Sensors International最新文献

This work reports on advances in capacitive humidity and strain sensor technologies through the development of state-of-the-art 3D-printed Interdigitated Electrodes (IDEs) coated with a unique GO/ PVA coating. These IDEs are constructed using a novel composite filament of MWCNTs and polylactic acid (PLA) that offer superior flexural strength and electrical properties compared to conventional polymer matrices.

We show that the GO/ PVA coating appears to be sensitive over the full range of relative humidity (RH) from 0% to 100%, with a remarkable capacitance change of 300 pF/%RH. Fast response and recovery times of 60 and 42 s, respectively, have been measured outperforming existing works that utilize metal electrodes. Regarding temperature dependence, the coatings endure conditions ranging from ambient to −25 °C, even in the presence of ice. Furthermore, at 50% RH, the sensors are shown to achieve a maximum sensitivity of 34.2 within a strain range of up to 2%.

In conclusion, this work represents a significant advancement in cutting-edge sensor technologies, offering unprecedented capabilities for humidity and strain sensing performance for a wide range of applications.

The development of valuable Non-enzymatic glucose sensors relies extensively on the design of sensitive and cost-effective materials with high catalytic activity for the efficient electro-oxidation of glucose. In this work, nitrogen-doped reduced graphene aerogel decorated with Yb₂O₃ nanoparticles (GA:N–Yb₂O₃) was prepared via a simple one-step hydrothermal method. Then this conductive porous three-dimensional scaffold was employed as an excellent substrate for hosting nickel nitride (Ni₃N) nanoparticles (NPs). Electrochemical investigation confirmed the beneficial role of GA:N–Yb₂O₃ for enhancing Ni₃N NPs catalytic activity. This sensor shows low glucose oxidation potential, a low detection limit, and high sensitivity. Using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), chronoamperometry, and amperometry, the electrochemical activity of the electrode towards the oxidation of glucose was investigated. The GA:N–Yb₂O₃/Ni₃N glassy carbon electrode (GCE) modifier was well applied as an electrocatalyst for sensing glucose with the detection limit of 3.9 μM, and the sensitivity of 247.1 μA mM⁻¹cm⁻². Impressively, ascorbic acid, acetaminophen, dopamine, uric acid, and sodium chloride oxidation interference could also be avoided. Nonetheless, the selectivity and stability of the Non-enzymatic glucose sensors were quite good. Hence, this new Non-enzymatic sensor can have a reliable potential application in glucose detection.

High intakes of histamine are poisonous. Hence, determining histamine levels in fisheries and processed products is essential to food quality. Several colorimetric sensors based on gold nanoparticles have shown exemplary performance in detecting the presence of histamine in samples. The modified AuNPs by MnO₂ were used as a reagent in histamine analysis by UV–Vis spectrophotometry. Using a seed-mediated growth method, modified Au–MnO2 nanostructures were synthesized from citrate-coated AuNPs and KMnO4. The Au–MnO₂ nanostructure synthesis process produced a yellow-green solution, which produced a crystalline solid with a particle size <100 nm by evaporation. These nanoparticles comprise AuNPs and MnO₂ components, which still perform their original properties. Application of Au–MnO₂ nanostructure in histamine spectrophotometry has values in sensitivity of 0.0344 ppm, detection limit of 0.185 ppm, quantification limit of 0.618 ppm, and accuracy of 95–101 %. Based on analytical results, the effectiveness of synthesizing Au–MnO₂ nanostructure to form complexes with histamine content was low, and it was due to the weak binding between the imidazole group of histamine and Au–MnO₂ nanostructures. Therefore, further investigation on the composition of the Mn metal or the selection of other metals is needed to use Au–MnO₂ as candidate histamine biosensors.

Biosensors have the potential to revolutionize healthcare by providing rapid and accurate diagnosis of diseases. Biosensors are analytical devices that convert molecular recognition of a target analyte into a measurable signal. Older diagnostic techniques, such as immunoaffinity column assays, fluorometric, and enzyme-linked immunosorbent assays, are laborious, require qualified personnel, and can be time consuming. In contrast, biosensors offer improved accuracy, sustainability, and rapidness due to their ability to detect specific biomarkers with high sensitivity and specificity. The review covers various bacterial cellulose (BC)-based biosensors, from SARS-CoV-2 detection to wearable health monitoring and interaction with human-computer interfaces. BC's integration into ionic thermoelectric hydrogels for wearable health monitoring shows its potential for real-time health tracking. Incorporating BC in biosensors for low-noise electrodes, and wearable sensors has been elaborated. The invention of a phage-immobilized BC biosensor for S. aureus detection is a significant contribution to the field, highlighting the biosafety and efficiency of BC in pathogen identification and demonstrating BC's versatility across multiple sensing platforms. Palladium nanoparticle-bacterial cellulose hybrid nanofibers show excellent electrocatalytic activity for dopamine detection, whereas Au-BC nanocomposite biosensors show efficacy in glucose detection, with potential therapeutic applications. The “lab-on-nanopaper” device, utilizing BC nanopaper, not only visually detects human serum albumin but also establishes itself as a new-generation optical biosensing platform with superiority over conventional substrates. This review contributes to the ongoing advancements in biosensor technology, highlighting the potential of BC as a versatile material for developing innovative biosensors. This is crucial for improving the accuracy, sensitivity, and efficiency of diagnostic tools in healthcare.

This comprehensive review provides an in-depth overview of the green (biological) synthesis, characterization, and biosensor applications of metal nanoparticles (NPs). Because of their unique physical and chemical properties, high surface area, and nanoscale size, NPs have become crucial in various fields. The review emphasizes the synthesis, properties, and applications of several metal NPs, particularly silver (AgNPs), gold (AuNPs), platinum (PtNPs), copper (CuNPs), zinc oxide (ZnONPs), iron oxide (FeONPs), and palladium (PdNPs). Green synthesis methods, a truly innovative approach, utilize biological substances such as plant extracts, bacteria, fungi, and yeast. These methods offer environmentally friendly and biologically compatible alternatives to conventional chemical synthesis techniques. This review details these sustainable approaches and their advantages over traditional methods. These natural sources provide an abundant, cost-effective, and environmentally sustainable alternative for NP production. The importance of thorough characterization of nanoparticles is also discussed, highlighting techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and UV–Vis spectroscopy to analyze the size, shape, surface properties, structural integrity, and optical behavior of the NPs. The review highlights the vast potential of metal NPs in biosensors, which play a critical role in medical diagnostics, environmental monitoring, and food safety. Incorporating metal NPs in electrochemical, optical, thermometric, and piezoelectric biosensors significantly enhances sensitivity and specificity, enabling rapid and real-time detection of various analytes.

Fluorescent probes play a crucial role in analytical chemistry and biological imaging, offering selective detection of metal ions. Herein, we present the synthesis and characterization of a novel rhodamine-based fluorescent probe, RbHC (Rhodamine B Helicin), which was obtained through the condensation of rhodamine B hydrazide and helicin in ethanol. The probe demonstrates remarkable selectivity and anti-interference capabilities towards Cu²⁺ and Fe³⁺ ions in 80% acetonitrile solution. Spectral titration analysis revealed a linear relationship between the intensity and the concentration of Cu²⁺/Fe³⁺. The formation of complex between Cu²⁺/Fe³⁺ and RbHC was confirmed to be 1:1, and it was further confirmed by ESI mass spectroscopy and DFT calculations. The coordination with Cu²⁺/Fe³⁺ caused the opening of RbHC's spirolactam ring, resulting in distinct color change and red fluorescence emissions. Moreover, RbHC exhibits high stability and water solubility under both acidic and neutral conditions, enabling its application in the imaging of plant tissues. Besides, the absorption intensity of RbHC–Cu²⁺ increased significantly when exposed to sunshine and 365 nm UV radiation, indicating that it might be used as a potential indicator for measuring outdoor UV intensity.

Nanotechnology, the manipulation of materials at the nanoscale, has emerged as a transformative force with profound implications for diverse fields. This following review explores the versatile administration of nanotechnology in both the biomedical and food processing disciplines, highlighting the potential breakthroughs and advancements achieved in these critical domains. Nanotechnology has made significant advancements in drug delivery, imaging, and diagnostics possible in the biomedical field. Particular characteristics of nanoscale materials, like nanoparticles and nanocarriers, improve their compatibility with biological systems. As a result, targeted drug delivery systems have been created, enabling precise drug administration and fewer side effects. Furthermore, improved diagnostic capabilities are made possible by nanoscale imaging agents, which allow for early disease detection. Additionally, the development of nanosensors for the real-time tracking of physiological variables has been made possible by nanotechnology, which has aided in the rise of personalized medicine. Nanotechnology has completely changed a number of aspects of the food processing industry, including packaging, preservation, and food safety. Antimicrobial nanomaterials have been used to put an end to the growth of harmful microorganisms, thus increasing food safety. Additionally, food packaging using nanocomposites has shown to have enhanced barrier qualities, extending the shelf life of perishable items and cutting down on food waste. The creation of intelligent packaging systems that can continuously check the freshness of food is made possible by nanoscale materials. The use of nanotechnology in these fields presents ethical and safety issues, despite its enormous potential. In order to ensure the responsible integration of nanotechnology into biomedical and food processing practices, ongoing research is devoted to addressing these challenges. The ongoing investigation of nanotechnology's potential in these fields offers hope for the development of safer, more effective, and technologically sophisticated solutions that will improve human health and welfare.

In this modern era, maintaining a sustainable environment is pivotal and hence, a detailed review on gas sensors for quantification of toxic environmental pollutants is critical. In this paper, an extensive review on advancements in gas sensors developed using graphene-metal sulfide composites is discussed. Although graphene is an intriguing material with high sensitivity for determination of gases at low concentrations, its poor selectivity is a hindrance towards fabrication of high-performance gas sensors. Hence, hybrid nanocomposites prepared by embedding graphene and its derivatives with various metal sulfides including molybdenum sulfide (MoS₂), tin sulfide (SnS₂), tungsten sulfide (WS₂), cadmium sulfide (CdS) etc. were utilized in gas sensor fabrication with enhanced sensing capabilities. Related investigations revealed that gas sensors using graphene-metal sulfide nanohybrids could be effectively used in detection of individual molecules of toxic gas including NO_x, NH₃, H₂S, SO_2, HCHO, CO₂, CO, CH₄, C₃H₆O and so on at very low concentrations with good sensitivity and selectivity. A comparative evaluation of various performance parameters revealed that toxic gases were determined with a limit of detection and concentration as low as 0.6 ppb and 0.05 ppm respectively, using graphene-metal sulfide based gas sensors. This review reflects the fact that advancements in material synthesis has led to improvement in gas sensing performances as evidenced from the comparatively better performance metrics reported in recently published articles which utilized hybrid nanocomposites as sensing material.

Internet of Things (IoT) networks rely on wireless sensors for data collection and transmission, making them vulnerable to security threats that undermine their Quality of Service (QoS). The Routing Protocol for Low-Power and Lossy Networks (RPL) is crucial for efficient data transmission in IoT networks, but its performance can be significantly degraded by attacks such as Rank, Sinkhole and Wormhole attacks. These threats disrupt network integrity by manipulating routing information, attracting traffic through malicious nodes and tunneling data to malicious endpoints. This paper presents a novel machine learning-based framework to enhance RPL's security and QoS. Our approach integrates a random forest model for precise traffic classification, a reinforcement learning module for dynamic and adaptive routing, and a modified RPL objective function that incorporates classification outcomes into routing decisions. Simulations demonstrate that our framework significantly improves network throughput, reduces latency, and enhances packet delivery ratios while maintaining low jitter. Furthermore, it achieves a high detection rate, minimal false positives, and swift response to security incidents, thereby robustly securing the RPL protocol and enhancing QoS in IoT-enabled wireless sensor networks. The findings of this research offer substantial contributions to the field, providing a comprehensive solution to strengthen RPL against prevalent security threats.

The integration of Artificial Intelligence (AI) and Internet of Things (IoT) technologies is transforming precision agriculture by enhancing crop monitoring and management. This review explores cutting-edge methodologies and innovations in modern agriculture, including high-throughput phenotyping, remote sensing, and automated agricultural robots (AgroBots). These technologies automate tasks such as harvesting, sorting, and weed detection, significantly reducing labor costs and environmental impacts. High-throughput phenotyping leverages remote sensing, spectral imaging, and robotics to collect data on plant traits, enabling informed decisions on fertilization, irrigation, and pest management. DGPS and remote sensing offer precise, real-time data essential for soil condition assessment and crop health monitoring. Advanced image segmentation techniques ensure accurate detection of plants and fruits, overcoming challenges posed by varying lighting conditions and complex backgrounds. Case studies like the PACMAN SCRI project for apple crop load management and Project PANTHEON's SCADA system for hazelnut orchard management demonstrate the transformative potential of AI and IoT in optimizing agricultural practices. The upcoming integration of 5G and future 6G mobile networks promises to address connectivity challenges, promoting the widespread adoption of smart agricultural practices. However, several research gaps remain. Integrating diverse datasets, ensuring scalability for small and medium-sized farms, and enhancing real-time decision-making need further investigation. Developing robust AI models and IoT devices for varied agricultural conditions, creating user-friendly interfaces for farmers, and addressing privacy and security concerns are essential. Addressing these gaps can enhance the effectiveness and adoption of AI and IoT in precision agriculture, leading to more sustainable and productive farming practices.