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Chemosensors
Volume 12
Issue 11
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Chemosensors, Volume 12, Issue 11 (November 2024) – 22 articles

Cover Story (view full-size image): The bacterial bioluminescence system enables autonomous light production in mammalian cells, allowing bioluminescence imaging without externally supplied substrates. Light emission of this system is dependent on the cellular availability of the involved substrates and cofactors, including FMN and NADPH. In this work, it is shown that the overexpression of two proteins that increase the cellular concentrations of FMN and NADPH, respectively, improves bioluminescence levels up to 2.4-fold. The enhanced light emission enables bioluminescence imaging of mammalian cells with increased sensitivity and spatial and temporal resolution. View this paper
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12 pages, 2266 KiB  
Article
A Nanodiamond-Based Electrochemical Sensor for the Determination of Paracetamol in Pharmaceutical Samples
by Déborah de Oliveira Lopes, Felipe Magalhães Marinho, Patricia Batista Deroco, Amanda Neumann, Jessica Rocha Camargo, Rafaela Cristina de Freitas, Lucas Ventosa Bertolim, Orlando Fatibello Filho, Bruno Campos Janegitz and Geiser Gabriel de Oliveira
Chemosensors 2024, 12(11), 243; https://doi.org/10.3390/chemosensors12110243 - 20 Nov 2024
Viewed by 868
Abstract
This study presents an electrochemical sensor developed from a glassy carbon electrode modified with nanodiamond film (ND/GCE). This electrochemical response of the proposed sensor was improved, and it showed excellent analytical performance for the detection of paracetamol (PAR), which was attributed to the [...] Read more.
This study presents an electrochemical sensor developed from a glassy carbon electrode modified with nanodiamond film (ND/GCE). This electrochemical response of the proposed sensor was improved, and it showed excellent analytical performance for the detection of paracetamol (PAR), which was attributed to the high PAR charging capacity on the electrode surface and the excellent electrical conductivity of ND. Morphological and electrochemical characterizations of the sensor were performed via scanning electron microscopy (SEM) and cyclic voltammetry using a redox probe [Fe(CN)6]3−. The sensor was applied for the determination of PAR. Quantification was performed using square-wave voltammetry, and it showed a linear concentration range from 0.79 to 100 µmol L−1, with a limit of detection of 0.18 µmol L−1. The proposed sensor exhibited satisfactory repeatability and high sensitivity in the determination of the analyte of interest. The electrochemical sensor was also employed for the analysis of PAR in real samples, with recovery rates ranging between 96.4 and 98.7%. This sensor was successfully used for the determination of the drug in pharmaceutical samples. Full article
(This article belongs to the Special Issue Carbon Nanomaterials and Related Materials for Sensing Applications, Volume II)
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7 pages, 1466 KiB  
Communication
Enhancing the Spectral Sensitivity of Prism-Based SPR Sensors: The Role of Analyte RI
by Wenyuan Wang, Tianfa Liao, Hongxiang Lin, Han Cui and Xiaohui Wei
Chemosensors 2024, 12(11), 242; https://doi.org/10.3390/chemosensors12110242 - 20 Nov 2024
Viewed by 601
Abstract
A theoretical approach is presented to significantly enhance the spectral sensitivity of prism-based SPR sensors. The spectral sensitivity of prism-based SPR sensors is derived based on the coupling conditions of SPR and might exceed 105 nm/RIU for analytes with large RI values [...] Read more.
A theoretical approach is presented to significantly enhance the spectral sensitivity of prism-based SPR sensors. The spectral sensitivity of prism-based SPR sensors is derived based on the coupling conditions of SPR and might exceed 105 nm/RIU for analytes with large RI values when other sensor parameters are carefully considered, including the RI of the prism, the angle of incidence, and the SPR active material. The spectral sensitivity could be markedly enhanced, reaching up to 10,000 nm/RIU by fine-tuning the effective RI of the incident light to be slightly larger, specifically 0.01~0.02 RIU, than the RI of the analyte, which is attributed to the large dielectric permittivity of the SPR active material, the key factor for achieving high sensitivity. The dynamic range is 0.040 RIU in the case of high sensitivity, which is sufficient in most applications. Moreover, the spectral sensitivity could be pushed even higher, into the range of 106~108 nm/RIU, by positioning the effective RI of the incident light closer to that of the analyte. However, it requires a careful balance between optimizing the sensitivity and maintaining an acceptable dynamic range. Full article
(This article belongs to the Special Issue Advanced Surface Plasmon Resonance Sensors)
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13 pages, 1717 KiB  
Article
Cleavage Reaction Lateral Flow Assays for Salivary Pepsin Measurement Using a Pepsin-Susceptible Peptide Substrate
by Sung-Woong Kang, Young Ju Lee, Jae-Chul Lee, Young-Gyu Eun and Gi-Ja Lee
Chemosensors 2024, 12(11), 241; https://doi.org/10.3390/chemosensors12110241 - 20 Nov 2024
Viewed by 626
Abstract
In this study, we introduce a novel cleavage reaction lateral flow assay (LFA) based on pepsin activity against a pepsin-susceptible peptide (PSP) substrate to detect salivary pepsin. Two types of cleavage reaction LFAs, the within-tube and on-strip cleavage reactions, were prepared based on [...] Read more.
In this study, we introduce a novel cleavage reaction lateral flow assay (LFA) based on pepsin activity against a pepsin-susceptible peptide (PSP) substrate to detect salivary pepsin. Two types of cleavage reaction LFAs, the within-tube and on-strip cleavage reactions, were prepared based on the PSP and pepsin reaction location. In the within-tube cleavage reaction LFA, samples were treated in the microtube within a heating block for 30 min separately and subsequently developed with running buffer in the LFA. For the on-strip cleavage reaction, samples were treated on the reaction zone of the strip within the heating zone of the multifunctional strip cassette for 10 min. After developing the running buffer in the LFA, the assay image was obtained using a universal mobile reader with a multifunctional strip cassette. The within-tube cleavage reaction LFA showed high sensitivity (limit of detection [LOD] 1.9 ng/mL), good specificity, and high reproducibility. This assay exhibited better linearity in the log concentration range of pepsin (4–500 ng/mL) than a commercially available dipstick assay. The on-strip cleavage reaction LFA showed a similar sensitivity (LOD 1.4 ng/mL) to that of the within-tube reaction assay. Therefore, we expect these cleavage reaction LFAs using PSP to be utilized as simple and effective tools to detect salivary pepsin. Full article
(This article belongs to the Special Issue Rapid Point-of-Care Testing Technology and Application)
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11 pages, 1390 KiB  
Article
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 586
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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10 pages, 7589 KiB  
Communication
A Theoretical Examination of Various Complexes of a Proposed Novel Chemosensor Material—Graphene/SiC
by Dobromir A. Kalchevski, Stefan Kolev, Dimitar Dimov, Dimitar Trifonov, Ivalina Avramova, Pavlina Ivanova and Teodor Milenov
Chemosensors 2024, 12(11), 239; https://doi.org/10.3390/chemosensors12110239 - 17 Nov 2024
Viewed by 743
Abstract
The potential of semiconducting, corrugated graphene, grown on silicon carbide, as an active element in chemosensors is studied in the present work. For this purpose, the adsorption of benzene, diazepam and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the material’s surface was modeled. According to [...] Read more.
The potential of semiconducting, corrugated graphene, grown on silicon carbide, as an active element in chemosensors is studied in the present work. For this purpose, the adsorption of benzene, diazepam and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the material’s surface was modeled. According to the graphene sheet bending and adsorbate–adsorbent distances, the heterostructure favors the ligands in the order of diazepam < benzene < TCDD. The apparent ambiguity in the results for diazepam is easy to explain. The abundance of lone pairs and π-electrons compensates for the low-symmetry, non-planar, far from optimal (adsorption-wise) geometry. The maximum band gap change in the heterostructure, caused by adsorption, is 0.02 eV. Intermolecular binding does not alter the HOMO–LUMO difference in benzene and TCDD by more than 0.01 eV. The completely planar molecules are not expected to undergo significant geometrical changes; hence, the alteration in their frontier orbitals is also minimal. The adsorption of diazepam, however, causes significant changes in the projected density of states of both structures in the complex. In conclusion, corrugated graphene is applicable as an active material in selective chemosensors for non-planar aromatic molecules. Full article
(This article belongs to the Special Issue Recent Advances in Electrode Materials for Electrochemical Sensing)
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12 pages, 8606 KiB  
Article
CO2 Interaction Mechanism of SnO2-Based Sensors with Respect to the Pt Interdigital Electrodes Gap
by Adelina Stanoiu, Alexandra Corina Iacoban, Catalina Gabriela Mihalcea, Ion Viorel Dinu, Ovidiu Gabriel Florea, Ioana Dorina Vlaicu and Cristian Eugen Simion
Chemosensors 2024, 12(11), 238; https://doi.org/10.3390/chemosensors12110238 - 16 Nov 2024
Viewed by 751
Abstract
The tuning sensitivity towards CO2 detection under in-field-like conditions was investigated using SnO2-sensitive material deposited onto Al2O3 substrates provided with platinum electrodes with interdigital gaps of 100 µm and 30 µm. X-ray diffraction, low-magnification and high-resolution transmission [...] Read more.
The tuning sensitivity towards CO2 detection under in-field-like conditions was investigated using SnO2-sensitive material deposited onto Al2O3 substrates provided with platinum electrodes with interdigital gaps of 100 µm and 30 µm. X-ray diffraction, low-magnification and high-resolution transmission electron microscopy, and electrical and contact potential difference investigations were employed to understand the sensing mechanism involved in CO2 detection. The morpho-structural analysis revealed that the SnO2 nanoparticles exhibit well-defined facets along the (110) and (101) crystallographic planes. Complex phenomenological investigations showed that moisture significantly affects the gas sensing performance. The experimental results corroborated the literature evidence, highlighting the importance of Pt within the interdigital electrodes subsequently reflected in the increase in the CO2 sensing performance with the decrease in the interdigital gap. The catalytic efficiency is explained by the distribution of platinum at the gas-Pt-SnO2 three-phase boundary, which is critical for enhancing the sensor performance. Full article
(This article belongs to the Special Issue Advanced Chemical Sensors for Gas Detection)
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18 pages, 3344 KiB  
Article
Low-Cost Electrochemical Determination of L-Ascorbic Acid Using Screen-Printed Electrodes and Development of an Electronic Tongue for Juice Analysis
by Laila El Anzi, María Soledad García, Eduardo Laborda, Alberto Ruiz and Joaquín Ángel Ortuño
Chemosensors 2024, 12(11), 237; https://doi.org/10.3390/chemosensors12110237 - 16 Nov 2024
Viewed by 599
Abstract
Low-cost electrochemical methodologies for the determination of L-ascorbic acid (vitamin C) and the analysis of juices are developed based on its electro-oxidation on carbon screen-printed electrodes. A novel chronoamperometric methodology is developed for the quantification of L-ascorbic acid in fruit juices. The proposed [...] Read more.
Low-cost electrochemical methodologies for the determination of L-ascorbic acid (vitamin C) and the analysis of juices are developed based on its electro-oxidation on carbon screen-printed electrodes. A novel chronoamperometric methodology is developed for the quantification of L-ascorbic acid in fruit juices. The proposed method stands out for its simplicity and rapidity, demonstrating its efficacy in determining L-ascorbic acid content in various fruit juices. Notably, the results obtained with this chronoamperometric approach are compared with those yielded by chromatography, with no significant differences between the two methods being found. Additionally, an electronic tongue is developed for the differentiation of juices based on the square wave voltammetric signals. Full article
(This article belongs to the Special Issue Low-Cost Chemosenors for Applications in Environment, Health, Food, and Industry Process Control)
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20 pages, 2452 KiB  
Review
Functional Organic Electrochemical Transistor-Based Biosensors for Biomedical Applications
by Zhiyao Wang, Minggao Liu, Yundi Zhao, Yating Chen, Beenish Noureen, Liping Du and Chunsheng Wu
Chemosensors 2024, 12(11), 236; https://doi.org/10.3390/chemosensors12110236 - 13 Nov 2024
Viewed by 1056
Abstract
Organic electrochemical transistors (OECTs), as an emerging device for the development of novel biosensors, have attracted more and more attention in recent years, demonstrating their promising prospects and commercial potential. Functional OECTs have been widely applied in the field of biosensors due to [...] Read more.
Organic electrochemical transistors (OECTs), as an emerging device for the development of novel biosensors, have attracted more and more attention in recent years, demonstrating their promising prospects and commercial potential. Functional OECTs have been widely applied in the field of biosensors due to their decisive advantages, such as high transconductance, easy functionalization, and high integration capability. Therefore, this review aims to provide a comprehensive summary of the most recent advances in the application of functional OECT-based biosensors in biomedicine, especially focusing on those biosensors for the detection of physiological and biochemical parameters that are critical for the health of human beings. First, the main components and basic working principles of OECTs will be briefly introduced. In the following, the strategies and key technologies for the preparation of functional OECT-based biosensors will be outlined and discussed with regard to the applications of the detection of various targets, including metabolites, ions, neurotransmitters, electrophysiological parameters, and immunological molecules. Finally, the current main issues and future development trends of functional OECT-based biosensors will be proposed and discussed. The breakthrough in functional OECT-based biosensors is believed to enable such devices to achieve higher performance, and thus, this technology could provide new insight into the future field of medical and life sciences. Full article
(This article belongs to the Special Issue Advancements of Chemical and Biosensors in China—2nd Edition)
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22 pages, 1683 KiB  
Review
Algal Biosensors for Detection of Potentially Toxic Pollutants and Validation by Advanced Methods: A Brief Review
by Diego Serrasol do Amaral, Luana Vaz Tholozan, Daisa Hakbart Bonemann, Cristina Jansen-Alves, Wiliam Boschetti, Diogo La Rosa Novo, Neftali Lenin Villarreal Carreno and Claudio Martin Pereira de Pereira
Chemosensors 2024, 12(11), 235; https://doi.org/10.3390/chemosensors12110235 - 13 Nov 2024
Viewed by 912
Abstract
The presence of potentially toxic pollutants, such as pesticides and metal ions, even at low concentrations, can significantly impact aquatic environmental health. This pollution is a globally widespread problem and requires fast and reliable analysis, especially for in-situ identification/quantification. Atomic absorption spectrometry and [...] Read more.
The presence of potentially toxic pollutants, such as pesticides and metal ions, even at low concentrations, can significantly impact aquatic environmental health. This pollution is a globally widespread problem and requires fast and reliable analysis, especially for in-situ identification/quantification. Atomic absorption spectrometry and plasma-based spectrometry techniques have been considered the most analytical tools used to monitor potentially toxic metal ions in aquatic media and other related matrices. The dynamics of global climate change and its correlation with pollution, especially from anthropogenic sources, have encouraged the development of other faster analytical tools for monitoring these pollutants. A noteworthy alternative for determining potentially toxic pollutants is using algae-based biosensors, resulting in a cost reduction and simplification of environmental analysis, enabling a more reliable comprehension of the role of humans in climate change. These biosensors, which may not have the highest sensitivity in quantification, have demonstrated remarkable potential in the identification of potentially toxic pollutants and several field applications. Biosensors can be an excellent biotechnology solution for monitoring global environmental changes. Thus, this review highlights the main advances in developing and comparing algae-based biosensors and other analytical possibilities for the identification of potentially toxic pollutants and their possible applications in environmental analysis. Full article
(This article belongs to the Collection pH Sensors, Biosensors and Systems)
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45 pages, 9504 KiB  
Review
Nanomaterial-Based Electrochemical Sensors for the Detection of Pharmaceutical Drugs
by Shweta J. Malode, Mohammed Ali Alshehri and Nagaraj P. Shetti
Chemosensors 2024, 12(11), 234; https://doi.org/10.3390/chemosensors12110234 - 11 Nov 2024
Viewed by 1637
Abstract
The rapidly increasing human population has led to new biological and environmental challenges. These challenges, in turn, have contributed to the rapid growth of the pharmaceutical sector. Quality control in pharmaceutical manufacturing and drug delivery necessitates portable, sensitive, precise, and cost-effective devices to [...] Read more.
The rapidly increasing human population has led to new biological and environmental challenges. These challenges, in turn, have contributed to the rapid growth of the pharmaceutical sector. Quality control in pharmaceutical manufacturing and drug delivery necessitates portable, sensitive, precise, and cost-effective devices to monitor patient dosing and assess pharmaceutical hazards. This study highlights the attributes and applications of the current nanomaterial-based sensors for drug detection, emphasizing the potential of these devices to advance the detection of bioactive molecules, thereby promoting human health and environmental protection on a large scale. Electrochemical sensors, in particular, have become invaluable in bioimaging, electrochemical analysis, and drug delivery due to their high specificity, selectivity, and stability across cycles. This review focuses on recent advancements in electrochemical devices for healthcare applications, detailing their production, analytical performance, and clinical uses. Full article
(This article belongs to the Special Issue Feature Review Papers in Chemical/Bio-Sensors and Analytical Chemistry in 2024)
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18 pages, 4007 KiB  
Review
Development of a Chemical Sensor Device for Monitoring Hazardous Gases Generated in the Semiconductor Manufacturing Process
by My Thi Ngoc Nguyen and Jun Seop Lee
Chemosensors 2024, 12(11), 233; https://doi.org/10.3390/chemosensors12110233 - 9 Nov 2024
Viewed by 1064
Abstract
The semiconductor industry plays a crucial role in various fields but also contributes to environmental degradation. Throughout the semiconductor chip manufacturing process, hazardous gases are released at each stage, despite stringent treatment procedures. These gases can be categorized into four groups: acidic and [...] Read more.
The semiconductor industry plays a crucial role in various fields but also contributes to environmental degradation. Throughout the semiconductor chip manufacturing process, hazardous gases are released at each stage, despite stringent treatment procedures. These gases can be categorized into four groups: acidic and alkaline gases, volatile organic compounds, flammable and corrosive gases, and greenhouse gases. To meet stricter emission standards, further advancements in gas sensor technology are essential. This review examines recent research on monitoring these gases, highlighting the capabilities and limitations of existing sensor technologies. Additionally, the paper discusses current challenges in gas sensing research and proposes future directions for improving technologies. Full article
(This article belongs to the Special Issue Gas Sensors for Monitoring Environmental Changes, 2nd Edition)
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13 pages, 3943 KiB  
Article
Towards the Mass Production of Molecularly Imprinted Polymers via Cost-Effective Photopolymerization Synthesis and Colorimetric Detection via Smartphone
by Kawtar Saidi, Dounia Elfadil and Aziz Amine
Chemosensors 2024, 12(11), 232; https://doi.org/10.3390/chemosensors12110232 - 7 Nov 2024
Viewed by 777
Abstract
The need for rapid, on-site contaminant detection is becoming increasingly vital for tackling environmental and public health challenges. This study introduces an efficient method for detecting sulfamethoxazole (SMX), a widely used antibiotic with significant environmental implications. A cost-effective, scalable approach was developed using [...] Read more.
The need for rapid, on-site contaminant detection is becoming increasingly vital for tackling environmental and public health challenges. This study introduces an efficient method for detecting sulfamethoxazole (SMX), a widely used antibiotic with significant environmental implications. A cost-effective, scalable approach was developed using lab-on-paper devices integrated with molecularly imprinted polymers (MIPs), synthesized through an in situ photopolymerization process that was completed in just 10 min. Using only 2 mL of MIP solution enabled the efficient mass production of 100 disks. Traditional template extraction, which often takes hours or days, was reduced to just 10 min using a multichannel micropipette and absorbent fabric. The MIP-PAD achieved a limit of detection (LOD) of 0.8 µg/mL and a limit of quantification (LOQ) of 2.4 µg/mL, with measurements obtained using a smartphone-based colorimetric detection system. It exhibited excellent repeatability, with a relative standard deviation (RSD) of 3.26% across seven tests, high reusability for up to eight cycles, and recovery rates for real samples ranging from 81.24% to 99.09%. This method provides notable improvements in sensitivity, reproducibility, and environmental sustainability over conventional techniques. The user-friendly platform integrating smartphone-based colorimetric detection is highly practical for real-time applications, offering broad potential for environmental monitoring, food safety, and healthcare. Full article
(This article belongs to the Special Issue Low-Cost Chemosenors for Applications in Environment, Health, Food, and Industry Process Control)
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16 pages, 4413 KiB  
Article
Metal–Organic Framework-Derived CeO2/Gold Nanospheres in a Highly Sensitive Electrochemical Sensor for Uric Acid Quantification in Milk
by Miloš Ognjanović, Milena Marković, Vladimír Girman, Vladimir Nikolić, Sanja Vranješ-Đurić, Dalibor M. Stanković and Branka B. Petković
Chemosensors 2024, 12(11), 231; https://doi.org/10.3390/chemosensors12110231 - 3 Nov 2024
Viewed by 1154
Abstract
In this work, CeBTC (a cerium(III) 1,3,5-benzene-tricarboxylate), was used as a precursor for obtaining CeO2 nanoparticles (nanoceria) with better sensor performances than CeO2 nanoparticles synthesized by the solvothermal method. Metal–organic framework-derived nanoceria (MOFdNC) were functionalized with spheric gold nanoparticles (AuNPs) to [...] Read more.
In this work, CeBTC (a cerium(III) 1,3,5-benzene-tricarboxylate), was used as a precursor for obtaining CeO2 nanoparticles (nanoceria) with better sensor performances than CeO2 nanoparticles synthesized by the solvothermal method. Metal–organic framework-derived nanoceria (MOFdNC) were functionalized with spheric gold nanoparticles (AuNPs) to further improve non-enzymatic electrode material for highly sensitive detection of prominent biocompound uric acid (UA) at this modified carbon paste electrode (MOFdNC/AuNPs&CPE). X-ray powder diffraction (XRPD) and transmission electron microscopy (TEM) analysis were used for morphological structure characterization of the obtained nanostructures. Cyclic voltammetry and electrochemical impedance spectroscopy, both in an [Fe(CN)6]3−/4− redox system and uric acid standard solutions, were used for the characterization of material electrocatalytic performances, the selection of optimal electrode modifier, and the estimation of nature and kinetic parameters of the electrode process. Square-wave voltammetry (SWV) was chosen, and the optimal parameters of technique and experimental conditions were established for determining uric acid over MOFdNC/AuNPs&CPE. Together with the development of the sensor, the detection procedure was optimized with the following analytical parameters: linear operating ranges of 0.05 to 1 µM and 1 to 50 µM and a detection limit of 0.011 µM, with outstanding repeatability, reproducibility, and stability of the sensor surface. Anti-interference experiments yielded a stable and nearly unchanged current response with negligible or no change in peak potential. After minor sample pretreatment, the proposed electrode was successfully applied for the quantification of UA in milk. Full article
(This article belongs to the Special Issue Chemical and Biosensors Based on Metal-Organic Frames (MOFs))
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24 pages, 5048 KiB  
Review
Humidity Sensing Using Polymers: A Critical Review of Current Technologies and Emerging Trends
by Jintian Qian, Ruiqin Tan, Mingxia Feng, Wenfeng Shen, Dawu Lv and Weijie Song
Chemosensors 2024, 12(11), 230; https://doi.org/10.3390/chemosensors12110230 - 2 Nov 2024
Viewed by 3205
Abstract
In the post-pandemic era, human demand for a healthy lifestyle and a smart society has surged, leading to vibrant growth in the field of flexible electronic sensor technology for health monitoring. Flexible polymer humidity sensors are not only capable of the real-time monitoring [...] Read more.
In the post-pandemic era, human demand for a healthy lifestyle and a smart society has surged, leading to vibrant growth in the field of flexible electronic sensor technology for health monitoring. Flexible polymer humidity sensors are not only capable of the real-time monitoring of human respiration and skin moisture information but also serve as a non-contact human–machine interaction method. In addition, the development of moist-electric generation technology is expected to break free from the traditional reliance of flexible electronic devices on power equipment, which is of significant importance for the miniaturization, reliability, and environmentally friendly development of flexible devices. Currently, flexible polymer humidity sensors are playing a significant role in the field of wearable electronic devices and thus have attracted considerable attention. This review begins by introducing the structural types and working principles of various humidity sensors, including the types of capacitive, impedance/resistive, frequency-based, fiber optic, and voltage-based sensors. It mainly focuses on the latest research advancements in flexible polymer humidity sensors, particularly in the modification of humidity-sensitive materials, sensor fabrication, and hygrosensitivity mechanisms. Studies on material composites including different types of polymers, polymers combined with porous nanostructured materials, polymers combined with metal oxides, and two-dimensional materials are reviewed, along with a comparative summary of the fabrication and performance mechanisms of related devices. This paper concludes with a discussion on the current challenges and opportunities faced by flexible polymer humidity sensors, providing new research perspectives for their future development. Full article
(This article belongs to the Special Issue Feature Review Papers in Chemical/Bio-Sensors and Analytical Chemistry in 2024)
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33 pages, 6915 KiB  
Review
Conventional and Emerging Diagnostic Approaches for Differentiated Thyroid Carcinoma
by Kathelina Kristollari, Abraham Abbey Paul, Sagi Angel and Robert S. Marks
Chemosensors 2024, 12(11), 229; https://doi.org/10.3390/chemosensors12110229 - 1 Nov 2024
Viewed by 1710
Abstract
Differentiated thyroid carcinoma (DTC) is among the most prevalent endocrine cancers. The diagnosis of DTC has witnessed tremendous progress in terms of technological advancement and clinical operational guidelines. DTC diagnostics have evolved significantly over centuries, from early clinical examinations to modern molecular testing [...] Read more.
Differentiated thyroid carcinoma (DTC) is among the most prevalent endocrine cancers. The diagnosis of DTC has witnessed tremendous progress in terms of technological advancement and clinical operational guidelines. DTC diagnostics have evolved significantly over centuries, from early clinical examinations to modern molecular testing and imaging modalities. The diagnosis and management of DTC are currently dependent on the international histological classification and identification of specific genetic abnormalities in tumor tissue, as well as the prognostic implications that can inform treatment decisions. This study goes down the memory lanes of various diagnostic methods for DTCs, highlighting recent advancements in molecular testing and point-of-care (POC) technology. Beginning with conventional methods like fine needle aspiration biopsy (FNAB), fine needle aspiration cytology (FNAC), and ultrasound (US) and moving to contemporary innovative approaches such as POC-thyroglobulin (POC-Tg) and liquid biopsy, this review showcases the current trends in DTC diagnostics. Although considerable progress has been achieved in early malignancy detection, patient stratification, prognosis, and personalized treatment, there is a need to refine the mainstay diagnostic procedures. Finally, future perspectives were provided, and emerging roles of artificial intelligence in DTC diagnostics were explored. Full article
(This article belongs to the Special Issue Rapid Point-of-Care Testing Technology and Application)
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32 pages, 9468 KiB  
Article
Assessing Data Fusion in Sensory Devices for Enhanced Prostate Cancer Detection Accuracy
by Jeniffer Katerine Carrillo Gómez, Carlos Alberto Cuastumal Vásquez, Cristhian Manuel Durán Acevedo and Jesús Brezmes Llecha
Chemosensors 2024, 12(11), 228; https://doi.org/10.3390/chemosensors12110228 - 1 Nov 2024
Viewed by 873
Abstract
The combination of an electronic nose and an electronic tongue represents a significant advance in the pursuit of effective detection methods for prostate cancer, a widespread form of cancer affecting men across the globe. These cutting-edge devices, collectively called “E-Senses”, use data fusion [...] Read more.
The combination of an electronic nose and an electronic tongue represents a significant advance in the pursuit of effective detection methods for prostate cancer, a widespread form of cancer affecting men across the globe. These cutting-edge devices, collectively called “E-Senses”, use data fusion to identify distinct chemical compounds in exhaled breath and urine samples, potentially improving existing diagnostic techniques. This study combined the information from two sensory perception devices to detect prostate cancer in biological samples (breath and urine). To achieve this, data from patients diagnosed with the disease and from control individuals were collected using a gas sensor array and chemical electrodes. The signals were subjected to data preprocessing algorithms to prepare them for analysis. Following this, the datasets for each device were individually analyzed and subsequently merged to enhance the classification results. The data fusion was assessed and it successfully improved the accuracy of detecting prostate-related conditions and distinguishing healthy patients, achieving the highest success rate possible (100%) in classification through machine learning methods, outperforming the results obtained from individual electronic devices. Full article
(This article belongs to the Special Issue Advanced Sensing Technology for Biomarker Detection and Medical Diagnosis)
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12 pages, 816 KiB  
Article
Analysis of Solid Formulates Using UV-Visible Diffused Reflectance Spectroscopy with Multivariate Data Processing Based on Net Analyte Signal and Standard Additions Method
by Nicholas Kassouf, Alessandro Zappi, Michela Monticelli and Dora Melucci
Chemosensors 2024, 12(11), 227; https://doi.org/10.3390/chemosensors12110227 - 1 Nov 2024
Viewed by 1164
Abstract
Quality control in pharmaceutical manufacturing necessitates rigorous testing and approval, adhering to Current Good Manufacturing Practices before commercialization. The production of solid drugs presents significant industrial challenges regarding uniformity, homogeneity, and consistency. Traditional quality guidelines rely on classical analytical methods such as liquid [...] Read more.
Quality control in pharmaceutical manufacturing necessitates rigorous testing and approval, adhering to Current Good Manufacturing Practices before commercialization. The production of solid drugs presents significant industrial challenges regarding uniformity, homogeneity, and consistency. Traditional quality guidelines rely on classical analytical methods such as liquid chromatography coupled with mass spectrometry. However, the emergence of Process Analytical Technology introduced non-destructive, rapid, and cost-effective methods like UV-Visible Diffuse Reflectance Spectroscopy. The present study aimed to develop a chemometric method for quantifying Active Pharmaceutical Ingredients (APIs) in Neo Nisidine®, a solid mixture drug, using spectrophotometric data. The Net Analyte Signal (NAS) method, combined with standard additions, allowed the creation of a pseudo-univariate standard addition model, overcoming some challenges in solid-phase analysis. Successful quantifications of APIs in ideal laboratory samples and real pharmaceutical tablets were obtained. NAS-based chemometric models showed high precision and reliability, whose results were validated by comparisons with HPLC ones. The study revealed that solid-phase spectrophotometric analyses can be considered a valid alternative to API analyses. Solid-phase analysis offers non-destructive, cost-effective, and environmentally friendly benefits, enabling its integration into pharmaceutical production to improve quality control. Full article
(This article belongs to the Special Issue Feature Papers in the Section "Analytical Methods, Instrumentation and Miniaturization")
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14 pages, 7267 KiB  
Article
Fluorescent Carbon Dots with Red Emission: A Selective Sensor for Fe(III) Ion Detection
by Ángela Fernández-Merino, Miriam Chávez, Guadalupe Sánchez-Obrero, Rafael Madueño, Manuel Blázquez, Rafael Del Caño and Teresa Pineda
Chemosensors 2024, 12(11), 226; https://doi.org/10.3390/chemosensors12110226 - 30 Oct 2024
Viewed by 1009
Abstract
We present a procedure for the synthesis and purification of p-phenylenediamine-based carbon dots that can be used for the recognition of Fe(III) ions. Carbon dots have an approximately spherical shape with an average size of 10 nm and are composed of a carbonaceous [...] Read more.
We present a procedure for the synthesis and purification of p-phenylenediamine-based carbon dots that can be used for the recognition of Fe(III) ions. Carbon dots have an approximately spherical shape with an average size of 10 nm and are composed of a carbonaceous core surrounded by functional groups attached to it, both of which are responsible for their dual fluorescence properties. The emission bands have a different behavior, with a blue band dependent and a red emission independent of the excitation wavelength, respectively. Red emission is appropriate for the detection of ions and other molecules in biological environments because this high wavelength prevents the occurrence of processes such as resonance energy transfer and internal filter effects. In particular, the presence of Fe(III) ions produces an important quenching phenomenon that can be applied to the fabrication of a sensor. The platform is very sensitive, with a detection limit of 0.85 µM, which is within the lowest values reported for this ion, and a high selectivity that is believed to be due to the formation of a specific complex in the ground state through specific interactions of Fe (III) ions with pyridinic and amino groups on the surface of the nanomaterials. Full article
(This article belongs to the Special Issue Colorimetric and Fluorescent Sensors: Current Status and Future Development)
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14 pages, 2089 KiB  
Article
A Fast and Cost-Effective Electronic Nose Model for Methanol Detection Using Ensemble Learning
by Bilge Han Tozlu
Chemosensors 2024, 12(11), 225; https://doi.org/10.3390/chemosensors12110225 - 29 Oct 2024
Viewed by 842
Abstract
Methanol, commonly used to cut costs in the production of counterfeit alcohol, is extremely harmful to human health, potentially leading to severe outcomes, including death. In this study, an electronic nose system was designed using 11 inexpensive gas sensors to detect the proportion [...] Read more.
Methanol, commonly used to cut costs in the production of counterfeit alcohol, is extremely harmful to human health, potentially leading to severe outcomes, including death. In this study, an electronic nose system was designed using 11 inexpensive gas sensors to detect the proportion of methanol in an alcohol mixture. A total of 168 odor samples were taken and analyzed from eight types of ethanol–methanol mixtures prepared at different concentrations. Only 4 features out of 264 were selected using the feature selection method based on feature importance. These four features were extracted from the data of MQ-3, MQ-4, and MQ-137 sensors, and the classification process was carried out using the data of these sensors. A Voting Classifier, an ensemble model, was used with Linear Discriminant Analysis, Support Vector Machines, and Extra Trees algorithms. The Voting Classifier achieved 85.88% classification accuracy before and 81.85% after feature selection. With its cost effectiveness, fast processing time, and practicality, the recommended system shows great potential for detecting methanol, which threatens human health in counterfeit drink production. Full article
(This article belongs to the Special Issue Gas Sensors and Electronic Noses for the Real Condition Sensing)
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16 pages, 2843 KiB  
Article
A Reaction-Based Approach to Colorimetric Detection of Organic Analytes in Water Using a Chlorine-Containing Carbocyanine Dye and Hypochlorite
by Anna V. Shik, Evgenii V. Skorobogatov, Ramil M. Akhmetov, Irina A. Doroshenko, Tatyana A. Podrugina, Gleb K. Sugakov and Mikhail K. Beklemishev
Chemosensors 2024, 12(11), 224; https://doi.org/10.3390/chemosensors12110224 - 27 Oct 2024
Viewed by 821
Abstract
Water quality control employs techniques mostly targeting individual analytes; group detection is also practiced, but the choice of group methods is limited, which supports interest in developing such methods. We have examined the interaction of hypochlorite with a chlorine-containing heptamethine carbocyanine dye in [...] Read more.
Water quality control employs techniques mostly targeting individual analytes; group detection is also practiced, but the choice of group methods is limited, which supports interest in developing such methods. We have examined the interaction of hypochlorite with a chlorine-containing heptamethine carbocyanine dye in the presence of 30 organic and inorganic model analytes that were found to induce diverse color changes in the system. The main supposed mechanisms are retardation of the dye oxidation with hypochlorite (presumably by scavenging chlorine radicals) and substitution of chlorine atom in the dye by the most nucleophilic analytes (amines, amino acids, proteins, DNA, phenol). The grass-green substitution product is more contrastingly visible against the dark-purple hypochlorite oxidation product of the dye than against the original emerald-green dye. The indicator reaction is monitored photographically for 10–40 min and the images are processed using principal component analysis (PCA) or linear discriminant analysis (LDA), allowing for data convolution for the complex color transitions. Nitrogen compounds are discriminated from the others, and more reactive analytes (tryptophan, cysteine, bovine serum albumin, and DNA) are detected in the presence of less reactive ones in natural water. The system is promising for the development of group assays for dissolved organic matter and the discrimination of water samples. Full article
(This article belongs to the Special Issue Low-Cost Chemosenors for Applications in Environment, Health, Food, and Industry Process Control)
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11 pages, 2666 KiB  
Article
Increased Autonomous Bioluminescence Emission from Mammalian Cells by Enhanced Cofactor Synthesis
by Theresa Brinker and Carola Gregor
Chemosensors 2024, 12(11), 223; https://doi.org/10.3390/chemosensors12110223 - 25 Oct 2024
Viewed by 670
Abstract
The bacterial bioluminescence system has been successfully implemented in mammalian cell lines, enabling the substrate-free luminescence imaging of living cells. One of the major limitations of the system is its comparatively low brightness. To improve light emission, we aimed to increase the cellular [...] Read more.
The bacterial bioluminescence system has been successfully implemented in mammalian cell lines, enabling the substrate-free luminescence imaging of living cells. One of the major limitations of the system is its comparatively low brightness. To improve light emission, we aimed to increase the cellular production of FMNH2 and NADPH, which serve as cosubstrates in the bacterial bioluminescence reaction. We coexpressed different proteins involved in the synthesis of these two cofactors together with the proteins of the bacterial bioluminescence system in different mammalian cell lines. The combined expression of a riboflavin kinase (RFK) and a constitutively active Akt2 variant (Akt2CA) that participate in the cellular production of FMN and NADP+, respectively, increased bioluminescence emission up to 2.4-fold. The improved brightness allows autonomous bioluminescence imaging of mammalian cells at a higher signal-to-noise ratio and enhanced spatiotemporal resolution. Full article
(This article belongs to the Special Issue Chemiluminescent and Bioluminescent Sensors)
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16 pages, 5590 KiB  
Article
Coral-like Ti3C2Tx/PANI Binary Nanocomposite Wearable Enzyme Electrochemical Biosensor for Continuous Monitoring of Human Sweat Glucose
by Jinhao Wang, Lijuan Chen, Fan Chen, Xinyang Lu, Xuanye Li, Yu Bao, Wei Wang, Dongxue Han and Li Niu
Chemosensors 2024, 12(11), 222; https://doi.org/10.3390/chemosensors12110222 - 25 Oct 2024
Viewed by 943
Abstract
With the continuous advancement of contemporary medical technology, an increasing number of individuals are inclined towards self-monitoring their physiological health information, specifically focusing on monitoring blood glucose levels. However, as an emerging flexible sensing technique, continuous and non-invasive monitoring of glucose in sweat [...] Read more.
With the continuous advancement of contemporary medical technology, an increasing number of individuals are inclined towards self-monitoring their physiological health information, specifically focusing on monitoring blood glucose levels. However, as an emerging flexible sensing technique, continuous and non-invasive monitoring of glucose in sweat offers a promising alternative to conventional invasive blood tests for measuring blood glucose levels, reducing the risk of infection associated with blood testing. In this study, we fabricated a flexible and wearable electrochemical enzyme sensor based on a two-dimensional Ti3C2Tx MXene nanosheets and coral-like polyaniline (PANI) binary nanocomposite (denoted as Ti3C2Tx/PANI) for continuous, non-invasive, real-time monitoring of sweat glucose. The exceptional conductivity of Ti3C2Tx MXene nanosheets, in conjunction with the mutual doping effect facilitated by coral-like PANI, significantly enhances electrical conductivity and specific surface areas of Ti3C2Tx/PANI. Consequently, the fabricated sensor exhibits remarkable sensitivity (25.16 μA·mM−1·cm−2), a low detection limit of glucose (26 μM), and an extensive detection range (0.05 mM ~ 1.0 mM) in sweat. Due to the dense coral-like structure of Ti3C2Tx/PANI binary nanocomposite, a larger effective area is obtained to offer more active sites for enzyme immobilization and enhancing enzymatic catalytic activity. Moreover, the sensor demonstrates exceptional mechanical performance, enabling a 60° bend in practical applications, thus satisfying the rigorous demands of human sweat detection applications. The results obtained from continuous 60 min in vitro monitoring of sweat glucose levels demonstrate a robust correlation with the data of blood glucose levels collected by a commercial glucose meter. Furthermore, the fabricated Ti3C2Tx/PANI/GOx sensor demonstrated agreement with HPLC findings regarding the actual concentration of added glucose. This study presents an efficient and practical approach for the development of a highly reliable MXene glucose biosensor, enabling stable and long-term monitoring of glucose levels in human sweat. Full article
(This article belongs to the Special Issue Dedicated to Professor Huangxian Ju and Professor Xueji Zhang on the Occasion of Their 60th Birthday for Their Outstanding Contributions to the Field of Chemical/Bio Sensors)
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