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Chemosensors, Volume 11, Issue 9 (September 2023) – 42 articles

Cover Story (view full-size image): Single-atom nanomaterials (SANs) with high atom utilization efficiency and homogenous active sites have been utilized for the construction of electrochemical sensors, which are favorable for improving the sensitivity and selectivity of detection. In this review, we first describe the characteristics and advantages of SANs. Strategies to improve the performance of sensors by modulating the active centers, including metal atoms and their coordination environments, of noble metal-based and non-noble metal-based SANs are then presented. Subsequently, the construction of electrochemical, electrochemiluminescent and photoelectrochemical sensors based on SANs and their applications in biochemical and environmental analysis are summarized. Finally, the potential and challenges of SANs for electrochemical sensing applications are outlined. View this paper
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15 pages, 5671 KiB  
Article
Surface Enhanced Raman Spectroscopy Pb2+ Ion Detection Based on a Gradient Boosting Decision Tree Algorithm
by Minghao Wang and Jing Zhang
Chemosensors 2023, 11(9), 509; https://doi.org/10.3390/chemosensors11090509 - 21 Sep 2023
Viewed by 1141
Abstract
Lead pollution poses a serious threat to the natural environment, and a fast and high-sensitivity method is urgently needed. SERS can be used for the detection of Pb2+ ions, which is urgently needed. Based on the SERS spectral reference data set of [...] Read more.
Lead pollution poses a serious threat to the natural environment, and a fast and high-sensitivity method is urgently needed. SERS can be used for the detection of Pb2+ ions, which is urgently needed. Based on the SERS spectral reference data set of lead nitride (Pb(NO3)2), a model for detecting Pb2+ was established by using a traditional machine learning algorithm and the GBDT algorithm. Principal component analysis was used to compare the batch effect reduction in different pretreatment methods in order to find the optimal combination of such methods and machine learning models. The combination of LightGBM algorithms successfully identified Pb2+ from cross-batch data, exceeding the 84.6% balanced accuracy of the baseline correction+ radial basis function kernel support vector machine (BC+RBFSVM) model and showing satisfactory results, with a 91.4% balanced accuracy and a 0.9313 area under the ROC curve. Full article
(This article belongs to the Special Issue Application of Luminescent Materials for Sensing)
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22 pages, 9466 KiB  
Review
Design of DNA-Based Artificial Transmembrane Channels for Biosensing and Biomedical Applications
by Wanyu Xu, Hui Chen, Yang Li, Shuangna Liu, Kemin Wang and Jianbo Liu
Chemosensors 2023, 11(9), 508; https://doi.org/10.3390/chemosensors11090508 - 18 Sep 2023
Viewed by 1579
Abstract
Biomolecular channels on the cell membrane are essential for transporting substances across the membrane to maintain cell physiological activity. Artificial transmembrane channels used to mimic biological membrane channels can regulate intra/extracellular ionic and molecular homeostasis, and they elucidate cellular structures and functionalities. Due [...] Read more.
Biomolecular channels on the cell membrane are essential for transporting substances across the membrane to maintain cell physiological activity. Artificial transmembrane channels used to mimic biological membrane channels can regulate intra/extracellular ionic and molecular homeostasis, and they elucidate cellular structures and functionalities. Due to their program design, facile preparation, and high biocompatibility, DNA nanostructures have been widely used as scaffolds for the design of artificial transmembrane channels and exploited for ionic and molecular transport and biomedical applications. DNA-based artificial channels can be designed from two structural modules: DNA nanotubes/nanopores as transport modules for mass transportation and hydrophobic segments as anchor modules for membrane immobilization. In this review, various lipophilic modification strategies for the design of DNA channels and membrane insertion are outlined. Several types of DNA transmembrane channels are systematically summarized, including DNA wireframe channels, DNA helix bundle channels, DNA tile channels, DNA origami channels, and so on. We then discuss efforts to exploit them in biosensor and biomedical applications. For example, ligand-gated and environmental stimuli-responsive artificial transmembrane channels have been designed for transmembrane signal transduction. DNA-based artificial channels have been developed for cell mimicry and the regulation of cell behaviors. Finally, we provide some perspectives on the challenges and future developments of artificial transmembrane channel research in biomimetic science and biomedical applications. Full article
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21 pages, 5290 KiB  
Review
Electrochemical Perovskite-Based Sensors for the Detection of Relevant Biomarkers for Human Kidney Health
by Claudia Ivone Piñón-Balderrama, César Leyva-Porras, Alain Salvador Conejo-Dávila, Anayansi Estrada-Monje, María Cristina Maldonado-Orozco, Simón Yobanny Reyes-López and Erasto Armando Zaragoza-Contreras
Chemosensors 2023, 11(9), 507; https://doi.org/10.3390/chemosensors11090507 - 17 Sep 2023
Cited by 1 | Viewed by 1429
Abstract
The importance of biomarker quantification in technology cannot be overstated. It has numerous applications in medical diagnostics, drug delivery, and the timely implementation of prevention and control strategies for highly prevalent diseases worldwide. However, the discovery of new tools for detection has become [...] Read more.
The importance of biomarker quantification in technology cannot be overstated. It has numerous applications in medical diagnostics, drug delivery, and the timely implementation of prevention and control strategies for highly prevalent diseases worldwide. However, the discovery of new tools for detection has become increasingly necessary. One promising avenue is the use of perovskite-based materials, which exhibit excellent catalytic activity and redox properties. These make them ideal candidates for the development of electrochemical sensors. In this review, the advances of purely non-enzymatic electrochemical detection of bio-analytes, with ABO3 perovskite form, are presented. The work allows the visualization of some of the modifications in the composition and crystal lattice of the perovskites and some variations in the assembly of the electrodes, which can result in systems with a better response to the detection of analytes of interest. These findings have significant implications for improving the accuracy and speed of biomarker detection, ultimately benefiting patients and healthcare professionals alike. Full article
(This article belongs to the Special Issue Current Development on Electrochemical Glucose Biosensors)
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19 pages, 5003 KiB  
Article
Surface-Catalyzed Zinc Oxide Nanorods and Interconnected Tetrapods as Efficient Methane Gas Sensing Platforms
by Abbey Knoepfel, Bed Poudel and Sanju Gupta
Chemosensors 2023, 11(9), 506; https://doi.org/10.3390/chemosensors11090506 - 17 Sep 2023
Viewed by 1198
Abstract
Nanostructured metal oxide semiconductors have proven to be promising for the gas sensing domain. However, there are challenges associated with the fabrication of high-performance, low-to-room-temperature operation sensors for methane and other gases, including hydrogen sulfide, carbon dioxide, and ammonia. The functional properties of [...] Read more.
Nanostructured metal oxide semiconductors have proven to be promising for the gas sensing domain. However, there are challenges associated with the fabrication of high-performance, low-to-room-temperature operation sensors for methane and other gases, including hydrogen sulfide, carbon dioxide, and ammonia. The functional properties of these semiconducting oxides can be improved by altering the morphology, crystal size, shape, and topology. Zinc oxide (ZnO) is an attractive option for gas sensing, but the need for elevated operating temperatures has limited its practical use as a commercial gas sensor. In this work, we prepared ZnO nanorod (ZnO-NR) arrays and interconnected tetrapod ZnO (T-ZnO) network sensing platforms as chemiresistive methane sensors on silicon substrates with platinum interdigitated electrodes and systematically characterized their methane sensing response in addition to their structural and physical properties. We also conducted surface modification by photochemical-catalyzed palladium, Pd, and Pd-Ag alloy nanoparticles and compared the uniformly distributed Pd decoration versus arrayed dots. The sensing performance was assessed in terms of target gas response magnitude (RM) and response percentage (R) recorded by changes in electrical resistance upon exposure to varying methane concentration (100–10,000 ppm) under thermal (operating temperatures = 175, 200, 230 °C) and optical (UV A, 365 nm illumination) excitations alongside response/recovery times, and limit of detection quantification. Thin film sensing platforms based on T-ZnO exhibited the highest response at 200 °C (RM = 2.98; R = 66.4%) compared to ZnO-NR thin films at 230 °C (RM = 1.34; R = 25.5%), attributed to the interconnected network and effective bandgap and barrier height reduction of the T-ZnO. The Pd-Ag-catalyzed and Pd dot-catalyzed T-ZnO films had the fastest response and recovery rates at 200 °C and room temperature under UV excitation, due to the localized Pd nanoparticles dots resulting in nano Schottky barrier formation, as opposed to the films coated with uniformly distributed Pd nanoparticles. The experimental findings present morphological differences, identify various mechanistic aspects, and discern chemical pathways for methane sensing. Full article
(This article belongs to the Special Issue The State-of-the-Art Gas Sensor)
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16 pages, 7762 KiB  
Article
Surface-Enhance Raman Spectroscopy Detection of Thiabendazole in Frozen Food Products: The Case of Blueberries and Their Extracts
by Csilla Müller Molnár, Camelia Berghian-Groșan, Dana Alina Măgdaș and Simona Cîntă Pînzaru
Chemosensors 2023, 11(9), 505; https://doi.org/10.3390/chemosensors11090505 - 17 Sep 2023
Cited by 1 | Viewed by 1066
Abstract
To improve the control and detection methods of thiabendazole (TBZ), a fungicide and parasiticide often used in food products, we investigated the performance of the SERS technique applied to frozen blueberry fruits available on the market. TBZ-treated fruit extracts provided a multiplexed SERS [...] Read more.
To improve the control and detection methods of thiabendazole (TBZ), a fungicide and parasiticide often used in food products, we investigated the performance of the SERS technique applied to frozen blueberry fruits available on the market. TBZ-treated fruit extracts provided a multiplexed SERS feature, where the SERS bands of TBZ could be distinctly recorded among the characteristic anthocyanidins from blueberries. Quantitative SERS of TBZ in a concentration range from 20 µM to 0.2 µM has been achieved in solutions. However, quantitative multiplexed SERS is challenging due to the gradually increasing spectral background of polyphenols from extracts, which covers the TBZ signal with increasing concentration. The strategy proposed here was to employ food bentonite to filter a substantial amount of flavonoids to allow a higher SERS signal-to-background recording and TBZ recognition. Using bentonite, the LOD for SERS analysis of blueberry extracts provided a detection limit of 0.09 µM. From the relative intensity of the specific SERS bands as a function of concentration, we estimated the detection capability of TBZ to be 0.0001 mg/kg in blueberry extracts, which is two orders of magnitude lower than the maximum allowed by current regulations. Full article
(This article belongs to the Special Issue Surface-Enhanced Raman Spectroscopy for Bioanalytics)
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28 pages, 9468 KiB  
Review
MicroRNA Biosensors for Early Detection of Hepatocellular Carcinoma
by Xiaogang Lin, Ke Wang, Chunfeng Luo, Mengjie Yang and Jayne Wu
Chemosensors 2023, 11(9), 504; https://doi.org/10.3390/chemosensors11090504 - 16 Sep 2023
Cited by 2 | Viewed by 1592
Abstract
Hepatocellular carcinoma (HCC) is the main pathological type of liver cancer. Due to its insidious onset and the lack of specific early markers, HCC is often diagnosed at an advanced stage, and the survival rate of patients with partial liver resection is low. [...] Read more.
Hepatocellular carcinoma (HCC) is the main pathological type of liver cancer. Due to its insidious onset and the lack of specific early markers, HCC is often diagnosed at an advanced stage, and the survival rate of patients with partial liver resection is low. Non-coding RNAs (ncRNAs) have emerged as valuable biomarkers for HCC detection, with microRNAs (miRNAs) being a particularly relevant class of short ncRNAs. MiRNAs play a crucial role in gene expression regulation and can serve as biomarkers for early HCC detection. However, the detection of miRNAs poses a significant challenge due to their small molecular weight and low abundance. In recent years, biosensors utilizing electrochemical, optical, and electrochemiluminescent strategies have been developed to address the need for simple, rapid, highly specific, and sensitive miRNA detection. This paper reviews the recent advances in miRNA biosensors and discusses in detail the probe types, electrode materials, sensing strategies, linear ranges, and detection limits of the sensors. These studies are expected to enable early intervention and dynamic monitoring of tumor changes in HCC patients to improve their prognosis and survival status. Full article
(This article belongs to the Special Issue Advanced Techniques for the Analysis of Protein and RNA)
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12 pages, 2868 KiB  
Communication
Detection of a Nerve Agent Simulant by a Fluorescent Sensor Array
by Rossella Santonocito, Mario Spina, Roberta Puglisi, Andrea Pappalardo, Nunzio Tuccitto and Giuseppe Trusso Sfrazzetto
Chemosensors 2023, 11(9), 503; https://doi.org/10.3390/chemosensors11090503 - 15 Sep 2023
Cited by 2 | Viewed by 1676
Abstract
Detection of nerve agents (NAs) gas in the environment through portable devices to protect people in case of emergencies still remains a challenge for scientists involved in this research field. Current detection strategies require the use of cumbersome, expensive equipment that is only [...] Read more.
Detection of nerve agents (NAs) gas in the environment through portable devices to protect people in case of emergencies still remains a challenge for scientists involved in this research field. Current detection strategies require the use of cumbersome, expensive equipment that is only accessible to specialized personnel. By contrast, emerging optical detection is one of the most promising strategies for the development of reliable, easy readout devices. However, the selectivity of the existing optical sensors needs to be improved. To overcome the lack of selectivity, the innovative strategy of the optical arrays is under evaluation due to the specific response, the ease of preparation, the portability of the equipment, and the possibility to use affordable detectors, such as smartphones, that are easily accessible to non-specialized operators. In this work, the first optical-based sensor array for the selective detection of gaseous dimethylmethylphosphonate (DMMP), a NAs simulant, is reported, employing a simple smartphone as a detector and obtaining remarkably efficient and selective detection. Full article
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16 pages, 10792 KiB  
Article
A Portable Nanoporous Gold Modified Screen-Printed Sensor for Reliable and Simultaneous Multi-Vitamins Analysis
by Xinyu Gao, Siyu Chen, Xiaolei Wang, Honglei Liu and Xia Wang
Chemosensors 2023, 11(9), 502; https://doi.org/10.3390/chemosensors11090502 - 15 Sep 2023
Viewed by 957
Abstract
Despite being present in minimal amounts, vitamin B2 (VB2), vitamin C (VC), and vitamin B6 (VB6) each play indispensable roles in human metabolisms. Given that VB2, VC, and VB6 cannot be synthesized by the human body, detections of these three vitamins both in [...] Read more.
Despite being present in minimal amounts, vitamin B2 (VB2), vitamin C (VC), and vitamin B6 (VB6) each play indispensable roles in human metabolisms. Given that VB2, VC, and VB6 cannot be synthesized by the human body, detections of these three vitamins both in fermentation liquid where vitamins are industrially manufactured and in human serum where vitamin concentrations could be clinically controlled are of significant importance. Here, a nanoporous gold (NPAu) modified screen-printed electrode (NPAu/SPE) was fabricated to detect VB2, VC, and VB6 based on NPAu’s electro-oxidation towards vitamins. Owing to the wide separation of peak potentials among VB2, VC, and VB6, the simultaneous detection of these three vitamins was achieved by the NPAu/SPE within a potential range from −0.8 V to 0.8 V. The achieved limits of detection (LOD) for VB2, VC, and VB6 were 0.46, 6.44, and 1.92 μM, with sensitivities of 68.58, 4.77, and 15.94 μA/μM, respectively. Subsequent reliability experiments suggested that the NPAu/SPE exhibited solid anti-interference capability and repeatability. Additionally, the real-sample detection of the NPAu/SPE towards VB2, VC, and VB6 was achieved both in human serum and in fermentation liquid with comparable accuracy (the recovery rates were from 89.8% to 111.7%) as high-performance liquid chromatography (HPLC). Moreover, the portable NPAu/SPE showed comparable performance in terms of the LOD and linear dynamic range when compared to glassy carbon electrodes (GCE) limited to laboratory detection. The proposed NPAu/SPE possesses various advantageous properties including portability, easy fabrication, high sensitivity, and cost-efficiency, making it a potential candidate for clinical and industrial multi-vitamins analysis. Full article
(This article belongs to the Special Issue Recent Advances in Electrode Materials for Electrochemical Sensing)
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16 pages, 6379 KiB  
Article
Temperature Modulation of MOS Sensors for Enhanced Detection of Volatile Organic Compounds
by Andrea Rescalli, Davide Marzorati, Simone Gelosa, Francesco Cellesi and Pietro Cerveri
Chemosensors 2023, 11(9), 501; https://doi.org/10.3390/chemosensors11090501 - 15 Sep 2023
Cited by 1 | Viewed by 1475
Abstract
Disease diagnosis through biological fluids, particularly exhaled breath analysis, has gained increasing importance. Volatile organic compounds (VOCs) present in exhaled breath offer diagnostic potential as they reflect altered and disease-specific metabolic pathways. While gas chromatography–mass spectrometry (GC–MS) has been traditionally used for VOCs [...] Read more.
Disease diagnosis through biological fluids, particularly exhaled breath analysis, has gained increasing importance. Volatile organic compounds (VOCs) present in exhaled breath offer diagnostic potential as they reflect altered and disease-specific metabolic pathways. While gas chromatography–mass spectrometry (GC–MS) has been traditionally used for VOCs detection, electronic noses have emerged as a promising alternative for disease screening. Metal oxide semiconductor (MOS) sensors play an essential role in these devices due to their simplicity and cost-effectiveness. However, their limited specificity and sensitivity pose challenges for accurate diagnosis at lower VOCs concentrations, typical of exhaled breath. To address specificity and sensitivity issues, temperature modulation (TM) has been proposed in this paper, introducing a custom-developed electronic nose based on multiple and heterogeneous gas sensors located within an analysis chamber. Four different TM patterns (i.e., square, sine, triangular, and a combination of square and triangular) were applied to the gas sensors to test their response to three different analytes at three distinct concentrations. Data were analyzed by extracting meaningful features from the sensor raw data, and dimensionality reduction using principal component analysis (PCA) was performed. The results demonstrated distinct clusters for each experimental condition, indicating successful discrimination of analytes and concentrations. In addition, an analysis of which set of sensors and modulation pattern yielded the best results was performed. In particular, the most promising TM pattern proved to be the square and triangular combination, with optimal discrimination accuracy between both concentrations and analytes. One specific sensor, namely, TGS2600 from Figaro USA, Inc., provided the best performance. While preliminary results highlighted the potential of TM to improve the sensitivity of gas sensors in electronic nose devices, paving the way for further advancements in the field of exhaled breath analysis. Full article
(This article belongs to the Collection Sustainable Metal Oxide Materials for Sensing Applications)
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21 pages, 360 KiB  
Review
Modern Analytical Techniques for Berry Authentication
by Celia Carrillo, Igor B. Tomasevic, Francisco J. Barba and Senem Kamiloglu
Chemosensors 2023, 11(9), 500; https://doi.org/10.3390/chemosensors11090500 - 14 Sep 2023
Cited by 1 | Viewed by 1228
Abstract
The health-related properties attributed to berries and the subsequent interest awakened within the market of functional foods mean that these small fruits may be potential targets for food fraud. In this review, studies on berry authentication through modern analytical techniques are discussed in [...] Read more.
The health-related properties attributed to berries and the subsequent interest awakened within the market of functional foods mean that these small fruits may be potential targets for food fraud. In this review, studies on berry authentication through modern analytical techniques are discussed in detail. Most of the studies reported to date are related to chemical approaches, mainly chromatographic techniques. Other chemical (NMR, NIR, and Raman spectroscopy), biomolecular, and isotopic methods have also delivered promising results in the field of berry authentication, although there is still limited information available in this respect. Despite the potential of the methods described in the present review, to date, there is no universal one. Therefore, combinations of different approaches in order to complement each other are increasingly used (e.g., HPTLC and mass spectrometry; Raman and IR spectroscopies; biomolecular and analytical techniques…). Considering that adulteration practices are increasingly evolving, continuous research in the field of food authentication is needed, especially in the case of berries, since there are still some berry species that have not yet been included in any authentication study. Full article
(This article belongs to the Special Issue GC, MS and GC-MS Analytical Methods: Opportunities and Challenges)
3 pages, 194 KiB  
Editorial
Chemosensors for Ion Detection
by Kien Wen Sun
Chemosensors 2023, 11(9), 499; https://doi.org/10.3390/chemosensors11090499 - 12 Sep 2023
Viewed by 929
Abstract
The advancement in chemosensory research towards the ionic species quantitation becomes vital to securing the environment for the future [...] Full article
(This article belongs to the Special Issue Chemosensors for Ion Detection)
17 pages, 5009 KiB  
Article
Optimization of the Geometrical Design for an All-Dielectric Metasurface Sensor with a High Refractive-Index Response
by Chia-Te Chang, Chia-Ming Yang, I-Hsuan Chen, Chih-Ching Ho, Yu-Jen Lu and Chih-Jen Yu
Chemosensors 2023, 11(9), 498; https://doi.org/10.3390/chemosensors11090498 - 11 Sep 2023
Viewed by 1232
Abstract
This study aims to develop a refractive-index sensor operating in the visible region using an all-dielectric metasurface, which was chosen for its advantages of low optical loss and narrow spectral bandwidth, compared to those of conventional metallic metasurfaces. COMSOL software was utilized as [...] Read more.
This study aims to develop a refractive-index sensor operating in the visible region using an all-dielectric metasurface, which was chosen for its advantages of low optical loss and narrow spectral bandwidth, compared to those of conventional metallic metasurfaces. COMSOL software was utilized as a calculation tool to simulate the resonant properties of an all-dielectric metasurface composed of a circular nanohole-structured titanium oxide (TiO2) thin film, with the aim of enhancing the sensitivity of the refractive index for sensing targets. The simulation focused on finding the best geometrical conditions for the all-dielectric metasurface to achieve high sensitivity. Two resonance modes observed in this metasurface were considered: the quasi-bound-state-in-the-continuum (qBIC) mode and the perfect-reflection (PR) mode. The simulated results demonstrated that high sensitivities of 257 nm/RIU at the PR mode and 94 nm/RIU at the qBIC mode in the visible spectral range could be obtained by periodically constructing the metasurface with a unit cell having a lattice constant of 350 nm, a nanohole radius of 160 nm, and a nanohole depth of 250 nm. Furthermore, the study showed that the resonance mode that enabled high sensitivity was the PR mode, with a sensitivity nearly three times larger than that of the qBIC mode and the ability to reach the highest reflectance at the resonance wavelength. The optimized feature had the highest reflectance at a resonant wavelength of 570.19 nm, and although the quality factor was 25.50, these designed parameters were considered sufficient for developing a refractive index biosensor with high sensitivity and optical efficiency when operating in the visible spectral range. Full article
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23 pages, 2755 KiB  
Review
Chemical Sensing and Analysis with Optical Nanostructures
by Chenyu Dong, Yifan Wang, Xiaoyan Zhao, Jie Bian and Weihua Zhang
Chemosensors 2023, 11(9), 497; https://doi.org/10.3390/chemosensors11090497 - 9 Sep 2023
Viewed by 1224
Abstract
Nanostructures and nanomaterials, especially plasmonic nanostructures, often show optical properties that conventional materials lack and can manipulate light, as well as various light–matter interactions, in both their near-field and far-field regions with a high efficiency. Thanks to these unique properties, not only can [...] Read more.
Nanostructures and nanomaterials, especially plasmonic nanostructures, often show optical properties that conventional materials lack and can manipulate light, as well as various light–matter interactions, in both their near-field and far-field regions with a high efficiency. Thanks to these unique properties, not only can they be used to enhance the sensitivity of chemical sensing and analysis techniques, but they also provide a solution for designing new sensing devices and simplifying the design of analytical instruments. The earliest applications of optical nanostructures are surface-enhanced spectroscopies. With the help of the resonance field enhancement of plasmonic nanostructures, molecular signals, such as Raman, infrared absorption, and fluorescence can be significantly enhanced, and even single-molecule analysis can be realized. Moreover, the resonant field enhancements of plasmonic nanostructures are often associated with other effects, such as optical forces, resonance shifts, and photothermal effects. Using these properties, label-free plasmonic sensors, nano-optical tweezers, and plasmonic matrix-assisted laser desorption/ionization have also been demonstrated in the past two decades. In the last few years, the research on optical nanostructures has gradually expanded to non-periodic 2D array structures, namely metasurfaces. With the help of metasurfaces, light can be arbitrarily manipulated, leading to many new possibilities for developing miniaturized integrated intelligent sensing and analysis systems. In this review, we discuss the applications of optical nanostructures in chemical sensing and analysis from both theoretical and practical aspects, aiming at a concise and unified framework for this field. Full article
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19 pages, 2523 KiB  
Article
Development of an Online Instrument for Continuous Gaseous PAH Quantification: Laboratory Evaluation and Comparison with The Offline Reference UHPLC-Fluorescence Method
by Joana Vaz-Ramos, Mathilde Mascles, Anaïs Becker, Damien Bourgain, Audrey Grandjean, Sylvie Bégin-Colin, Franck Amiet, Damien Bazin and Stéphane Le Calvé
Chemosensors 2023, 11(9), 496; https://doi.org/10.3390/chemosensors11090496 - 9 Sep 2023
Viewed by 1003
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants formed during incomplete combustion or pyrolysis of organic material. The reliable quantification of PAH in airborne samples is still difficult, costly, and time-consuming due to the use of offline techniques, including long sampling on filters/adsorbents, [...] Read more.
Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants formed during incomplete combustion or pyrolysis of organic material. The reliable quantification of PAH in airborne samples is still difficult, costly, and time-consuming due to the use of offline techniques, including long sampling on filters/adsorbents, laboratory extraction, purification, and concentration steps before analysis. To tackle these drawbacks, this work focused on the development of a fully automatic gas chromatograph (GC) equipped with a flame ionization detector (FID) and a sample preconcentration unit (PC) for gas sampling. This instrument was validated under laboratory-controlled conditions in the range 0–10 ng for 18 PAH. The chromatographic separation was rather satisfactory except for two PAH pairs, which were quantified together. For all compounds, the peak areas increased perfectly with the gaseous PAH concentration (R2 > 0.98), without any significant memory effect between two consecutive analyses. Considering a gaseous sample volume of 1 L, the extrapolated limits of detections (LOD) were in the range 19.9–62.6 ng/m3, depending on the PAH. Its analytical performances were then compared to those of the offline reference UHPLC-fluorescence method, widely used for airborne PAH monitoring. This was also compared with the very few portable or continuously operating instruments. Full article
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21 pages, 12863 KiB  
Article
Gas Sensing Properties of CuWO4@WO3 n-n Heterojunction Prepared by Direct Hydrolysis of Mesitylcopper (I) on WO3·2H2O Nanoleaves
by Justyna Jońca, Kevin Castello-Lux, Katia Fajerwerg, Myrtil L. Kahn, Vincent Collière, Philippe Menini, Izabela Sówka and Pierre Fau
Chemosensors 2023, 11(9), 495; https://doi.org/10.3390/chemosensors11090495 - 9 Sep 2023
Viewed by 1095
Abstract
The nanometer size Cu2O@WO3·H2O composite material has been prepared by the direct hydrolysis of mesitylcopper (I) on WO3·2H2O nanoleaves. The synthesis has been performed in toluene without the addition of any ancillary ligands. [...] Read more.
The nanometer size Cu2O@WO3·H2O composite material has been prepared by the direct hydrolysis of mesitylcopper (I) on WO3·2H2O nanoleaves. The synthesis has been performed in toluene without the addition of any ancillary ligands. The prepared nanocomposite has been deposited as a gas-sensitive layer on miniaturized silicon devices and heated up gradually to 500 °C in the ambient air. During the heating, the CuWO4 phase is formed upon the reaction of Cu2O with the WO3 support as revealed by the XRD analyses. The as-prepared CuWO4@WO3 sensors have been exposed to 10 ppm of CO or 0.4 ppm of NO2 (RH = 50%). At the operating temperature of 445 °C, a normalized response of 620% towards NO2 is obtained whereas the response to CO is significantly lower (S = 30%). Under these conditions, the sensors prepared either with pristine CuO or WO3 nanostructures are sensitive to only one of the two investigated gases, i.e., CO and NO2, respectively. Interestingly, when the CuWO4@WO3 sensitive layer is exposed to UV light emitted from a 365 nm Schottky diode, its sensitivity towards CO vanishes whereas the response towards NO2 remains high. Thus, the application of UV illumination allowed us to modify the selectivity of the device. This new nanocomposite sensor is a versatile sensitive layer that will be integrated into a gas sensor array dedicated to electronic nose platforms. Full article
(This article belongs to the Special Issue Recent Advances in Metal Oxide-Based Gas Sensors)
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1 pages, 159 KiB  
Correction
Correction: Dalapati et al. A Dual Fluorometric and Colorimetric Sulfide Sensor Based on Coordinating Self-Assembled Nanorods: Applicable for Monitoring Meat Spoilage. Chemosensors 2022, 10, 500
by Rana Dalapati, Matthew Hunter and Ling Zang
Chemosensors 2023, 11(9), 494; https://doi.org/10.3390/chemosensors11090494 - 6 Sep 2023
Viewed by 666
Abstract
There was an error in the original publication [...] Full article
24 pages, 933 KiB  
Review
Recent Trends in Biosensors for Quinolone Detection: A Comprehensive Review
by Fabian Thurner and Fatima AlZahra’a Alatraktchi
Chemosensors 2023, 11(9), 493; https://doi.org/10.3390/chemosensors11090493 - 6 Sep 2023
Cited by 1 | Viewed by 1808
Abstract
Quinolones represent a vast family of antibiotics used extensively around the globe in human and veterinary medicine. Over the past decade, the field of biosensors for quinolone detection has experienced significant growth, thanks to the advancements in nanotechnology. These biosensors have emerged as [...] Read more.
Quinolones represent a vast family of antibiotics used extensively around the globe in human and veterinary medicine. Over the past decade, the field of biosensors for quinolone detection has experienced significant growth, thanks to the advancements in nanotechnology. These biosensors have emerged as a promising tool for fast and accurate point-of-care detection of quinolones. Although research efforts have proven that it is possible to detect quinolones in complex matrices and in relevant concentration ranges, the complexity of the sensor functionalization and the risk of limited reproducibility has hindered the transfer to real-life applications. This review holistically summarizes existing electrochemical quinolone sensors in comparison to optical and piezoelectric sensors and discusses the challenges that remain to be solved. Full article
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15 pages, 3538 KiB  
Article
Development of a New HiBiT Biosensor Monitoring Stability of YAP/TAZ Proteins in Cells
by Liqing Wu, Anni Ge, Yawei Hao and Xiaolong Yang
Chemosensors 2023, 11(9), 492; https://doi.org/10.3390/chemosensors11090492 - 6 Sep 2023
Cited by 2 | Viewed by 1467
Abstract
The Hippo signaling cascade is frequently dysregulated in a variety of cancers, such as breast cancer (BC), which is one of the most commonly diagnosed malignancies in women. Among BC subtypes, triple-negative BC (TNBC) stands out due to its poor prognosis and high [...] Read more.
The Hippo signaling cascade is frequently dysregulated in a variety of cancers, such as breast cancer (BC), which is one of the most commonly diagnosed malignancies in women. Among BC subtypes, triple-negative BC (TNBC) stands out due to its poor prognosis and high metastatic potential. Despite extensive research aimed at establishing treatment options, existing therapies demonstrate limited efficacy for TNBC. Recently, it has been recognized that targeting the core components of the Hippo pathway (YAP and its paralog TAZ) is a promising strategy for developing anti-cancer treatment. However, no YAP/TAZ inhibitors have been approved by the FDA as anti-TNBC treatments, and only a few compounds have been identified that directly affect YAP and TAZ activity and stability to enhance the prospect of innovative HiBiT biosensors for monitoring of YAP and TAZ in cells. Employing these biosensors, we conducted a small-scale drug screen involving 279 compounds, leading to the identification of several small molecule inhibitors (SMIs) capable of inducing YAP/TAZ degradation in diverse TNBC cell lines. It is worth noting that some drugs may indirectly affect the protein stability following prolonged treatment, and a shorter exposure can be included in the future to identify drug candidates with more direct effects. Nevertheless, our study introduces a novel approach for assessing YAP and TAZ levels, which can have significant implications for developing anti-TNBC targeted therapies. Full article
(This article belongs to the Special Issue Advanced Techniques for the Analysis of Protein and RNA)
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12 pages, 2159 KiB  
Article
Acrylamide–Fat Correlation in Californian-Style Black Olives Using Near-Infrared Spectroscopy
by Antonio Fernández, Ismael Montero-Fernández, Olga Monago-Maraña, Elísabet Martín-Tornero and Daniel Martín-Vertedor
Chemosensors 2023, 11(9), 491; https://doi.org/10.3390/chemosensors11090491 - 6 Sep 2023
Cited by 2 | Viewed by 1105
Abstract
Californian-style is one of the most important black table olive elaborations. During its processing, table olives produce acrylamide, a potential carcinogen compound generated during sterilization. In the present study, total fat and acrylamide content in Californian-style table olives were determined and a regression [...] Read more.
Californian-style is one of the most important black table olive elaborations. During its processing, table olives produce acrylamide, a potential carcinogen compound generated during sterilization. In the present study, total fat and acrylamide content in Californian-style table olives were determined and a regression between them was performed (acrylamide concentration range: below limit of detection—2500 ng g−1 and 8–22% for total fat). Nowadays, there are fast and efficient new techniques, such as Near-Infrared Spectroscopy (NIRS) to measure fat content parameters. In that sense, NIRS was used to perform a fat content quantification model in olives in order to indirectly determine acrylamide content. Calibration models for fat quantification were obtained in defatted olive pastes from a unique variety and for olive pastes from different varieties. In the first case, best results were obtained since only one variety was used (R2 = 0.9694; RMSECV = 1.31%; and REP = 8.4%). However, in the second case, results were still acceptable R2 = 0.678, RMSECV = 2.3%, REP = 17.7% and RMSEV = 2.17%. Regression coefficients showed the most influence variables corresponded with fat. The determination coefficient for the fat and acrylamide correlation was high (r = 0.877), being an efficient approach to find out the contribution of fat degradation to acrylamide synthesis in table olives. Full article
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11 pages, 5451 KiB  
Article
Semiconductor Heterojunction-AgNPs Mediated Surface-Enhanced Raman Spectroscopy (SERS) Sensor for Portable Miniaturized Detection Platform
by Chenyu Wang, Xiaoyi Shi, Zhiyong Bao, Maofeng Zhang, Yonghui Shen and Yucheng Wu
Chemosensors 2023, 11(9), 490; https://doi.org/10.3390/chemosensors11090490 - 4 Sep 2023
Viewed by 1209
Abstract
Micro/nanoplastic pollution in the water environment has received great attention worldwide. The rapid identification and analysis of micro/nanoplastics are crucial steps for monitoring animal safety and protecting human health. Herein, we developed a novel surface-enhanced Raman spectroscopy (SERS) sensor based on Co3 [...] Read more.
Micro/nanoplastic pollution in the water environment has received great attention worldwide. The rapid identification and analysis of micro/nanoplastics are crucial steps for monitoring animal safety and protecting human health. Herein, we developed a novel surface-enhanced Raman spectroscopy (SERS) sensor based on Co3O4/Co3S4/AgNPs array substrate for the detection and analysis of micro/nanoplastics. The semiconductor heterojunction-induced charge transfer, enhanced together with the electromagnetic enhancement of plasmon AgNPs, endow the sensor with high sensitivity, thus achieving exceptional analytical and detection capability for polystyrene (PS) nanospheres of different sizes ranging from 1 µm to 1 nm. The limits of detection (LOD) for PS nanospheres (size of 1 µm and 800 nm) was as low as 25 µg/mL, even with a portable Raman spectrometer. Additionally, the periodic Co3O4/Co3S4/AgNPs array generated high repeatability of Raman signals with relative standard deviation (RSD) values less than 7.6%. As proof of this concept, we further demonstrated the simulation detection of PS in actual water samples. We measured the SERS spectra of the different sizes and concentrations of PS spiked in lake water and city water. The results showed that the sensing platform realized trace detection of PS nanospheres in lake water with a detection limit of 14 µg/mL, and a quantitative detection of PS with linear relationship (R2 = 0.962). This SERS sensor has demonstrated fast analysis of PS nanospheres, which can provide a solid basis for the qualitative and quantitative detection of various micro/nanoplastics in the real water environments. Full article
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21 pages, 12717 KiB  
Review
Emerging Luminescent Materials for Information Encryption and Anti-Counterfeiting: Stimulus-Response AIEgens and Room-Temperature Phosphorescent Materials
by Yanjie Li and Pengfei Gao
Chemosensors 2023, 11(9), 489; https://doi.org/10.3390/chemosensors11090489 - 4 Sep 2023
Viewed by 1306
Abstract
Information encryption and anti-counterfeiting play an important role in many aspects of daily life, such as in minimizing economic losses, protecting secure communication and public security, and so on. Owing to the high information capacity and ease of operation, luminescent materials for advanced [...] Read more.
Information encryption and anti-counterfeiting play an important role in many aspects of daily life, such as in minimizing economic losses, protecting secure communication and public security, and so on. Owing to the high information capacity and ease of operation, luminescent materials for advanced information encryption and anti-counterfeiting are essential to meet the increasing demand on encryption security. Herein, we summarize two emerging luminescent materials for information encryption and anti-counterfeiting—AIE materials and room-temperature phosphorescent materials. Finally, we discuss the opportunities and anticipations of these two information encryption and anti-counterfeiting materials. Full article
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22 pages, 4866 KiB  
Review
Recent Progress in Electrochemical Aptasensors: Construction and Application
by Renqiang Yuan, Jing Cai, Haojie Ma, Yi Luo, Lianhui Wang and Shao Su
Chemosensors 2023, 11(9), 488; https://doi.org/10.3390/chemosensors11090488 - 4 Sep 2023
Cited by 4 | Viewed by 2132
Abstract
Electrochemical aptasensors have gained significant attention due to their exceptional sensitivity, selectivity, stability, and rapid response, combining the advantages of electrochemical techniques with the specific recognition ability of aptamers. This review aims to provide a comprehensive summary of the recent advances in electrochemical [...] Read more.
Electrochemical aptasensors have gained significant attention due to their exceptional sensitivity, selectivity, stability, and rapid response, combining the advantages of electrochemical techniques with the specific recognition ability of aptamers. This review aims to provide a comprehensive summary of the recent advances in electrochemical aptasensors. Firstly, the construction method and the advantages of electrochemical aptasensors are introduced. Subsequently, the review highlights the application progress of electrochemical aptasensors in detecting various chemical and biological molecules, including metal ions, small biological molecules, drugs, proteins, exosomes, tumor cells, bacteria, and viruses. Lastly, the prospects and challenges associated with electrochemical aptasensors are discussed. Full article
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14 pages, 1665 KiB  
Article
Development and Validation of a Solvent-Free Headspace GC-MS Method for the Screening of Benzyl Chloride in Pharmaceutical Products
by Eunchae Song, Chanhong Min, Eunjae Kim, Sang Beom Han, Yong-Moon Lee, Kwang-Hyeon Liu, Jongki Hong and Han Bin Oh
Chemosensors 2023, 11(9), 487; https://doi.org/10.3390/chemosensors11090487 - 3 Sep 2023
Viewed by 1590
Abstract
This study presents a solvent-free headspace gas chromatography–mass spectrometry (SF-HS-GC/MS) method for robustly screening benzyl chloride, a mutagenic carcinogen, impurities in active pharmaceutical ingredients (APIs) and drug products. The SF-HS-GC/MS method simplifies analysis by eliminating solvent use, reducing matrix interference. Optimized headspace parameters [...] Read more.
This study presents a solvent-free headspace gas chromatography–mass spectrometry (SF-HS-GC/MS) method for robustly screening benzyl chloride, a mutagenic carcinogen, impurities in active pharmaceutical ingredients (APIs) and drug products. The SF-HS-GC/MS method simplifies analysis by eliminating solvent use, reducing matrix interference. Optimized headspace parameters include incubation temperature, time, and sample amount. Validation, aligned with Q2(R1) ICH guidelines and ICH M7 recommendations, covers selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, system suitability, and robustness. Employing a DB-5MS column (30 m × 0.25 mm, 0.25 µm) with solvent-free split injection, the method’s calibration curve (0.05–5 μg/g) exhibits a strong correlation (>0.9998). The LOQ was 0.1 μg/g, with precision (%CV) consistently <5% and accuracy within 95–105%. Furthermore, an investigation confirmed the absence of artefactual benzyl chloride formation in drug products under headspace conditions. The developed SF-HS-GC/MS method successfully screened benzyl chloride in cinnarizine drug substances and products. Full article
(This article belongs to the Special Issue GC, MS and GC-MS Analytical Methods: Opportunities and Challenges)
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22 pages, 4756 KiB  
Review
Single-Atom Nanomaterials in Electrochemical Sensors Applications
by Jinglin Fu and Yang Liu
Chemosensors 2023, 11(9), 486; https://doi.org/10.3390/chemosensors11090486 - 3 Sep 2023
Cited by 1 | Viewed by 1265
Abstract
In recent years, the development of highly sensitive sensors has become a popular research topic. Some functional nanomaterials occupy an important position in the sensing field by virtue of their unique structures and catalytic properties, but there are still problems such as low [...] Read more.
In recent years, the development of highly sensitive sensors has become a popular research topic. Some functional nanomaterials occupy an important position in the sensing field by virtue of their unique structures and catalytic properties, but there are still problems such as low sensitivity and poor specificity. Single-atom nanomaterials (SANs) show significant advantages in amplifying sensing signals and improving sensor interference resistance due to their high atomic utilization, structural simplicity, and homogeneity. They are expected to achieve high sensitivity and high specificity monitoring by modulating the active sites. In this review, the recent progress on SANs for electrochemical sensing applications was summarized. We first briefly summarize the features and advantages of single-atom catalysts. Then recent advances in the regulation of reaction sites in noble and non-noble metal-based SANs, including the introduction of defects in the carrier, other metal atoms, and ligand atoms, were highlighted. After that, the SANs for the construction of electrochemical, electrochemiluminescent (ECL), and photoelectrochemical (PEC) sensors and their applications in biochemical and environmental analysis were demonstrated. Finally, the future research aspect of SANs-based electrochemical sensing and the challenges of the SANs design and structure-properties revelation were illustrated, giving guidance on sensitive and accurate biosensing toward clinic diagnostic and environmental analysis. Full article
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14 pages, 3658 KiB  
Article
Enhanced Modification between Glucose Dehydrogenase and Mediator Using Epoxy Silane Assembly for Monitoring Glucose
by Tae-Won Seo, Won-Yong Jeon and Young-Bong Choi
Chemosensors 2023, 11(9), 485; https://doi.org/10.3390/chemosensors11090485 - 2 Sep 2023
Viewed by 1331
Abstract
Blood glucose monitoring (BGM) using disposable electrodes is commonly used in healthcare diagnosis. The BGM method is not suitable for people with diabetes requiring real-time monitoring who might experience sudden hypoglycemia or hyperglycemia owing to a single measurement at a specific moment. This [...] Read more.
Blood glucose monitoring (BGM) using disposable electrodes is commonly used in healthcare diagnosis. The BGM method is not suitable for people with diabetes requiring real-time monitoring who might experience sudden hypoglycemia or hyperglycemia owing to a single measurement at a specific moment. This study aimed to achieve an enhanced stability of glucose diagnosis for continuous glucose measurement systems (CGMs). A representative mediator of a second-generation glucose sensor was synthesized and coordinated with a polymer for immobilization on an indium tin oxide (ITO) electrode. For electrode immobilization, an electrode for enhanced stability was fabricated using the silanization method. The morphological properties of the electrodes were confirmed via cyclic voltammetry (CV), impedance spectroscopy, and SEM. The loss rate of the current density was only 10.11% of the initial current after 8 d. The electrode exhibited a coefficient of determination of R2 = 0.9924, sensitivity of 1.5454 μA/cm2·mM, limit of quantitation (LOQ) of 7.604 μM, and limit of detection (LOD) of 2.509 μM for glucose concentrations between 0.1 and 20.0 mM. The electrode system developed in this study is applicable to the CGM healthcare industry and is expected to be applicable to biofuel cells. Full article
(This article belongs to the Special Issue Current Development on Electrochemical Glucose Biosensors)
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14 pages, 3142 KiB  
Article
Colorimetric Detection and Killing of Bacteria by Enzyme-Instructed Self-Aggregation of Peptide-Modified Gold Nanoparticles
by Dan Yin, Xiao Li, Xin Wang, Jin-Zhou Liu, Wen-Zhi She, Jiahui Liu, Jian Ling, Rong Sheng Li and Qiue Cao
Chemosensors 2023, 11(9), 484; https://doi.org/10.3390/chemosensors11090484 - 1 Sep 2023
Viewed by 1208
Abstract
Bacterial infections seriously threaten human safety. Therefore, it is very important to develop a method for bacterial detection and treatment with rapid response, high sensitivity, and simple operation. A peptide CF4KYP (C, cysteine; F4, phenylalanine tetrapeptide; K, lysine; [...] Read more.
Bacterial infections seriously threaten human safety. Therefore, it is very important to develop a method for bacterial detection and treatment with rapid response, high sensitivity, and simple operation. A peptide CF4KYP (C, cysteine; F4, phenylalanine tetrapeptide; K, lysine; YP, phosphorylated tyrosine) functionalized gold nanoparticle (AuNPs-CF4KYP) was synthesized for simultaneous detection and treatment of bacteria based on bacterial alkaline phosphatase (ALP). In solution, ALP can induce AuNPs-CF4KYP aggregation and produce significant color changes. After encountering bacteria, monodisperse AuNPs-CF4KYP can aggregate/assemble in situ on the surface of the bacterial membrane, change the color of the solution from wine red to grey, destroy the bacterial membrane structure, and induce the production of a large number of reactive oxygen species within the bacteria. The absorption change of AuNPs-CF4KYP solution has a good linear relationship with the number of bacteria. Furthermore, the aggregation of AuNPs-CF4KYP kills approximately 80% of Salmonella typhimurium. By combining enzyme-instructed peptide self-assembly technology and colorimetric analysis technology, we achieve rapid and sensitive colorimetric detection and killing of bacteria. Full article
(This article belongs to the Special Issue Nanoparticles in Chemical and Biological Sensing)
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23 pages, 4337 KiB  
Review
Recent Progress in Multifunctional Gas Sensors Based on 2D Materials
by Zhifang Liu, Zirui Qiao, Chen-Yuan Li and Yilin Sun
Chemosensors 2023, 11(9), 483; https://doi.org/10.3390/chemosensors11090483 - 1 Sep 2023
Cited by 48 | Viewed by 1964
Abstract
The detection of specific gas components under various working conditions while at the same time realizing other functions with the same devices has emerged through great efforts due to these devices’ superior energy-saving and high-efficiency properties. Although so-called multifunctional gas sensors have been [...] Read more.
The detection of specific gas components under various working conditions while at the same time realizing other functions with the same devices has emerged through great efforts due to these devices’ superior energy-saving and high-efficiency properties. Although so-called multifunctional gas sensors have been fabricated with various novel materials, two-dimensional (2D) materials with unique physical and chemical properties used in multifunctional gas sensors have not yet been well studied. In this review, we summarize up-to-date multifunctional gas sensors based on different 2D materials, including graphene and its derivatives, transition metal dichalcogenides (TMDs), MXenes, etc. The progress of machine learning and artificial intelligence used in emerging powerful sensors is introduced. Their sensing abilities and mechanisms are discussed, and further smart devices equipped with IoT platforms and 5G communication are expected for future electronic use. Full article
(This article belongs to the Special Issue Emerging 2D Materials for Sensing Applications)
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12 pages, 2706 KiB  
Article
Novel Electrochemical Sensor Based on MnO2 Nanowire Modified Carbon Paper Electrode for Sensitive Determination of Tetrabromobisphenol A
by Chunmao Zhu, Qi Wu, Fanshu Yuan, Jie Liu, Dongtian Wang and Qianli Zhang
Chemosensors 2023, 11(9), 482; https://doi.org/10.3390/chemosensors11090482 - 1 Sep 2023
Cited by 1 | Viewed by 1200
Abstract
In this paper, a MnO2 nanowire (MnO2-NW) modified carbon paper electrode (CP) was developed as a novel electrochemical sensor for the sensitive determination of tetrabromobisphenol A (TBBPA). The MnO2 nanowire was prepared by a hydrothermal synthesis method, and the [...] Read more.
In this paper, a MnO2 nanowire (MnO2-NW) modified carbon paper electrode (CP) was developed as a novel electrochemical sensor for the sensitive determination of tetrabromobisphenol A (TBBPA). The MnO2 nanowire was prepared by a hydrothermal synthesis method, and the morphology and structure of MnO2 were characterized using scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The electrochemical performance of TBBPA on MnO2-NW/CP was investigated by cyclic voltammetry, and the result confirmed that MnO2-NW/CP exhibited excellent sensitivity for the determination of TBBPA due to the high specific surface area and good electrical conductivity of the nanowire-like MnO2. Moreover, the important electrochemical factors such as pH value, incubation time and modified material proportion were systematically studied to improve the determination sensitivity. The interferences from similar structure compounds on TBBPA have also been investigated. Under the optimal conditions, MnO2-NW/CP displayed a linear range of 70~500 nM for TBBPA with a detection limit of 3.1 nM. This was superior to some electrochemical methods in reference. The work presents a novel and simple method for the determination of TBBPA. Full article
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32 pages, 5140 KiB  
Review
Recent Advances in Functionalization Strategies for Biosensor Interfaces, Especially the Emerging Electro-Click: A Review
by Feiyu Wang, Yiwen Xie, Weijie Zhu and Tianxiang Wei
Chemosensors 2023, 11(9), 481; https://doi.org/10.3390/chemosensors11090481 - 1 Sep 2023
Viewed by 1569
Abstract
The functionalization of biosensor interfaces constitutes a crucial aspect of biosensing systems, as it directly governs key characteristics, including sensitivity, selectivity, accuracy, and rapidity. Among the diverse range of functionalization strategies available for biosensor interfaces, the click reaction has emerged as an exceptionally [...] Read more.
The functionalization of biosensor interfaces constitutes a crucial aspect of biosensing systems, as it directly governs key characteristics, including sensitivity, selectivity, accuracy, and rapidity. Among the diverse range of functionalization strategies available for biosensor interfaces, the click reaction has emerged as an exceptionally straightforward and stable approach for modifying electrodes and sensing films. Notably, the electro-click reaction enables the reagent-free functionalization of the biosensing interface, offering significant advantages, such as high speed, selectivity, and minimal pollution. Consequently, this strategy has garnered substantial attention and is widely regarded as a promising avenue for enhancing biosensor interface functionalization. Within this comprehensive review, we commence by presenting the latest advancements in functionalized biosensor interfaces, organizing the regulatory strategies into distinct categories based on the mediators employed, ranging from nanomaterials to biomolecules. Subsequently, we provide a comprehensive summary with an emphasis on recently developed electro-click strategies for functionalizing electrochemical and optical biosensor interfaces, covering both principles and applications. It is our anticipation that gaining a profound understanding of the principles and applications underlying electro-click strategies for biosensor interface functionalization will facilitate the design of highly selective and sensitive biosensor systems for diverse domains, such as clinical, pharmaceutical, environmental, and food analyses. Full article
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11 pages, 1899 KiB  
Article
Electrochemical Etching-Assisted Fabrication of Quantum Tunneling Sensing Probes with Controlled Nanogap Width
by Bangrui Shao, Qiuxiang He, Tao Jiang, Biaofeng Zeng, Cuifang Kuang, Xu Liu and Longhua Tang
Chemosensors 2023, 11(9), 480; https://doi.org/10.3390/chemosensors11090480 - 1 Sep 2023
Viewed by 1290
Abstract
Quantum tunneling electrical probes, consisting of a pair of nanoelectrodes with a gap width of less than 5 nm, can be used as a robust electrical sensing platform for the detection of various nanoscale objects. To achieve this, stable and gap-width-controllable electrodes are [...] Read more.
Quantum tunneling electrical probes, consisting of a pair of nanoelectrodes with a gap width of less than 5 nm, can be used as a robust electrical sensing platform for the detection of various nanoscale objects. To achieve this, stable and gap-width-controllable electrodes are essential. Although various methods, including lithography and electrochemical strategies, have been proposed for the fabrication of tunneling electrodes, the ability to precisely control the gap width and ensure reproducibility is still lacking. Here, we report a feedback-controlled electrochemical etching approach to fabricate the tunneling electrodes with a controlled nanogap. The connected nanoelectrodes, derived from a dual-barrel nanopipette, were subjected to a controlled electrochemical etching process from a short-circuited state to a tunneling gap. The resulting tunneling electrodes exhibited solvent-response current–voltage electrical behavior, which was well fitted with the Simons model, indicating the formation of tunneling electrodes. Overall, a success rate of more than 60% could be achieved to obtain the tunneling gaps. Furthermore, to verify the function of tunneling electrodes, we used the etched-tunneling electrodes for free-diffusing protein detection, showing the potential of etched-tunneling electrodes as single-molecule sensors. Full article
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