Ziqiang Chen , Wentao Wang , Shudong Yu , Baixuan Gao , Zeping Deng
{"title":"Bioinspired fabrication of micro- and nanostructured flexible sensors from surface architecture to interface engineering: A review","authors":"Ziqiang Chen , Wentao Wang , Shudong Yu , Baixuan Gao , Zeping Deng","doi":"10.1016/j.sna.2025.116931","DOIUrl":"10.1016/j.sna.2025.116931","url":null,"abstract":"<div><div>Drawing inspiration from nature by exploring bionic micro-nano structures found in animals and plants offers an effective strategy for enhancing the sensing performance of flexible sensors in emerging applications. This paper reviews recent advances in bio-inspired micro-nano structures of flexible sensors, spanning surface architecture to interface engineering. Firstly, two primary directions of animal-inspired designs, including spiders, scorpions, and tree frogs, and plant-inspired designs, including flytraps, mimosas, and nepenthes, are introduced to establish the relationship between micro-nano structures and sensing properties. Secondly, the cutting-edge progress of bio-inspired geometries in flexible pressure sensors, such as pyramids and hemispheres, are reviewed to enhance the force-sensitive signals in flexible sensor. Thirdly, the efficient implement of bionic structures including cracks, wrinkles, serpentines and helices, as well as interface engineering is then emphasized, with a focus on improving sensing performance under complex deformations in practical scenarios. Finally, the key challenges and future prospects in the manufacturing of bio-inspired micro- and nanostructured flexible sensors are discussed, illustrating the great potential of this method in fields such as health monitoring and human-machine interfaces.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116931"},"PeriodicalIF":4.9,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144772747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chlorophyll fluorescence sensing for smart agriculture","authors":"Longgang Ma , Maoyuan Yin , Xujun Chen, Zhengzhong Wan, Ruihua Zhang, Zhencan Yang, Xinqing Xiao","doi":"10.1016/j.sna.2025.116930","DOIUrl":"10.1016/j.sna.2025.116930","url":null,"abstract":"<div><div>Chlorophyll fluorescence sensing technology, with its increasing application in smart agriculture, is particularly impactful in agricultural cultivation, aquaculture, and food monitoring. This technology reflects the physiological state of plants and environmental changes in real-time, based on the fluorescence response in photosynthesis of plant leaves. With high sensitivity, real-time monitoring, and non-destructive detection, the technology becomes an important monitoring tool in smart agriculture. In agricultural cultivation, chlorophyll fluorescence sensing technology can assess the efficiency of crop photosynthesis, providing real-time data support for precision agriculture. Furthermore, this technology contributes to detecting potential problems, such as water stress and pests and diseases to optimize agricultural management. In aquaculture, the technology can be used for water quality monitoring and assessment of algal growth status, promoting the fine management of the aquaculture environment. For food monitoring, chlorophyll fluorescence sensors can realize real-time detection of food quality and safety by analyzing the fluorescence characteristics of plant components. This review analyzes the application of chlorophyll fluorescence sensing technology in smart agriculture, discusses its technical advantages, application limitations, and challenges, and elaborates on its potential to promote sustainable agricultural development.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116930"},"PeriodicalIF":4.9,"publicationDate":"2025-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Design and characterization of temperature sensing layer in Joule-heated micro- and nano-actuators","authors":"Nengqi Zhang , Jian Zhang","doi":"10.1016/j.sna.2025.116927","DOIUrl":"10.1016/j.sna.2025.116927","url":null,"abstract":"<div><div>The Joule-heated micro- and nano-actuator is composed of a functional layer and a silicon layer. Under the influence of Joule heating, \"these two materials undergo differential expansion, leading to mechanical bending and shape changes in the composite structure. Therefore, in the study of micro- and nano-actuators based on the Joule heating effect, temperature monitoring and control are crucial for optimizing actuator performance and ensuring its reliability. In this study, the theoretical temperature distribution of the micro- and nano-actuator is derived to verify the feasibility of adding a platinum layer as a temperature sensing layer on the original actuator structure. By monitoring the resistance changes of this layer, the temperature distribution of the beam structure can be measured. The results indicate that for every 100 ℃ increase in the actuator's maximum temperature, its resistance increases by approximately 5.3 %. Experimental validation is conducted using a bridge structure with a silicon base layer and a platinum top layer, with beam lengths ranging from 10.4 μm to 24.6 μm. The experimental data show that from environment temperature to 220 ℃, the temperature sensing layer can effectively and timely measure the temperature magnitude and distribution of the beam. However, as the current further increases and the beam temperature exceeds 220 ℃, the resistance of the silicon layer undergoes a sudden change, rendering the sensing results no longer applicable. Additionally, under high-power conditions, the boundary conditions differ significantly from those in normal circumstances, causing the calculated temperature values to be lower than the actual temperature values. The research results demonstrate that preparing a resistive temperature sensing layer on a Joule-heating-type micro- and nano-actuator to measure its temperature is feasible. However, for higher temperature conditions, the reliability and accuracy of this method require further optimization.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116927"},"PeriodicalIF":4.9,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Naorem Kheljit Singh , Borish Moirangthem , Loushambam Herojit Singh
{"title":"Enhanced resistive switching performance in WO3/NiO bilayer thin film","authors":"Naorem Kheljit Singh , Borish Moirangthem , Loushambam Herojit Singh","doi":"10.1016/j.sna.2025.116924","DOIUrl":"10.1016/j.sna.2025.116924","url":null,"abstract":"<div><div>In this article, we investigate the resistive switching behavior of a bilayer heterostructure comprising n-type WO₃ and p-type NiO thin films, demonstrating its potential as a promising candidate for future nonvolatile RRAM devices. The rationale for employing the WO₃/NiO bilayer lies in the complementary electrical and defect properties of the both the oxides where, NiO offers stable switching characteristics due to its p-type conductivity and defect-rich structure, while WO₃ enhances filament formation through its high oxygen vacancy mobility. The n–p heterojunction formed between the two layers introduces an internal electric field that assists in controlled ion migration, leading to improved switching stability and performance. From the electrical characterization, we have got abnormal resistive switching nature with endurance of 100 testing cycles, and resistive window of ∼ 325 along with10<sup>4</sup> s of data retention. From the linear fitting of the electrical hysteresis, it also found that the resistive switching initiates with Schottky emission in LRS, and switching to SCLC conduction along with direct tunneling in HRS with voltage sweep changes. From the finding of our investigation, the deposited bilayer heterostructure n-WO<sub>3</sub>/p-NiO thin film device is a future potential RRAM nonvolatile device.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116924"},"PeriodicalIF":4.9,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olga I. Guliy , Boris D. Zaitsev , Sergey A. Staroverov , Roman D. Vyrshchikov , Sergey V. Kozlov , Evgeniy S. Kozlov , Lev A. Dykman , Vinoj Gopalakrishnan , Irina A. Borodina
{"title":"Immunodetection of heat shock protein–containing cancer cells with a compact acoustic sensor","authors":"Olga I. Guliy , Boris D. Zaitsev , Sergey A. Staroverov , Roman D. Vyrshchikov , Sergey V. Kozlov , Evgeniy S. Kozlov , Lev A. Dykman , Vinoj Gopalakrishnan , Irina A. Borodina","doi":"10.1016/j.sna.2025.116923","DOIUrl":"10.1016/j.sna.2025.116923","url":null,"abstract":"<div><div>The steady increase in cancer incidence and mortality has attracted research attention to the design of new methods for early cancer detection. The detection of heat shock protein (HSP)–containing cells in actual samples is of great importance and is a starting point for a new direction in early cancer diagnostics. We used an acoustic biosensor and HSP-specific antibodies as the sensing element to detect HSP-containing cells from spontaneously diseased cats with confirmed adenocarcinoma. The minimal detection limit was 10<sup>2</sup> cells/mL. The biosensor permitted <em>in vitro</em> studies in primary cancer screening. Our approach may become the basis for the further development of a full-fledged diagnostic screening system for early cancer detection. It ensures a rapid and accurate determination of HSP-containing cells and may help to determine disease progression or treatment efficacy.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116923"},"PeriodicalIF":4.9,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144772805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A three-axis nanopositioner based on near-field acoustic levitation and electromagnetic actuation","authors":"K.S. Vikrant, Prosanto Biswas, S.O. Reza Moheimani","doi":"10.1016/j.sna.2025.116894","DOIUrl":"10.1016/j.sna.2025.116894","url":null,"abstract":"<div><div>Near-field acoustic levitation (NFAL) enables nanometer-scale positioning resolution and bandwidth exceeding several hundred hertz specifically along the vertical (Z) direction, owing to its high acoustic stiffness and squeeze film damping. However, its application to horizontal (XY) positioning is limited by significantly lower acoustic stiffness and insufficient damping in horizontal directions, resulting in reduced resolution and bandwidth. Moreover, NFAL-based positioning systems typically lack multi-axis actuation capabilities due to challenges in generating multi-directional acoustic forces. This work presents a hybrid positioning approach that overcomes the mentioned limitations by integrating NFAL with electromagnetic actuation. A planar magnetic platform is acoustically levitated, while a coplanar current-carrying coil provides horizontal trapping stiffness more than three orders of magnitude higher than that achievable with acoustic forces alone. Additionally, the coil generates three-dimensional electromagnetic forces, enabling multi-axis positioning capability. Eddy currents induced in a thin copper sheet integrated with the coil enhance horizontal damping by 52 times. We experimentally demonstrate precise 3-axis linear motion with a root mean square (RMS) positioning resolution better than 20 nm along all axes. The system achieves an in-plane motion range of 1.42 mm with a bandwidth of 16 Hz and a Z-axis motion range of 40 <span><math><mi>μ</mi></math></span>m with a positioning bandwidth of 171 Hz.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116894"},"PeriodicalIF":4.9,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144772802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Renqing Wen , Guozheng Yan , Ding Han , Shuai Kuang , Pingping Jiang , Zhiwu Wang
{"title":"Design and optimization of wireless power transfer system for capsule robot based on electromagnetic and thermal safety limitations","authors":"Renqing Wen , Guozheng Yan , Ding Han , Shuai Kuang , Pingping Jiang , Zhiwu Wang","doi":"10.1016/j.sna.2025.116905","DOIUrl":"10.1016/j.sna.2025.116905","url":null,"abstract":"<div><div>Capsule robot (CR) is an emerging device for diagnosing and treating digestive disorders, primarily relies on electromagnetic induction for power transfer. However, concerns have been raised regarding the potential structural and biological heating caused by high-frequency magnetic field, which could damage surrounding tissues. This paper introduces an optimization approach for the winding parameters of a 1D receiving coil (RC) in a novel 3D transmitting system. Initially, finite element simulations are employed to access the uniformity of magnetic field and identify the maximum safe current. Then, experiments in both DC and AC environments are conducted to identify a suitable RC. As a result, we select a 16-strand, 104-turn RC that meets both electromagnetic and thermal safety. When integrated into an inchworm-style CR, the coil maintains a maximum temperature of 41.8 °C after 10 min of continuous motion, with a safe transmitting current of 3.61 A at the center point. The experimental results demonstrate that the proposed wireless power transfer (WPT) system can reliably and safely deliver sufficient energy to CR. Multidimensional transmitting system effectively reduces the size of RC, and solves the problem of the traditional 3D RC occupies too much space. The heat generation of the CR can be effectively controlled by the selected appropriate winding parameters, which verifies the potential for further in vivo experiments.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116905"},"PeriodicalIF":4.9,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144766811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fuyin Zheng, Yue Li, Ping Huang, Long Ma, Chuang Wang, Shi Bai, Lijian Yang
{"title":"Extremely sensitive bias field-based ACSM: A new approach to improve pipeline structural integrity monitoring","authors":"Fuyin Zheng, Yue Li, Ping Huang, Long Ma, Chuang Wang, Shi Bai, Lijian Yang","doi":"10.1016/j.sna.2025.116919","DOIUrl":"10.1016/j.sna.2025.116919","url":null,"abstract":"<div><div>Stress detection is widely recognized as a critical and challenging scientific issue in the inspection of long-distance oil and gas pipelines. Currently, alternating current stress magnetization (ACSM) is commonly employed for identifying and evaluating stress in ferromagnetic materials. However, its limited stress response sensitivity and unclear detection mechanisms hinder further technological advancement. In this study, we propose an alternating electromagnetic stress detection method based on a extremely sensitive bias field. By integrating the thermodynamically derived magneto-mechanical coupling relationship of ferromagnetic materials with Maxwell's equations, we establish a force-magnetic coupling model in the stress concentration zones of pipelines under electromagnetic excitation. Furthermore, we analyze the spatial distribution trend of magnetic flux leakage in stress concentration regions under an alternating electromagnetic field, modulated by a weak constant bias magnetic field. Our findings reveal that the weak bias field significantly influences the electromagnetic stress detection signals in ferromagnetic materials. Systematic experiments demonstrate that the stress response sensitivity initially increases and then decreases with the strength of the weak constant bias field. Notably, the presence of an optimal bias field—termed the extreme sensitive bias field—maximizes sensitivity, which reaches 0.67 mV/MPa under the experimental conditions of this study, representing an enhancement of approximately 11.67 times. This research introduces a novel method for improving stress response sensitivity and the identification and evaluation of stress-induced damage, offering significant scientific value for the early detection, prevention, and assessment of pipeline damage.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116919"},"PeriodicalIF":4.9,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144757574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kai Fukushi , Shinya Yoshida , Xuanmeng Qi , Shuji Tanaka
{"title":"Investigation of optimal composition ratio of Sm-doped Pb(Mg1/3,Nb2/3)O3-PbTiO3 monocrystalline thin film with large piezoelectric performance","authors":"Kai Fukushi , Shinya Yoshida , Xuanmeng Qi , Shuji Tanaka","doi":"10.1016/j.sna.2025.116921","DOIUrl":"10.1016/j.sna.2025.116921","url":null,"abstract":"<div><div>We investigated the composition dependence of the piezoelectric properties of Sm-doped Pb(Mg<sub>1/3</sub>,Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3</sub> (Sm-PMN-PT) monocrystalline thin films as a candidate of transducer thin films for Micro Electro Mechanical Systems (MEMS). Sm-PMN-PT thin films with various PMN/PT ratio were sputter-deposited on Si wafers covered with a buffer layer. The composition ratio was tuned by changing the PMN/PT ratio in the sputtering target. All thin films had excellent crystallinities, few pyrochlore phases, and (100)/(001) preferential orientations. The piezoelectric constants of |<em>e</em><sub>31,f</sub>| and |<span><math><msub><mrow><mi>d</mi></mrow><mrow><mn>31</mn><mo>,</mo><mi>eff</mi></mrow></msub></math></span>| were evaluated by actuating a piezoelectric unimorph cantilevers. As a result, the thin film prepared by the sputtering target with PMN/PT ratio of 50/50 showed |<em>e</em><sub>31,f</sub>| as large as 24 C/m<sup>2</sup>. |<span><math><msub><mrow><mi>d</mi></mrow><mrow><mn>31</mn><mo>,</mo><mi>eff</mi></mrow></msub></math></span>| reaches a large value of ∼400 pm/V if the elastic compliance is assumed to be same as those of a PMN-PT single crystal. We believe that this thin film has a potential to break the performance limitation of piezo MEMS actuators.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116921"},"PeriodicalIF":4.9,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Noninvasive blood glucose monitoring technology based on PSO optimized CNN-BiGRU-attention neural network model and photoplethysmography","authors":"Liwen Xiong, Shengpeng Wan, Congxiang Chen, Junsong Yu","doi":"10.1016/j.sna.2025.116914","DOIUrl":"10.1016/j.sna.2025.116914","url":null,"abstract":"<div><div>This paper studies non-invasive blood glucose monitoring technology based on PPG in the near-infrared band. By extracting 12 key features from the PPG signal and adjusting the parameters of the CBA (CNN-BiGRU-Attention) model using the Particle Swarm Optimization (PSO) algorithm, we achieve accurate prediction of BGL. The results show that the mean absolute relative difference (MARD) of the model on the test set is 7.10 % with a confidence interval of [5.8 %, 8.4 %], the mean absolute error (MAE) is 0.469 mmol/L, and the root mean squared error (RMSE) is 0.578 mmol/L. In the Clarke error grid analysis (EGA), the proportion of Zone A is 96.4 %, while Zone B accounts for 3.6 %. The results show that based on the algorithmic model proposed in this paper, PPG can be used as an effective non-invasive blood glucose monitoring method for daily monitoring of blood glucose monitoring in diabetic patients.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"394 ","pages":"Article 116914"},"PeriodicalIF":4.9,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144750417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}