Khalida Akhtar , Naila Zubair , Neelam Zeb , Syed Sajjad Ali Shah , Zia Ullah Khan , Hina Khalid
{"title":"Morphology controlled fabrication of zinc phosphate hierarchical microspheres for room temperature ammonia gas sensor","authors":"Khalida Akhtar , Naila Zubair , Neelam Zeb , Syed Sajjad Ali Shah , Zia Ullah Khan , Hina Khalid","doi":"10.1016/j.snr.2025.100288","DOIUrl":"10.1016/j.snr.2025.100288","url":null,"abstract":"<div><div>Hierarchical Zinc phosphate nano/microstructures with controlled morphological features were synthesized in aqueous solutions through simple and economical route without using any type of surfactant or template. SEM analysis revealed novel morphologies of the synthesized powders i.e., hierarchical microspheres, urchin like microspheres, nanoflowers and nanoellipsoids and unfolded that produced morphologies strongly depended upon the applied experimental conditions. Selected batches of the synthesized powders i.e., hierarchical microspheres, urchin like microspheres and hierarchical nanoellipsoids were selected for further analysis using XRD, FT-IR, BET analysis and gas sensing application and termed as Zinc Phosphate 1 (ZP1), Zinc Phosphate 2 (ZP2), and Zinc Phosphate 3 (ZP3), respectively. XRD results confirmed the crystalline nature of the as-prepared powders with crystallite sizes 16.5 nm, 30. 15 nm and 37.01 nm, for ZP1, ZP2 and ZP3, respectively. Evaluation of gas sensing properties of the selected samples revealed that sensors based on ZP1 showed highest gas sensing response of 89 % with response recovery time 31/12 s, towards 5 ppm ammonia at room temperature. In addition, the lowest detection limit was investigated to be <1 ppm. Because of the excellent gas sensing performance, the synthesized zinc phosphate structures could be employed as promising candidates for developing highly sensitive and selective room temperature ammonia gas sensor.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100288"},"PeriodicalIF":6.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158329","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A tactile sensor for recognition of softness using interlocking structure of carbon nanoparticle- polydimethylsiloxane composite","authors":"Sangmin Lee, Jaewon Jang, Wanjun Park","doi":"10.1016/j.snr.2025.100289","DOIUrl":"10.1016/j.snr.2025.100289","url":null,"abstract":"<div><div>This study introduces a novel tactile sensor designed with an interlocking structure of polydimethylsiloxane (PDMS) embedded with carbon nanoparticles (CNP), aimed at enhancing the detection and differentiation of material softness. This sensor emulates the human tactile sense by detecting softness through measuring not only the pressure applied but also the transient state during material deformation to reach the indentation depth, thus providing a comprehensive softness profile. Our results reveal that the sensor effectively recognizes softness across a variety of materials and working environments, considering tolerances against operational variations. This is supported by tests conducted using a one-dimensional convolutional neural network (1D-CNN).</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100289"},"PeriodicalIF":6.5,"publicationDate":"2025-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bo Wang, Shanren Liu, Mengmeng Gao, Yuanjun Li, Heer Yang, Cai Sun, Qi Guo, Yongsen Yu
{"title":"A highly sensitive tapered fiber biosensor modified by PDMS combustion product and graphene oxide for MUC1 detection","authors":"Bo Wang, Shanren Liu, Mengmeng Gao, Yuanjun Li, Heer Yang, Cai Sun, Qi Guo, Yongsen Yu","doi":"10.1016/j.snr.2025.100287","DOIUrl":"10.1016/j.snr.2025.100287","url":null,"abstract":"<div><div>It is a critical challenge to develop reliable, stable, and sensitive biosensors for specific detection of mucin 1 (MUC1). In this paper, a label-free biosensor based on polydimethylsiloxane (PDMS) combustion product and graphene oxide (GO) functionalized tapered fiber (PGTF) was proposed and demonstrated for high sensitivity MUC1 detection. The PDMS combustion product is mainly composed of SiO<sub>2</sub>, which can be firmly bonded to the surface of the fiber, effectively increasing the specific surface area of the fiber. At the same time, the combination of the PDMS combustion product and the fiber cladding material will generate defects in the cladding, resulting in easier leakage of light inside the fiber core. Therefore, a strong evanescent field and interference effect can be obtained without drawing the tapered fiber waist very thin, which contributes to improving the sensitivity of fiber biosensor. In addition, GO has good biological affinity, a large specific surface area, and abundant functional groups, which can provide more binding sites for the attachment of biomolecule. The detection limit of the PGTF is 0.11 pM when the diameter of the fiber taper is 50 μm and modified with five layers of PDMS combustion product. Experimentally demonstrated sensor specificity and reproducibility, indicating that the sensor has a practical value for real applications. The PGTF has great potential as a simple, sensitive, and label-free assay in the field of cancer marker detection.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100287"},"PeriodicalIF":6.5,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143157710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Emerging EM wave sensors for non-invasive glucose monitoring: Review, techniques and developments","authors":"Sudershan Dutt , Rajat Thakur , Abhishek Kandwal , Pawan Kumar , Rohit Jasrotia , Natrayan Lakshmaiya , Louis WY Liu , Sachin Kumar , Bancha Luadang , Choon Kit Chan","doi":"10.1016/j.snr.2025.100282","DOIUrl":"10.1016/j.snr.2025.100282","url":null,"abstract":"<div><div>As a chronic disease, diabetes has impacted millions of individuals across the globe and is spreading at a very fast rate among adults mainly. Continuous observations of essential indicators like pulse rate, arterial pressure, and blood sugar levels, and oxygen saturation are crucial to maintain a healthy life and preventing severe complications associated with these. Using non-invasive method of blood glucose monitoring has paved its way to be one of the most prominent safest technique without harming the skin of the patients. This examination delves into the application of planar resonant sensors utilizing microwaves for quantifying glucose concentrations. The sensors based on RF EM waves mainly operating in the region from few MHz to GHz frequencies have garnered notable attention in the scientific community in recent years due to their significant contributions. They can detect alterations in dielectric properties caused by fluctuations in glucose concentrations. These sensors exhibit electrical reactions that rely on the dielectric properties of their surroundings. This review offers a current assessment of this sensing methodology, categorized by sensing parameters, and suggests typical non-invasive microwave sensor varieties for assessment. It further examines the key aspects of different sensor types, outlines potential future avenues, and addresses challenges in the field of glucose monitoring.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100282"},"PeriodicalIF":6.5,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chaojiang Li , Yuxuan Liu , Guodong Liu , Qifeng Tan , Xiaolong Dou , Yuting Xie , Xianchao Zhang
{"title":"Development of a low-cost flexible potentiometric detector and its integrated system for electrochemical sensing of electrolytes in human sweat","authors":"Chaojiang Li , Yuxuan Liu , Guodong Liu , Qifeng Tan , Xiaolong Dou , Yuting Xie , Xianchao Zhang","doi":"10.1016/j.snr.2025.100286","DOIUrl":"10.1016/j.snr.2025.100286","url":null,"abstract":"<div><div>In the current era of wearable electrochemical sensors, there is a growing demand for a potentiometric detector that exhibits exceptional flexibility, comfortable wearability, and stability in electrolyte sensing. The present study designs and validates a low-cost (costs 17 dollars), small area (size of 4 × 5.8 cm<sup>2</sup>), highly flexible potentiometric detector, which is facilitated through the utilization of cost-effective components, flexible printed circuit boards, and Bluetooth low energy modules. Electrolyte electrochemical detection has been achieved by integrating wearable microfluidic electrochemical sensing devices and establishing wireless communication with smartphone applications. The efficacy of this designed flexible potentiometric detector is demonstrated in sodium and calcium ions detection, indicating comparable results to those obtained from commercial electrochemical workstations. By comparing the detection results with those obtained from ion chromatography, the flexible potentiometric detector is proved to be useful for a real-time, on-body quantitative analysis of various ion concentrations in human sweat.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100286"},"PeriodicalIF":6.5,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Noemi Bellassai , Roberta D'Agata , Giuseppe Spoto
{"title":"Advancements in the integration of isothermal nucleic acid amplification methods for point-of-care testing in resource-limited settings","authors":"Noemi Bellassai , Roberta D'Agata , Giuseppe Spoto","doi":"10.1016/j.snr.2025.100285","DOIUrl":"10.1016/j.snr.2025.100285","url":null,"abstract":"<div><div>Environmental conditions in low-resource areas exert significant pressure on populations, healthcare personnel, and the tools used for disease diagnosis. Fortunately, advancements in molecular assays now allow for rapid and efficient analysis, leading to effective clinical diagnostics and food safety interventions. Additionally, developing microfluidics and nanotechnologies has facilitated the miniaturization of integrated devices for point-of-care (POC) testing. These innovations have improved sensitivity while significantly reducing the time and cost associated with individual analyzes. This review focuses on the applications of molecular diagnostics for POC devices in low-resource settings, with a particular emphasis on isothermal nucleic acid amplification assays integrated into microfluidic platforms. It begins with an overview of the unmet needs for POC testing and its importance in resource-limited areas. Following this, isothermal amplification methods are described, highlighting their advantages and limitations when implemented in POC platforms, along with real-world applications in biological and food matrices in low- and middle-income countries. We then examine the unique features of POC systems, such as the use of low-cost materials for device fabrication, portability, and detection methods that provide rapid and reliable results near the site of patient care. This capability enables early-stage diagnosis and improved clinical management in low-resource environments.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100285"},"PeriodicalIF":6.5,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Gitansh Verma , Shrutidhara Sarma , Eugen Koch , Andreas Dietzel
{"title":"Flexible touch and gesture recognition system for curved surfaces with machine learning for assistive applications","authors":"Gitansh Verma , Shrutidhara Sarma , Eugen Koch , Andreas Dietzel","doi":"10.1016/j.snr.2025.100284","DOIUrl":"10.1016/j.snr.2025.100284","url":null,"abstract":"<div><div>Touch is a fundamental mode of human-machine interaction and ability to monitor tactile pressure, recognize gestures and location of touch are crucial for touch-based technologies. However, achieving reliable touch sensing on curved surfaces remains challenging as flexing often disrupts the stability of sensor outputs and diminishes sensitivity, especially in dynamic environments. This study presents the development of a flexible multi-element touch sensing patch that can monitor its bending state as well as detect pressure with a sensitivity of 0.827 kPa<sup>−1</sup>. The patch is fabricated using resistive strain sensors, screen printed onto a PET sheet with a foam backing. Evaluation electronics were integrated to ensure stable, noise-free signal acquisition, and output was processed with machine learning (ML) algorithms to classify gestures such as single and double finger taps, swipes, and touch locations, with 93 % accuracy, on both flat and curved surfaces. Based on the identified gesture, the system enables users to type text or control external devices with minimal physical effort. Its scalable fabrication, high sensitivity, mechanical resilience and seamless ML integration establishes it as a powerful and efficient tool for assistive technologies, designed to support individuals with limited speech and mobility, such as those with quadriplegia or paralysis.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100284"},"PeriodicalIF":6.5,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manjula B. Wijesinghe , Indika K. Warnakula , Dulan B. Gunasekara , Susan M. Lunte
{"title":"Bipolar electrochemically generated fluorescence detector for microchip electrophoresis with and without a potentiostat: Application to reducible analyte detection","authors":"Manjula B. Wijesinghe , Indika K. Warnakula , Dulan B. Gunasekara , Susan M. Lunte","doi":"10.1016/j.snr.2025.100283","DOIUrl":"10.1016/j.snr.2025.100283","url":null,"abstract":"<div><div>Microchip electrophoresis (ME) is a separation method that makes it possible to quickly analyze multiple species in small volume samples in a miniaturized format. Two commonly employed detection approaches for ME are electrochemistry and fluorescence. Electrochemical detection can be employed for direct detection of analytes via redox chemistry, while fluorescence generally offers lower limits of detection but often requires analyte derivatization. The present study uses bipolar electrochemistry to couple the two detection methods into a single device as a detector for that encompasses the advantages of both techniques. This system employs a closed bipolar electrode (BPE) that converts the cathodic amperometric current produced at the separation (sensing) pole to a fluorescence response generated at the reporting pole. Two model analytes, benzoquinone and resazurin, were separated and detected using ME with reductive amperometric detection at the sensing pole of the BPE. A potentiostat was used to control the bipolar electrode. The response was then converted to fluorescence through the oxidation of 2,7-dichlorodihydrofluorescein in the reporting channel. This system was subsequently modified to run without a potentiostat by using the separation voltage to bias the BPE sensing pole. A voltage applied across the reporting channel was used to generate electroosmotic flow as well as bias the corresponding pole of the BPE. This potentiostat-free mode was evaluated for the determination of 3-nitro-<span>l</span>-tyrosine, a reducible biomarker of oxidative stress. Lastly, a sacrificial electrochemically active species, Trolox®, was incorporated into the reporting channel to compensate for background current at the sensing channel and lower the limits of detection.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100283"},"PeriodicalIF":6.5,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sadaf Maramizonouz , Jeremy J. Hawkes , Mohammad Rahmati , Yong-Qing Fu
{"title":"Continuous flow acoustofluidics in wall-less capillary bridge channels","authors":"Sadaf Maramizonouz , Jeremy J. Hawkes , Mohammad Rahmati , Yong-Qing Fu","doi":"10.1016/j.snr.2024.100275","DOIUrl":"10.1016/j.snr.2024.100275","url":null,"abstract":"<div><div>In this study, the manipulation, patterning, and alignment of yeast particles were successfully demonstrated inside a continuous flow capillary bridge channel. A numerical model is presented to explore various frequencies and channel configurations, and the numerical results are compared to the experimental findings. The numerical model produced results in excellent agreement with the experimental data. Yeast particles were aligned in linear patterns while continuously flowing parallel to the air-water interfaces of the capillary bridge channel. The width of the fluid-guide significantly affected the acoustic pressure fields and thus the quality of particle patterning. Most frequencies can achieve particle alignment inside the capillary bridge channel, while the liquid flow straightens the particle line. Studies of ultrasound transfer from a solid wave-guide into the liquid in a capillary bridge channel have previously shown that some nodes which formed in the waveguide will cross the solid-fluid interface into the water of the capillary bridge. The nodes formed by this extension mechanism are not easily distinguishable from nodes formed by a resonance in the liquid since particles are attracted to them in the same way and the node-to-node separation is often similar. This paper provides further foundation for the new node extension concept and identifies some of its unique features.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100275"},"PeriodicalIF":6.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Resistive pulse sensing of pre-nucleation activities during single-entity lysozyme crystallization on single nanopipettes","authors":"Yusuff Balogun , Ruoyu Yang , Gangli Wang","doi":"10.1016/j.snr.2025.100281","DOIUrl":"10.1016/j.snr.2025.100281","url":null,"abstract":"<div><div>The formation of cluster aggregates in a (super)saturated solution prior to protein nucleation is crucial to overcoming the thermodynamic energy barrier which enables further growth of single crystals. This process is important for single crystal growth, separation and energy conversion among other important applications. For structural determination of biomacromolecules, neutron crystallography holds unique advantages in resolving hydrogen/proton over other structure determination techniques but faces technical obstacles in requiring large high-quality single crystals and preferentially hydrogen-deuterium exchanges. Herein, we explore protein nucleation in heavy water (D<sub>2</sub>O) via nanopore-based resistive pulse sensing, with lysozyme as prototype. By controlling localized supersaturation and phase transition at a nanopore through adjusting the potential waveform, a single protein crystal can be grown. Our focus is on understanding the translocation and/or transformation of protein aggregates through nanopores prior to the irreversible nucleation. As expected, higher protein concentrations tend to facilitate nucleation and growth of a single protein crystal with higher supersaturation, consistent with bulk experiments. At lower protein concentrations, individual current spikes are resolved as characteristic single-entity events in resistive pulse sensing. Those transient events are potential-dependent characterized by the peak amplitude, duration and area/charges. Statistical analysis reveals both translocation of protein oligomers and their transformation or further aggregation. This study represents the first step toward elucidating valuable insights into the dynamics of protein translocation and aggregation in heavy water and demonstrates the potential of using nanopores in the detection and characterization of dynamic phase transitions at single-event levels.</div></div>","PeriodicalId":426,"journal":{"name":"Sensors and Actuators Reports","volume":"9 ","pages":"Article 100281"},"PeriodicalIF":6.5,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}