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Nano-Functional Materials for Sensor Applications

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Nanochemistry".

Deadline for manuscript submissions: 31 July 2024 | Viewed by 9075

Special Issue Editors


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Guest Editor
Center for Advanced Material Diagnostic Technology, College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, China
Interests: sensors; photochromic; semiconductor
School of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
Interests: biosensor; electroanalysis; graphene; biometric identification
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

This Special Issue highlights the latest advancements and cutting-edge research on nano-functional materials for sensor applications, focusing on their unique chemical properties at the molecular level. These materials are indispensable for a wide range of applications, including sensors in healthcare, environmental monitoring, and security.

Our esteemed contributors cover a diverse array of topics, from molecular-level interactions in novel fabrication techniques to innovative designs for enhancing the performance of sensors. They also explore the integration of nano-functional materials into existing systems, as well as their potential to enable entirely new sensing platforms. The articles in this Special Issue emphasize the transformative impact of nano-functional materials on sensors, offering insights into their current capabilities and future potential from a chemistry standpoint.

Molecular design and synthesis of nanostructured materials: Discover the latest innovations in the chemical design and synthesis of various nanostructured materials.

Molecular recognition and signal transduction in biosensors: Learn about the underlying chemistry of molecular recognition and signal transduction mechanisms in biosensors, with a focus on their potential applications in healthcare diagnostics, drug delivery, and therapeutics.

Optical and plasmonic sensors at the molecular level: Investigate the role of molecular interactions in the emerging field of nano-plasmonics and its impact on the development of highly sensitive and compact optical sensors.

Wearable and flexible sensors: Delve into the molecular-level engineering of wearable and flexible sensors that incorporate nano-functional materials, which have the potential to revolutionize health monitoring, human–machine interfaces, and other areas of wearable technology.

Molecular-level environmental and security applications: Explore the potential of nano-functional materials for the development of sensors capable of detecting pollutants, radiation, and other threats to human health and security through molecular-level interactions.

Dr. Aiwu Wang
Dr. Li Fu
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • nano-functional materials
  • sensor applications
  • nanotechnology
  • fabrication techniques
  • sensing platforms
  • environmental monitoring
  • healthcare

Published Papers (8 papers)

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Research

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14 pages, 4221 KiB  
Article
In Situ-Derived N-Doped ZnO from ZIF-8 for Enhanced Ethanol Sensing in ZnO/MEMS Devices
by Meihua Liang, Yong Yan, Jiaxuan Yang, Xiaodong Liu, Rongrong Jia, Yuanyuan Ge, Zhili Li and Lei Huang
Molecules 2024, 29(8), 1703; https://doi.org/10.3390/molecules29081703 - 10 Apr 2024
Viewed by 1707
Abstract
Microelectromechanical systems (MEMS) gas sensors have numerous advantages such as compact size, low power consumption, ease of integration, etc., while encountering challenges in sensitivity and high resistance because of their low sintering temperature. This work utilizes the in situ growth of Zeolitic Imidazolate [...] Read more.
Microelectromechanical systems (MEMS) gas sensors have numerous advantages such as compact size, low power consumption, ease of integration, etc., while encountering challenges in sensitivity and high resistance because of their low sintering temperature. This work utilizes the in situ growth of Zeolitic Imidazolate Framework-8 (ZIF-8) followed by its conversion to N-doped ZnO. The results obtained from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicate that the in situ derivation of ZIF-8 facilitates the adhesion of ZnO particles, forming an island-like structure and significantly reducing the interfaces between these particles. Furthermore, powder X-ray diffraction (XRD) analysis, elemental mapping, and X-ray photoelectron spectroscopy (XPS) analysis confirm the conversion of ZIF-8 to ZnO, the successful incorporation of N atoms into the ZnO lattice, and the creation of more oxygen vacancies. The ZIF-8-derived N-doped ZnO/MEMS sensor (ZIF (3)-ZnO/MEMS) exhibits remarkable gas sensitivity for ethanol detection. At an operating temperature of 290 °C, it delivers a substantial response value of 80 towards 25 ppm ethanol, a 13-fold enhancement compared with pristine ZnO/MEMS sensors. The sensor also exhibits an ultra-low theoretical detection limit of 11.5 ppb to ethanol, showcasing its excellent selectivity. The enhanced performance is attributed to the incorporation of N-doped ZnO, which generates abundant oxygen vacancies on the sensor’s surface, leading to enhanced interaction with ethanol molecules. Additionally, a substantial two-order-of-magnitude decrease in the resistance of the gas-sensitive film is observed. Overall, this study provides valuable insights into the design and fabrication strategies applicable to high-performance MEMS gas sensors in a broader range of gas sensing. Full article
(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)
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14 pages, 1744 KiB  
Article
Catalase Detection via Membrane-Based Pressure Sensors
by Monica Bianco, Alessandra Zizzari, Elisabetta Perrone, Diego Mangiullo, Marco Mazzeo, Ilenia Viola and Valentina Arima
Molecules 2024, 29(7), 1506; https://doi.org/10.3390/molecules29071506 - 28 Mar 2024
Viewed by 485
Abstract
Membrane-based sensors (MePSs) exhibit remarkable precision and sensitivity in detecting pressure changes. MePSs are commonly used to monitor catalytic reactions in solution, generating gas products crucial for signal amplification in bioassays. They also allow for catalyst quantification by indirectly measuring the pressure generated [...] Read more.
Membrane-based sensors (MePSs) exhibit remarkable precision and sensitivity in detecting pressure changes. MePSs are commonly used to monitor catalytic reactions in solution, generating gas products crucial for signal amplification in bioassays. They also allow for catalyst quantification by indirectly measuring the pressure generated by the gaseous products. This is particularly interesting for detecting enzymes in biofluids associated with disease onset. To enhance the performance of a MePS, various structural factors influence membrane flexibility and response time, ultimately dictating the device’s pressure sensitivity. In this study, we fabricated MePSs using polydimethylsiloxane (PDMS) and investigated how structural modifications affect the Young’s modulus (E) and residual stress (σ0) of the membranes. These modifications have a direct impact on the sensors’ sensitivity to pressure variations, observed as a function of the volume of the chamber (Σ) or of the mechanical properties of the membrane itself (S). MePSs exhibiting the highest sensitivities were then employed to detect catalyst quantities inducing the dismutation of hydrogen peroxide, producing dioxygen as a gaseous product. As a result, a catalase enzyme was successfully detected using these optimized MePSs, achieving a remarkable sensitivity of (22.7 ± 1.2) µm/nM and a limit of detection (LoD) of 396 pM. Full article
(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)
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13 pages, 4690 KiB  
Article
Silver Nanoparticle-Embedded Hydrogels for Electrochemical Sensing of Sulfamethoxazole Residues in Meat
by Yuanxi Deng and Ningning Yang
Molecules 2024, 29(6), 1256; https://doi.org/10.3390/molecules29061256 - 12 Mar 2024
Viewed by 671
Abstract
A disposable electrochemical sensor based on silver nanoparticle-embedded cellulose hydrogel composites was developed for sensitive detection of sulfamethoxazole residues in meat samples. Scanning electron microscopy confirmed the porous structure of the cellulose matrix anchored with 20–50 nm silver nanoparticles (AgNPs). Fourier transform infrared [...] Read more.
A disposable electrochemical sensor based on silver nanoparticle-embedded cellulose hydrogel composites was developed for sensitive detection of sulfamethoxazole residues in meat samples. Scanning electron microscopy confirmed the porous structure of the cellulose matrix anchored with 20–50 nm silver nanoparticles (AgNPs). Fourier transform infrared spectroscopy and X-ray diffraction verified that the metallic AgNPs coordinated with the amorphous cellulose chains. At an optimum 0.5% loading, the nanocomposite sensor showed a peak-to-peak separation of 150 mV, diffusion-controlled charge transfer kinetics, and an electron transfer coefficient of 0.6 using a ferro/ferricyanide redox probe. Square-wave voltammetry was applied for sensing sulfamethoxazole based on its two-electron oxidation peak at 0.72 V vs. Ag/AgCl in Britton–Robinson buffer of pH 7.0. A linear detection range of 0.1–100 μM sulfamethoxazole was obtained with a sensitivity of 0.752 μA/μM and limit of detection of 0.04 μM. Successful recovery between 86 and 92% and less than 6% RSD was achieved from spiked meat samples. The key benefits of the proposed disposable sensor include facile fabrication, an antifouling surface, and a reliable quantification ability, meeting regulatory limits. This research demonstrates the potential of novel cellulose–silver nanocomposite materials towards developing rapid, low-cost electroanalytical devices for decentralized on-site screening of veterinary drug residues to ensure food safety. Full article
(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)
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12 pages, 2805 KiB  
Article
Rapid Detection of the Anti-Tumor Drug Etoposide in Biological Samples by Using a Nanoporous-Gold-Based Electrochemical Sensor
by Huiyuan Yu, Mengjie Hu, Xiaolei Wang, Xia Wang, Luying Xun and Honglei Liu
Molecules 2024, 29(5), 1060; https://doi.org/10.3390/molecules29051060 - 28 Feb 2024
Viewed by 645
Abstract
Monitoring etoposide is important due to its wide usage in anti-tumor therapy; however, the commonly used HPLC method is expensive and often requires complicated extraction and detection procedures. Electrochemical analysis has great application prospects because of its rapid response and high specificity, sensitivity, [...] Read more.
Monitoring etoposide is important due to its wide usage in anti-tumor therapy; however, the commonly used HPLC method is expensive and often requires complicated extraction and detection procedures. Electrochemical analysis has great application prospects because of its rapid response and high specificity, sensitivity, and efficiency with low cost and high convenience. In this study, we constructed a nanoporous gold (NPG)-modified GCE for the detection of etoposide. The electrochemical oxidation of etoposide by NPG caused a sensitive current peak at +0.27 V with good reproductivity in 50 mM of phosphate buffer (pH 7.4). The relationship between etoposide concentration and peak current was linear in the range between 0.1 and 20 μM and between 20 and 150 μM, with a detection sensitivity of 681.8 μA mM−1 cm−2 and 197.2 μA mM−1 cm−2, respectively, and a limit of detection (LOD) reaching 20 nM. The electrode had a good anti-interference ability to several common anions and cations. Spiked recovery tests in serum, urine, and fermentation broth verified the excellent performance of the sensor in terms of sensitivity, reproducibility, and specificity. This may provide a promising tool for the detection of etoposide in biological samples. Full article
(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)
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11 pages, 1352 KiB  
Article
Changes in the Main Physicochemical Properties and Electrochemical Fingerprints in the Production of Sea Buckthorn Juice by Pectinase Treatment
by Kaihua Guo
Molecules 2024, 29(5), 1035; https://doi.org/10.3390/molecules29051035 - 28 Feb 2024
Viewed by 601
Abstract
Enzymatic hydrolysis using pectinase is critical for producing high-yield and quality sea buckthorn juice. This study determined the optimal temperature, time, and enzyme dosage combinations to guide manufacturers. A temperature of 60 °C, hydrolysis time of 3 h, and 0.3% enzyme dosage gave [...] Read more.
Enzymatic hydrolysis using pectinase is critical for producing high-yield and quality sea buckthorn juice. This study determined the optimal temperature, time, and enzyme dosage combinations to guide manufacturers. A temperature of 60 °C, hydrolysis time of 3 h, and 0.3% enzyme dosage gave 64.1% juice yield—25% higher than without enzymes. Furthermore, monitoring physicochemical properties reveals enzyme impacts on composition. Higher dosages increase soluble solids up to 15% and soluble fiber content by 35% through cell wall breakdown. However, excessive amounts over 0.3% decrease yields. Pectin concentration also declines dose-dependently, falling by 91% at 0.4%, improving juice stability but needing modulation to retain viscosity. Electrochemical fingerprinting successfully differentiates process conditions, offering a rapid quality control tool. Its potential for commercial inline use during enzymatic treatment requires exploration. Overall, connecting optimized parameters to measured effects provides actionable insights for manufacturers to boost yields, determine enzyme impacts on nutrition/functionality, and introduce novel process analytical technology. Further investigations of health properties using these conditions could expand sea buckthorn juice functionality. Full article
(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)
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11 pages, 2622 KiB  
Article
Preparation of β-Cyclodextrin Functionalized Platform for Monitoring Changes in Potassium Content in Perspiration
by Ruixiang Liu and Xiaofeng Shi
Molecules 2023, 28(19), 7000; https://doi.org/10.3390/molecules28197000 - 9 Oct 2023
Viewed by 877
Abstract
The monitoring of potassium ion (K+) levels in human sweat can provide valuable insights into electrolyte balance and muscle fatigue non-invasively. However, existing laboratory techniques for sweat testing are complex, while wearable sensors face limitations like drift, fouling and interference from [...] Read more.
The monitoring of potassium ion (K+) levels in human sweat can provide valuable insights into electrolyte balance and muscle fatigue non-invasively. However, existing laboratory techniques for sweat testing are complex, while wearable sensors face limitations like drift, fouling and interference from ions such as Na+. This work develops printed electrodes using β-cyclodextrin functionalized reduced graphene oxide (β-CD-RGO) for selective K+ quantification in sweat. The β-CD prevents the aggregation of RGO sheets while also providing selective binding sites for K+ capture. Electrodes were fabricated by screen printing the β-CD-RGO ink onto conductive carbon substrates. Material characterization confirmed the successful functionalization of RGO with β-CD. Cyclic voltammetry (CV) showed enhanced electrochemical behavior for β-CD-RGO-printed electrodes compared with bare carbon and RGO. Sensor optimization resulted in a formulation with 30% β-CD-RGO loading. The printed electrodes were drop-casted with an ion-selective polyvinyl chloride (PVC) membrane. A linear range from 10 μM to 100 mM was obtained along with a sensitivity of 54.7 mV/decade. The sensor showed good reproducibility over 10 cycles in 10 mM KCl. Minimal interference from 100 mM Na+ and other common sweat constituents validated the sensor’s selectivity. On-body trials were performed by mounting the printed electrodes on human subjects during exercise. The K+ levels measured in sweat were found to correlate well with serum analysis, demonstrating the sensor’s ability for non-invasive electrolyte monitoring. Overall, the facile synthesis of stable β-CD-RGO inks enables the scalable fabrication of wearable sensors for sweat potassium detection. Full article
(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)
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10 pages, 2011 KiB  
Article
Fabry–Pérot Cavities with Suspended Palladium Membranes on Optical Fibers for Highly Sensitive Hydrogen Sensing
by Feng Xu, Jun Ma, Can Li, Churong Ma, Jie Li, Bai-Ou Guan and Kai Chen
Molecules 2023, 28(19), 6984; https://doi.org/10.3390/molecules28196984 - 9 Oct 2023
Cited by 1 | Viewed by 929
Abstract
Hydrogen (H2) sensors are critical to various applications such as the situation where H2 is used as the clean energy for industry or the indicator for human disease diagnosis. Palladium (Pd) is widely used as the hydrogen sensing material in [...] Read more.
Hydrogen (H2) sensors are critical to various applications such as the situation where H2 is used as the clean energy for industry or the indicator for human disease diagnosis. Palladium (Pd) is widely used as the hydrogen sensing material in different types of sensors. Optical fiber H2 sensors are particularly promising due to their compactness and spark-free operation. Here, we report a Fabry–Pérot (FP)-cavity-based H2 sensor that is formed with a freestanding Pd membrane and integrated on a conventional single-mode optical fiber end. The freestanding Pd membrane acts both as the active hydrogen sensing material and as one of the reflective mirrors of the cavity. When the Pd film absorbs H2 to form PdHx, it will be stretched, resulting in a change of the cavity length and thus a shift of the interference spectrum. The H2 concentration can be derived from the amplitude of the wavelength shift. Experimental results showed that H2 sensors based on suspended Pd membranes can achieve a detection sensitivity of about 3.6 pm/ppm and a detection limit of about 3.3 ppm. This highly sensitive detection scheme is expected to find applications for sensing low-concentration H2. Full article
(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)
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Review

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25 pages, 3980 KiB  
Review
A Review of Recent Progress in Drug Doping and Gene Doping Control Analysis
by Yuze Lu, Jiayu Yan, Gaozhi Ou and Li Fu
Molecules 2023, 28(14), 5483; https://doi.org/10.3390/molecules28145483 - 18 Jul 2023
Cited by 4 | Viewed by 2706
Abstract
The illicit utilization of performance-enhancing substances, commonly referred to as doping, not only infringes upon the principles of fair competition within athletic pursuits but also poses significant health hazards to athletes. Doping control analysis has emerged as a conventional approach to ensuring equity [...] Read more.
The illicit utilization of performance-enhancing substances, commonly referred to as doping, not only infringes upon the principles of fair competition within athletic pursuits but also poses significant health hazards to athletes. Doping control analysis has emerged as a conventional approach to ensuring equity and integrity in sports. Over the past few decades, extensive advancements have been made in doping control analysis methods, catering to the escalating need for qualitative and quantitative analysis of numerous banned substances exhibiting diverse chemical and biological characteristics. Progress in science, technology, and instrumentation has facilitated the proliferation of varied techniques for detecting doping. In this comprehensive review, we present a succinct overview of recent research developments within the last ten years pertaining to these doping detection methodologies. We undertake a comparative analysis, evaluating the merits and limitations of each technique, and offer insights into the prospective future advancements in doping detection methods. It is noteworthy that the continual design and synthesis of novel synthetic doping agents have compelled researchers to constantly refine and innovate doping detection methods in order to address the ever-expanding range of covertly employed doping agents. Overall, we remain in a passive position for doping detection and are always on the road to doping control. Full article
(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)
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