their electron-correlated structure and the metal–insulator (MI) transition, which endows them with unique electronic, magnetic, and catalytic properties. Chemical or oxygen vacancies can alter their conductivity and catalytic activity, enabling redox-based detection. In this study, Nd_1−xEu_xNiO₃ films (0 < x < 0.35) functionalized with Glucose Oxidase (GOx) were tested for glucose sensing. Eu substitution shifts the MI transition temperature (T_MI) from 200 K (x = 0) to 340 K (x = 35). At room temperature, these films undergo a metallic-to-insulator phase transition, which, along with the Ni³⁺/Ni²⁺ ratios, influences their sensing capabilities. Time-resolved electrical resistance measurements monitored how glucose interacts with the film surfaces. The sample with x = 0.3 exhibited a measurable resistance change in response to glucose concentrations ranging from 10⁻¹² to 0.5 M, with a sensitivity of 9.1 mM⁻¹ and a limit of detection (LOD) of approximately 0.47 μM. Reproducibility and interference tests with other sugars yielded good results across all samples. Eu doping in NdNiO₃ enhances their sensing response, highlighting the importance of electronic state and MI transition in the sensing performance of these nickelate-based glucose sensors. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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20 pages, 5614 KB

Open AccessArticle

Heterostructures of CdSe Quantum Dots and g-C₃N₄ Applied as Electrochemiluminescent Probes for the Detection of Hydrogen Peroxide in Human Serum

by Roodney Alberto Carrillo Palomino, Aylén Di Tocco, Gastón Darío Pierini, Gabriela Valeria Porcal and Fernando Javier Arévalo

Chemosensors 2025, 13(5), 171; https://doi.org/10.3390/chemosensors13050171 - 7 May 2025

Cited by 1 | Viewed by 1354

Abstract

In this work, we developed a highly sensitive and reproducible electrochemiluminescent sensor based on a heterostructure of cadmium selenide quantum dots capped with 3-mercaptopropionic acid (MPA) + 3-morpholinoethanesulfonic acid (MES) (QDs CdSe) and carbon nitride nanosheets (g-C₃N₄) for the [...] Read more.

In this work, we developed a highly sensitive and reproducible electrochemiluminescent sensor based on a heterostructure of cadmium selenide quantum dots capped with 3-mercaptopropionic acid (MPA) + 3-morpholinoethanesulfonic acid (MES) (QDs CdSe) and carbon nitride nanosheets (g-C₃N₄) for the detection of H₂O₂ in lyophilized serum samples. To enhance the sensor sensitivity, g-C₃N₄ nanosheets were utilized as a platform to immobilize the QDs CdSe. An exhaustive characterization of the heterostructure was conducted, elucidating the interaction mechanism between QDs CdSe and g-C₃N₄. It was revealed that g-C₃N₄ acts as a hole (h⁺) donor, while QDs CdSe act as energy acceptors in a resonance energy transfer process, with the electrochemiluminescence emission originating from the QDs CdSe. The electrochemiluminescence intensity decreases in the presence of H₂O₂ due to the deactivation of the excited states of the QDs CdSe. This electrochemiluminescent sensor demonstrates exceptional performance for detecting H₂O₂ in aqueous systems, achieving a remarkably low limit of detection (LOD) of 1.81 nM, which is more sensitive than most reported sensors to detect H₂O₂. The applicability of the sensor was successfully tested where sub-µM levels of H₂O₂ were accurately quantified. These results highlight the potential of this electrochemiluminescent sensor as a reliable and pre-treatment-free tool for H₂O₂ detection in biochemical studies and human health applications. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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16 pages, 4066 KB

Open AccessArticle

Development of a Reliable Device for ‘Fluorokinetic’ Analysis Based on a Portable Diode Array MEMS Fluorimeter

by Domingo González-Arjona and Germán López-Pérez

Chemosensors 2025, 13(4), 128; https://doi.org/10.3390/chemosensors13040128 - 3 Apr 2025

Cited by 1 | Viewed by 3173

Abstract

A device was developed to study the evolution of fluorescence spectra as a function of time. A previously designed fluorimeter based on the diode array mini-spectrometer CM12880MA was used. The control and measurement were carried out by programming a SAM21D microcontroller. Considerations regarding [...] Read more.

A device was developed to study the evolution of fluorescence spectra as a function of time. A previously designed fluorimeter based on the diode array mini-spectrometer CM12880MA was used. The control and measurement were carried out by programming a SAM21D microcontroller. Considerations regarding the optimization of acquisition speed, memory, and computer interface have been analyzed and optimized. As a result, a very versatile device with great adaptability, reduced dimensions, portability, and a low budget (under EUR 500) has been built. The sensitivity, controlled by the integration time of the photodiodes, can be adjusted between 10 µs and 20 s, thus allowing sampling times ranging from 10 ms to more than 10 h. Under these conditions, chemical rate constants from 20 s⁻¹ to 10⁻⁸ s⁻¹ can be experimentally determined. It has a very wide operating range for the kinetic rate constant determination, over six orders of magnitude. As proof of the system performance, the oxidation reaction of Thiamine in a basic medium to form fluorescent Thiochrome has been employed. The evolution of the emission spectrum has been followed, and the decomposition rate constant has been measured at 2.1 × 10⁻³ s⁻¹, a value which matches those values reported in the literature for this system. A Thiochrome calibration curve has also been performed, obtaining a detection limit of 13 nM, consistent with literature data. Additionally, the stability of Thiochrome has been tested, being the photo-decomposition rate constants 1.8 × 10⁻⁴ s⁻¹ and 3.0 × 10⁻⁷ s⁻¹, in the presence and absence of UV light (365 nm), respectively. Finally, experiments have been designed to obtain, in a single measurement, the values of both rate constants: the formation of Thiochrome from Thiamine and its photo-decomposition under UV light to a non-fluorescent product. The rate constant values obtained are in good agreement with those previously obtained through independent experiments under the same experimental conditions. These results show that, under these conditions, Thiochrome can be considered an unstable intermediate in a chemical reaction with successive stages. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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13 pages, 6356 KB

Open AccessArticle

Detection of Ascorbic Acid in Tears with an Extended-Gate Field-Effect Transistor-Based Electronic Tongue Made of Electropolymerized Porphyrinoids on Laser-Induced Graphene Electrodes

by Kishore Pushparaj, Lorena Di Zazzo, Valerio Allegra, Rosamaria Capuano, Alexandro Catini, Gabriele Magna, Roberto Paolesse and Corrado Di Natale

Chemosensors 2025, 13(3), 108; https://doi.org/10.3390/chemosensors13030108 - 15 Mar 2025

Cited by 4 | Viewed by 2045

Abstract

Porphyrinoids are suitable sensitive materials for potentiometric electronic tongues. In this paper, we take advantage of these properties to develop an electronic tongue using an extended-gate field-effect transistor as a signal transducer. The sensitive films were made of different porphyrins and corroles electropolymerized [...] Read more.

Porphyrinoids are suitable sensitive materials for potentiometric electronic tongues. In this paper, we take advantage of these properties to develop an electronic tongue using an extended-gate field-effect transistor as a signal transducer. The sensitive films were made of different porphyrins and corroles electropolymerized in situ onto laser-induced graphene electrodes. The electronic tongue was duly characterized with respect to ascorbic acid, a common natural antioxidant. The sensors were shown to be sensitive and selective with respect to common interferents, such as dopamine and uric acid. Finally, the sensors were tested to detect ascorbic acid in artificial tears. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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21 pages, 4590 KB

Open AccessArticle

Investigating the Application of Pomegranate-Loaded Chitosan Nanoparticles as Contrast Agents for Enhancing Breast Cancer Detection via Diffuse Reflectance Spectroscopy

by Hala S. Abuelmakarem, Mohamed Aly Saad Aly, Shaza H. Aly, Sodfa Ayman, Muhammad Shamim Al Mamun and Omnia Hamdy

Chemosensors 2025, 13(2), 73; https://doi.org/10.3390/chemosensors13020073 - 17 Feb 2025

Cited by 4 | Viewed by 2617

Abstract

The present cancer diagnostic techniques and contrast agents suffer drawbacks, adverse effects, and poor compatibility with patients due to health variations. To improve the detection of breast cancer, this work examined and contrasted the prospective applications of pomegranates, chitosan nanoparticles (Cs NPs), and [...] Read more.

The present cancer diagnostic techniques and contrast agents suffer drawbacks, adverse effects, and poor compatibility with patients due to health variations. To improve the detection of breast cancer, this work examined and contrasted the prospective applications of pomegranates, chitosan nanoparticles (Cs NPs), and pomegranate-loaded chitosan nanoparticles (PCs NPs) as contrast agents for breast cancer, based on the diffuse reflectance properties at the following laser frequencies: red (670 nm) and near-infrared (700 and 808 nm) spectrum. Herein, a platform for the detection of breast cancer is proposed, offering a promising pathway for cancer detection. PCs NPs with two different pomegranate contents (2 and 5 g/L) were synthesized using the sol–gel method. The cytotoxicity of the developed nanomaterials on human normal (Vero) and breast cancer (MCF7) cell lines were evaluated in the presence of laser irradiation at 670 nm, and the fluorescent effect of the nanoparticles was observed. The chemical structures of the nanomaterials and pomegranate extract were analyzed using FTIR, and they were then further analytically characterized using dynamic light scattering, zeta potential, and field-emission scanning electron microscopy. Results confirmed the structural stability of the nanomaterials. Cytotoxicity measurements revealed that the nanomaterials achieved a selective cytotoxic effect toward tumor cells. Results also showed significant wavelength-dependent changes in diffuse reflectance characteristics between malignant and normal cells. PCs NPs, at a content of 5 g/L, enhanced the reflectance in malignant cells compared to normal cells of more than three folds. These findings indicate the potential of PCs NPs to distinguish between healthy and malignant cells based on the reflection measurements. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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10 pages, 1386 KB

Open AccessArticle

Rapid Isolation of Circulating Tumor Cells from Glioblastoma Patients Using a Lateral Filter Array Microfluidic Device

by Victória D’Amario Gavioli, Marcos Vilas Boas Filho, Gustavo R. Castro, Pedro Tadao Hamamoto Filho, Adriana Camargo Ferrasi and Valber A. Pedrosa

Chemosensors 2025, 13(2), 64; https://doi.org/10.3390/chemosensors13020064 - 11 Feb 2025

Cited by 3 | Viewed by 2617

Abstract

Glioblastoma is the most common form of brain cancer in adults, representing 35–40% of all malignant brain tumors. This highly aggressive malignancy originates in the central nervous system, and despite notable advancements in treatment strategies, it continues to be an incurable disease. The [...] Read more.

Glioblastoma is the most common form of brain cancer in adults, representing 35–40% of all malignant brain tumors. This highly aggressive malignancy originates in the central nervous system, and despite notable advancements in treatment strategies, it continues to be an incurable disease. The isolation of circulating tumor cells (CTC) at an early stage is challenging due to the low probability of their presence in peripheral blood. Detection and enumeration as early as possible can reportedly lead to more effective treatment. This study proposes a novel label-free, rapid, and continuous CTC separation device based on a lateral filter array microfluidic device for the highly efficient immunoaffinity isolation of CTCs. Our methodology successfully captured and isolated circulating tumor cells (CTCs) from the whole blood of glioblastoma (GBM) patients prior to surgery, achieving over 90% capture efficiency in under 40 min of analysis. These findings highlight the potential of this technology to enhance our understanding of the clinical significance of CTCs in the management of GBM in future research. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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11 pages, 1390 KB

Open AccessArticle

Pollution Monitoring via Potentiometric Membrane Sensors for the Determination of Chlorpromazine Hydrochloride in the Presence of Its Main Photo-Degradation Products in River Water

by Sherif A. Abdel-Gawad and Ali Altharawi

Chemosensors 2024, 12(11), 240; https://doi.org/10.3390/chemosensors12110240 - 17 Nov 2024

Viewed by 1660

Abstract

The utilization of membrane sensors for the monitoring and determination of pharmaceutical environmental pollutants has emerged as a crucial objective in recent years. Given the extensive use of chlorpromazine hydrochloride (CPZ) in medicine, its presence in the environment, particularly in surface water such [...] Read more.

The utilization of membrane sensors for the monitoring and determination of pharmaceutical environmental pollutants has emerged as a crucial objective in recent years. Given the extensive use of chlorpromazine hydrochloride (CPZ) in medicine, its presence in the environment, particularly in surface water such as rivers, is highly probable. Prolonged exposure of river water to sunlight and the photo-degradability of CPZ may enhance its photo-degradation. For the purpose of measuring CPZ in the presence of its primary photo-degradants, two sensitive and selective membrane electrodes were developed. These were synthesized utilizing two ion-pairing agents: sodium tetraphenylborate (TPB) and phosphotungstic acid (PTA). The electrodes exhibited a linear range that extended from 1 × 10⁻⁶ M to 1 × 10⁻² M. The membrane electrodes of CPZ-TPB and CPZ-PTA exhibited slopes of 59.90 ± 0.60 mV/decade and 58.90 ± 0.80 mV/decade, respectively. The sensors mentioned above showed acceptable performance in a pH range of 2.0 to 6.0. All test parameters were optimized to provide superior electrochemical performance. The fabricated membranes were effectively employed to sensitively quantify CPZ in the presence of its principal photodegradants. The developed sensors were successfully employed to quantify CPZ in river water samples without necessitating pre-treatment procedures. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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Review

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23 pages, 1146 KB

Open AccessReview

Real-Time Detection of Heavy Metals and Some Other Pollutants in Wastewater Using Chemical Sensors: A Strategy to Limit the Spread of Antibiotic-Resistant Bacteria

by Liliana Anchidin-Norocel, Anca Bosancu, Oana C. Iatcu, Andrei Lobiuc and Mihai Covasa

Chemosensors 2025, 13(9), 352; https://doi.org/10.3390/chemosensors13090352 - 12 Sep 2025

Cited by 9 | Viewed by 4122

Abstract

The increasing presence of heavy metals in wastewater is a growing environmental and public health concern, particularly due to their role in promoting the spread of antibiotic-resistant bacteria (ARB) through co-selection mechanisms. This review explores recent advances in real-time detection of heavy metals [...] Read more.

The increasing presence of heavy metals in wastewater is a growing environmental and public health concern, particularly due to their role in promoting the spread of antibiotic-resistant bacteria (ARB) through co-selection mechanisms. This review explores recent advances in real-time detection of heavy metals and some other pollutants using chemical sensors as a strategic tool to limit ARB proliferation. It provides an overview of sensor types, including electrochemical, optical, biosensors, and molecularly imprinted polymer (MIP) sensors, and assesses their suitability for monitoring pollutants in complex wastewater matrices. Emphasis is placed on the integration of these technologies with Internet of Things (IoT) platforms, portable and autonomous systems, and data-driven approaches for multi-metal detection, selectivity enhancement, and predictive analysis. The review also discusses current challenges such as sensor stability, interference, and cost-efficiency, and outlines future directions in real-time environmental monitoring and antibiotic resistance control. Overall, chemical sensor-based monitoring offers a promising, scalable solution for safeguarding ecosystems and public health in the face of growing antimicrobial resistance. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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37 pages, 4685 KB

Open AccessReview

Gate Engineering in Two-Dimensional (2D) Channel FET Chemical Sensors: A Comprehensive Review of Architectures, Mechanisms, and Materials

by Ganapathi Bharathi and Seongin Hong

Chemosensors 2025, 13(6), 217; https://doi.org/10.3390/chemosensors13060217 - 13 Jun 2025

Cited by 6 | Viewed by 5343

Abstract

Field-effect transistor (FET) chemical sensors are essential for enabling sophisticated lifestyles and ensuring safe working environments. They can detect a wide range of analytes, including gaseous species (NO₂, NH₃, VOCs), ionic compounds, and biological molecules. Among the structural components [...] Read more.

Field-effect transistor (FET) chemical sensors are essential for enabling sophisticated lifestyles and ensuring safe working environments. They can detect a wide range of analytes, including gaseous species (NO₂, NH₃, VOCs), ionic compounds, and biological molecules. Among the structural components of FETs, the gate configuration plays a vital role in controlling the semiconductor channel’s electrostatic environment, thereby strongly influencing sensing performance. Two-dimensional (2D) materials offer additional advantages in these sensors due to their rich surface chemistry and high sensitivity to external interactions. This review offers a comprehensive classification of 2D channel FET chemical sensors based on their gate configurations. Their working principles, fabrication strategies, and sensing performance are discussed in detail. A critical analysis of the advantages and challenges associated with each gate configuration is performed. This review aims to guide future research on the selection of appropriate device configurations for the development of excellent FET chemical sensors. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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36 pages, 2458 KB

Open AccessReview

Limonene Detection in the Exhaled Human Breath Providing an Early Diagnosis Method of Liver Diseases

by Erich Kny, Christoph Kleber and Wiktor Luczak

Chemosensors 2025, 13(6), 204; https://doi.org/10.3390/chemosensors13060204 - 3 Jun 2025

Viewed by 5300

Abstract

This review aims to summarize possible methods for the detection of limonene in the gas phase at low to very low concentrations. Limonene has historically been of interest as a fragrance in cosmetics, the food industry, pharmaceutics, and the production of solvents. The [...] Read more.

This review aims to summarize possible methods for the detection of limonene in the gas phase at low to very low concentrations. Limonene has historically been of interest as a fragrance in cosmetics, the food industry, pharmaceutics, and the production of solvents. The development of analytical methods for limonene was initially driven by its use in relevant industries such as chemical, pharmaceutics, cosmetics, food, agriculture, and forestry. More recently, it has been recognized as a potent biomarker for human metabolic conditions, such as liver disease and certain cancers. The interest in improved limonene detection in exhaled human breath has increased, particularly from the medical field, which demands high reliability, very low detection limits in the parts per billion (ppb) and even parts per trillion (ppt) range, and excellent selectivity against other exhaled volatile organic compounds (VOC). In addition, the detection methods should be portable and affordable to facilitate potential mass screening. This review paper aims to explore all possible detection methods by evaluating their proven analytical capabilities for limonene or discussing their potential usefulness, benefits, and applicability for limonene detection. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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31 pages, 6110 KB

Open AccessReview

Recent Progress on Rare Earth Orthoferrites for Gas-Sensing Applications

by Ganesh Kotnana and Seongin Hong

Chemosensors 2025, 13(5), 156; https://doi.org/10.3390/chemosensors13050156 - 23 Apr 2025

Cited by 1 | Viewed by 1815

Abstract

Gas-sensing technology is crucial for the detection of toxic and harmful gases to ensure environmental safety and human health. Gas sensors convert the changes in the conductivity of the sensing material resulting from the adsorption of gas molecules into measurable electrical signals. Rare [...] Read more.

Gas-sensing technology is crucial for the detection of toxic and harmful gases to ensure environmental safety and human health. Gas sensors convert the changes in the conductivity of the sensing material resulting from the adsorption of gas molecules into measurable electrical signals. Rare earth orthoferrite-based perovskite oxides have emerged as promising candidates for gas-sensing technology owing to their exceptional structural, optical, and electrical properties, which enable the detection of various gases. In this article, we review the latest developments in orthoferrite-based gas sensors in terms of sensitivity, selectivity, stability, operating temperature, and response and recovery times. It begins with a discussion on the gas-sensing mechanism of orthoferrites, followed by a critical emphasis on their nanostructure, doping effects, and the formation of nanocomposites with other sensing materials. Additionally, the role of the tunable bandgap and different porous morphologies with a high surface area of the orthoferrites on their gas-sensing performance were explored. Finally, we identified the current challenges and future perspectives in the gas-sensing field, such as novel doping strategies and the fabrication of miniaturized gas sensors for room-temperature operation. Full article

(This article belongs to the Special Issue Chemical Sensors for Bio-Medical and Environmental Applications, 2nd Edition)

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