Sensors And Actuators. A, Physical[JOURNAL]
Sun
84 papers
Recent Progress in Blood Flow Sensing.
Chen R, Liang J, Li M … +1 more , Meng E
Sens Actuators A Phys · 2025 Jun · PMID 40213382 · Full text
Blood plays a central role in the maintenance of the human body, and monitoring its flow rate, either invasively or non-invasively, in different parts of the circulatory is essential in the diagnosis and treatment of pat...
Blood plays a central role in the maintenance of the human body, and monitoring its flow rate, either invasively or non-invasively, in different parts of the circulatory is essential in the diagnosis and treatment of patients and for advancing biomedical research. This review examines the history and challenges of blood flow sensing and highlights the current state-of-the art blood flowmeters alongside the emerging tools poised to realize continuous and real-time monitoring. The clinical requirements for designing blood flow sensors are considered, including where the sensors are interfaced and their signal transduction mechanisms. Finally, the existing technological gaps are discussed and potential pathways to allow for further optimization are explored. Continued innovations in the several hundred years of evolution of blood flow sensing technology are poised to provide more timely interventions related to maintaining proper blood flow for improving patient care and outcomes.
An electromagnetic indirect-driving scanning mirror for wide-field coaxial LiDAR applications.
Li S, Wang D, Song D … +1 more , Zou J
Sens Actuators A Phys · 2024 Dec · PMID 40191072 · Full text
This paper reports an electromagnetic indirect-driving scanning mirror with an enlarged mirror plate ( × ) supported by high-strength polymer hinges for wide-field coaxial LiDAR (Light Detection and Ranging) applicatio...
This paper reports an electromagnetic indirect-driving scanning mirror with an enlarged mirror plate ( × ) supported by high-strength polymer hinges for wide-field coaxial LiDAR (Light Detection and Ranging) applications. An indirect-driving mechanism was developed to achieve large tilting angle through mechanical amplification, while maintaining a relatively high resonance frequency of the enlarged mirror plate. A prototype mirror was designed, fabricated, and tested. A Hall scan position sensor was integrated to monitor the pose of the mirror in real time. The testing results show a coupled resonance frequency of 54.9 with an optical tilting angle of ± °, corresponding to a field of view (FoV) of 12 °. A wide-field coaxial LiDAR system was also built based on the indirect-driving scanning mirror, and 2D imaging was demonstrated.
Antenna-Driven Optical Fiber-Based Acousto-Optic Modulation Devices: Electro-Mechanical Model and Experimental Validation.
Bradley LW, Yaras YS, Degertekin FL
Sens Actuators A Phys · 2025 Jun · PMID 40124104 · Full text
Acousto-optic modulation (AOM)-based sensors offer distinct advantages compared to their electrical counterparts. The electromagnetic immunity of optical fibers makes AOMs ideal for applications like radio frequency (RF)...
Acousto-optic modulation (AOM)-based sensors offer distinct advantages compared to their electrical counterparts. The electromagnetic immunity of optical fibers makes AOMs ideal for applications like radio frequency (RF) field measurement inside the bore of a magnetic resonance imaging (MRI) scanner without interfering with the RF environment. These RF field sensors utilize antennae coupled with a radially poled, coaxial piezoelectric transducer over an optical Fiber-Bragg Grating (FBG). The design and optimization of these sensors require a complete electromechanical model of the fiber-transducer composite structure. This study presents an electromechanical equivalent circuit model for antenna-coupled, fiber-based AOMs, toward the determination of the electromechanical frequency response of this type of AOM-based sensor. The transducer model is validated against experimental data on a Zinc Oxide (ZnO)-based acousto-optic phase modulator in 1-800 MHz range, as well as a piezocomposite-based FBG-AOM sensor in the 1-100 MHz range. The antenna-coupled model is validated experimentally utilizing an N-turn loop antenna-coupled sensor for H-field measurements up to 100 MHz. The results also show the utility of sensitive, broadband optical FBG measurements for characterizing piezoelectric materials with high losses, which prevents accurate electrical characterization. The developed and validated model can be beneficial for design optimization of AF-AOM based sensors for different applications.
A water-immersible scanning mirror with hybrid polymer and elastomer hinges for high-speed and wide-field 3D ultrasound imaging.
Li S, Dong Z, Song P … +1 more , Zou J
Sens Actuators A Phys · 2024 Mar · PMID 39380786 · Full text
This paper reports a new water-immersible single-axis scanning mirror using hybrid polymer and elastomer hinges to achieve both high scanning resonance frequencies and large tilting angles for high-speed and wide-field 3...
This paper reports a new water-immersible single-axis scanning mirror using hybrid polymer and elastomer hinges to achieve both high scanning resonance frequencies and large tilting angles for high-speed and wide-field 3D ultrasound imaging. To demonstrate the concept, a prototype scanning mirror is designed, fabricated, and characterized. The fast- and slow-scanning were achieved by integrating stiff BoPET (biaxially oriented polyethylene terephthalate) and soft elastomer PDMS (Polydimethylsiloxane) hinges, respectively. The testing results have shown a resonance frequency of 270 for the BoPET hinges and a resonance frequency of 10 for the PDMS hinges when the scanning mirror was immersed in water. 3D ultrasound imaging is demonstrated by combining the fast- and slow-scanning together to provide both an augmented field of view (FoV) and high local imaging volume rate.
Advancements and Applications of Micro and Nanostructured Capacitive Sensors: A Review.
Sakthivelpathi V, Li T, Qian Z … +3 more , Lee C, Taylor Z, Chung JH
Sens Actuators A Phys · 2024 Oct · PMID 39129941 · Full text
Capacitors are essential components in modern electrical systems, functioning primarily to store electrical charges and regulate current flow. Capacitive sensors, developed in the 20th century, have become crucial in var...
Capacitors are essential components in modern electrical systems, functioning primarily to store electrical charges and regulate current flow. Capacitive sensors, developed in the 20th century, have become crucial in various applications, including touchscreens and smart devices, due to their ability to detect both metallic and non-metallic objects with high sensitivity and low energy consumption. The advancement of microelectromechanical systems (MEMS) and nanotechnology has significantly enhanced the capabilities of capacitive sensors, leading to unprecedented sensitivity, dynamic range, and cost-effectiveness. These sensors are integral to modern devices, enabling precise measurements of proximity, pressure, strain, and other parameters. This review provides a comprehensive overview of the development, fabrication, and integration of micro and nanostructured capacitive sensors. In terms of an electric field, the working and detection principles are discussed with analytical equations and our numerical results. The focus extends to novel fabrication methods using advanced materials to enhance sensitivities for various parameters, such as proximity, force, pressure, strain, temperature, humidity, and liquid sensing. Their applications are demonstrated in wearable devices, human-machine interfaces, biomedical sensing, health monitoring, robotics control, industrial monitoring, and molecular detection. By consolidating existing research, this review offers insights into the advancements and future directions of capacitive sensor technology.
Environmental noise reduction for tunable resistive pulse sensing of extracellular vesicles.
Ejjigu N, Abdelgadir K, Flaten Z … +3 more , Hoff C, Li CZ, Sun D
Sens Actuators A Phys · 2022 Oct · PMID 37273787 · Full text
Extracellular vesicles (EVs) bearing biomolecules from parental cells can represent a novel source of disease biomarkers and are under intensive study for their clinical potential. Tunable resistive pulse sensing (TRPS)...
Extracellular vesicles (EVs) bearing biomolecules from parental cells can represent a novel source of disease biomarkers and are under intensive study for their clinical potential. Tunable resistive pulse sensing (TRPS) quantifies the magnitude of a small ionic resistive pulse current to determine the size, concentration, and zeta potential of EVs. Environmental noise is a common limiting factor that affects the precision of sensing devices. TRPS is particularly vulnerable to environmental noise, including both mechanical and electrical. The upper detection limit of the TRPS relies on the physical size of the elastomeric tunable nanopore. The lower limit relies on the electrical signal-to-noise ratio. Guided by simulation, we designed an external device to suppress environmental noise for TRPS measurement. Both mechanical and electrical environmental noise reductions were observed after using the shield. The study also validated the noise reduction function of the shield by quantifying EVs from different cell origins. Detection of EVs smaller than 200 nm was improved by using the shield; which was reported challenging for conventional quantification methods. The study highlighted a feasible approach to solve environmental noise challenges for TRPS based EV quantification.
Physics-based Models for photonic thermometers.
Ahmed Z
Sens Actuators A Phys · 2022 Dec · PMID 37152107 · Full text
Resistance thermometry, meticulously developed over the last century, provides a time-tested method for taking temperature measurements. However, fundamental limits to resistance-based approaches along with a desire to r...
Resistance thermometry, meticulously developed over the last century, provides a time-tested method for taking temperature measurements. However, fundamental limits to resistance-based approaches along with a desire to reduce the cost of sensor ownership, increase sensor stability and meet the growing needs of emerging economy has produced considerable interest in developing photonic temperature sensors. In this study we utilize Della-Corte-Varshni treatment for thermo-optic coefficient to derive models for temperature-wavelength relationships in silicon ring resonators and Fiber Bragg gratings. Model evaluation is carried out using a Bayesian criteria that selects models for superior out-of-sample predictive accuracy whilst minimizing model complexity. Our work presents physics-based framework for photonic thermometry reference functions, putting constraints on model complexity and parameter bounds, pointing the way towards a reference function that can be utilized for future standardization and inter-comparison of photonic thermometers.
Hysteresis Compensation in Temperature Response of Fiber Bragg Grating Thermometers Using Dynamic Regression.
Ahmed Z
Sens Actuators A Phys · 2022 Nov · PMID 36590444 · Full text
In recent years there has been considerable interest in using photonic thermometers such as Fiber Bragg grating (FBG) and silicon ring resonators as an alternative technology to resistance-based legacy thermometers. Alth...
In recent years there has been considerable interest in using photonic thermometers such as Fiber Bragg grating (FBG) and silicon ring resonators as an alternative technology to resistance-based legacy thermometers. Although FBG thermometers have been commercially available for decades their metrological performance remains poorly understood, hindered in part by complex behavior at elevated temperatures. In this study we systematically examine the temporal evolution of the temperature response of 14 sensors that were repeatedly cycled between 233 K and 393 K. Data exploration and modelling indicate the need to account for serial-correlation in model selection. Utilizing the coupled-mode theory treatment of FBG to guide feature selection we evaluate various calibration models. Our results indicates that a dynamic regression model can effectively reduce measurement uncertainty due to hysteresis by up to ≈ 70% .
Batteryless wireless magnetostrictive FeCo/Ni clad plate for human coronavirus 229E detection.
Neyama D, Fakhruddin SMB, Inoue KY … +8 more , Kurita H, Osana S, Miyamoto N, Tayama T, Chiba D, Watanabe M, Shiku H, Narita F
Sens Actuators A Phys · 2023 Jan · PMID 36447950 · Full text
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been garnered increasing for its rapid worldwide spread. Each country had implemented city-wide lockdowns and immigration regulations to prevent the spread...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been garnered increasing for its rapid worldwide spread. Each country had implemented city-wide lockdowns and immigration regulations to prevent the spread of the infection, resulting in severe economic consequences. Materials and technologies that monitor environmental conditions and wirelessly communicate such information to people are thus gaining considerable attention as a countermeasure. This study investigated the dynamic characteristics of batteryless magnetostrictive alloys for energy harvesting to detect human coronavirus 229E (HCoV-229E). Light and thin magnetostrictive Fe-Co/Ni clad plate with rectification, direct current (DC) voltage storage capacitor, and wireless information transmission circuits were developed for this purpose. The power consumption was reduced by improving the energy storage circuit, and the magnetostrictive clad plate under bending vibration stored a DC voltage of 1.9 V and wirelessly transmitted a signal to a personal computer once every 5 min and 10 s under bias magnetic fields of 0 and 10 mT, respectively. Then, on the clad plate surface, a novel CD13 biorecognition layer was immobilized using a self-assembled monolayer of -COOH groups, thus forming an amide bond with -NH groups for the detection of HCoV-229E. A bending vibration test demonstrated the resonance frequency changes because of HCoV-229E binding. The fluorescence signal demonstrated that HCoV-229E could be successfully detected. Thus, because HCoV-229E changed the dynamic characteristics of this plate, the CD13-modified magnetostrictive clad plate could detect HCoV-229E from the interval of wireless communication time. Therefore, a monitoring system that transmits/detects the presence of human coronavirus without batteries will be realized soon.
Single-arm diagnostic electrocardiography with printed graphene on wearable textiles.
Ozturk O, Golparvar A, Acar G … +2 more , Guler S, Yapici MK
Sens Actuators A Phys · 2023 Jan · PMID 36447633 · Full text
Stimulated by the COVID-19 outbreak, the global healthcare industry better acknowledges the necessity of innovating novel methods for remote healthcare monitoring and treating patients outside clinics. Here we report the...
Stimulated by the COVID-19 outbreak, the global healthcare industry better acknowledges the necessity of innovating novel methods for remote healthcare monitoring and treating patients outside clinics. Here we report the development of two different types of graphene textile electrodes differentiated by the employed fabrication techniques (i.e., dip-coating and spray printing) and successful demonstration of ergonomic and truly wearable, single-arm diagnostic electrocardiography (SADE) using only 3 electrodes positioned on only 1 arm. The performance of the printed graphene e-textile wearable systems were benchmarked against the "gold standard" silver/silver chloride (Ag/AgCl) "wet" electrodes; achieving excellent correlation up to ∼ 96% and ∼ 98% in ECG recordings (15 s duration) acquired with graphene textiles fabricated by dip-coating and spray printing techniques, respectively. In addition, we successfully implemented automatic detection of heartrate of 8 volunteers (mean value: 74.4 bpm) during 5 min of static and dynamic daily activities and benchmarked their recordings with a standard fingertip photoplethysmography (PPG) device. Heart rate variability (HRV) was calculated, and the root means successive square difference (rMMSD) metric was 30 ms during 5 min of recording. Other cardiac parameters such as R-R interval, QRS complex duration, S-T segment duration, and T-wave duration were also detected and compared to typical chest ECG values.
Physics-Based Circuit Modeling of the Impedance Characteristics of a Smart Hydrogel-Actuated Bending Sensor.
Ahmed B, Reiche CF, Solzbacher F … +2 more , Magda J, Körner J
Sens Actuators A Phys · 2022 Nov · PMID 39310816 · Full text
Smart hydrogels are stimuli-responsive polymers which exhibit a volume-phase transition in response to external influences. This makes them promising candidates for sensing elements, especially in a biomedical context du...
Smart hydrogels are stimuli-responsive polymers which exhibit a volume-phase transition in response to external influences. This makes them promising candidates for sensing elements, especially in a biomedical context due to their easily achievable biocompatibility. The main challenge in harnessing the smart polymer's potential for sensor applications lies in a reliable transduction of the swelling change into an electrical signal. A novel platform approach is based on a bending sensor where the smart hydrogel acts as an actuator on a thin film with embedded metal traces. Mechanical deformation due to the hydrogel volume change alters the traces' electric impedance. However, besides deformation, the medium surrounding the sensor structure will also affect the impedance. For sensor design it is therefore crucial to understand the complex interdependencies between electric sensor properties, influences of the surrounding medium and mechanical deformation. Here, an electric circuit model is presented which considers all these contributions through a minimum number of lumped elements and is strictly based on physical considerations. By employing measured impedance spectra from an experimental sensor implementation subjected to different surrounding media and mechanical deformation, the validity of the simplified model is demonstrated. A detailed analysis and discussion give insights into the determination of the different model parameters and how external influences can clearly be attributed to specific circuit elements. This work provides a general approach for deducing minimalistic but strictly physics-based circuit models which can still adequately replicate the actual behavior of such types of impedance-based bending sensors.
Capacitive Eye Tracker Made of Fractured Carbon Nanotube-Paper Composites for Wearable Applications.
Sakthivelpathi V, Qian Z, Li T … +4 more , Ahn S, Dichiara AB, Soetedjo R, Chung JH
Sens Actuators A Phys · 2022 Sep · PMID 40012761 · Full text
The uniqueness of eyes, facial geometry, and gaze direction makes eye tracking a very challenging technological pursuit. Although camera-based eye-tracking systems are popular, the obtrusiveness of their bulky equipment...
The uniqueness of eyes, facial geometry, and gaze direction makes eye tracking a very challenging technological pursuit. Although camera-based eye-tracking systems are popular, the obtrusiveness of their bulky equipment along with their high computational cost and power consumption is considered problematic for wearable applications. Noncontact gaze monitoring using capacitive sensing technique has been attempted but failed due to low sensitivity and parasitic capacitance. Here, we study the interaction between a novel capacitive sensor and eye movement for wearable eye-tracking. The capacitive sensors are made of a pair of asymmetric electrodes; one comprising carbon nanotube-paper composite fibers (CPC) and the other being a rectangular metal electrode. The interaction between the asymmetric sensor and a spherical object mimicking an eyeball is analyzed numerically. Using a face simulator, both single- and differential capacitive measurements are characterized with respect to proximity, geometry, and human body charge. Using a prototype eye tracker, multiple sensor locations are studied to determine the optimal configurations. The capacitive responses to vertical and horizontal gaze directions are analyzed in comparison to those of a commercial eye tracking system. The performance is demonstrated for sensitive eye-movement tracking, closed-eye monitoring, and human-machine interface. This research has important implications for the development of capacitive, wearable eye trackers, which can facilitate fields of human-machine interface, cognitive monitoring, neuroscience research, and rehabilitation.
Design and Evaluation of In-Plane Silicon Microneedles Fabricated with Post-CMOS Compatible Processes.
Al Mamun A, Sueoka B, Allison N … +2 more , Huang Y, Zhao F
Sens Actuators A Phys · 2022 Apr · PMID 35573145 · Full text
In this paper, a comprehensive study was carried out on in-plane silicon (Si) microneedles, a useful tool for transdermal drug delivery and sample collection. Microneedles with eleven designs were investigated by post-co...
In this paper, a comprehensive study was carried out on in-plane silicon (Si) microneedles, a useful tool for transdermal drug delivery and sample collection. Microneedles with eleven designs were investigated by post-complementary metal-oxide-semiconductor (CMOS) compatible microfabrication processes and characterized via pricking tests by insertion in chicken breast flesh. Mechanical strength of all designs were also evaluated by theoretical calculation and finite element modeling (FEM) for bending and buckling analysis. To efficiently improve the sharpness and insertion, the wedge-shaped needle tips with thickness determined by Si wafer thickness were sharpened by a wet chemical etching process. Insertion forces recorded from pricking tests and bending and buckling from theoretical calculation and FEM analysis before and after etching were compared. The results showed that the insertion force, free bending force and the maximum buckling force were all reduced and the maximum bending stress were improved after tip sharpening. Furthermore, the buckling safety factor of all eleven designs was great than 1 and the maximum bending stress was less than the fracture strength of Si, indicating that our in-plane Si microneedles are robust enough for insertion into human skin.
A biomimetic skin phantom for characterizing wearable electrodes in the low-frequency regime.
Goyal K, Borkholder DA, Day SW
Sens Actuators A Phys · 2022 Jun · PMID 35493959 · Full text
Advances in the integration of wearable devices in our daily life have led to the development of new electrode designs for biopotential monitoring. Historically, the development and testing of wearable electrodes for the...
Advances in the integration of wearable devices in our daily life have led to the development of new electrode designs for biopotential monitoring. Historically, the development and testing of wearable electrodes for the acquisition of biopotential signals has been empirical, relying on experiments on human volunteers. However, the lack of explicit control on human variables, the intra-, and inter-subject variability complicates the understanding of the performance of these wearable electrodes. Herein, phantom mimicking the electrical properties of the skin in the low-frequency range (1 Hz-1000 Hz), which has the potential to be used as a platform for controlled benchtop experiments for testing electrode functionality, is demonstrated. The fabricated phantom comprises two layers representing the deeper tissues and stratum corneum. The lower layer of the phantom mimicking deeper tissues was realized using polyvinyl alcohol cryogel (PVA-c) prepared with 0.9% W/W saline solution by a freeze-thaw technique. The properties of the upper layer representing the stratum corneum were simulated using a 100μm thick layer fabricated by spin-coating a mixture of polydimethylsiloxane (PDMS), 2.5% W/W carbon black (CB) for conductance, and 40% W/W barium titanate (BaTiO) as a dielectric. The hydration of the stratum corneum was modeled in a controlled way by varying porosity of the phantom's upper layer. Impedance spectroscopy measurements were carried out to investigate the electrical performance of the fabricated phantom and validated against the impedance response obtained across a physiological skin impedance range of five human subjects. The results indicated that the Bode plot depicting the impedance response obtained on the phantom was found to lie in the human skin range. Moreover, it was observed that the change of porosity provides control over the hydration and the phantom can be tuned as per the skin ranges among different individuals. Also, the phantom was able to mimic the impact of dry and hydrated skin on a simulated ECG signal in the time domain. The developed skin phantom is affordable, fairly easy to manufacture, stable over time, and can be used as a platform for benchtop testing of new electrode designs.
A review of peristaltic micropumps.
Forouzandeh F, Alfadhel A, Arevalo A … +1 more , Borkholder DA
Sens Actuators A Phys · 2021 Aug · PMID 35386682 · Full text
This report presents a review of progress on peristaltic micropumps since their emergence, which have been widely used in many research fields from biology to aeronautics. This paper summarizes different techniques that...
This report presents a review of progress on peristaltic micropumps since their emergence, which have been widely used in many research fields from biology to aeronautics. This paper summarizes different techniques that have been used to mimic this elegant physiological transport mechanism that is commonly found in nature. The analysis provides definitions of peristaltic micropumps and their different features, distinguishing them from other mechanical micropumps. Important parameters in peristalsis are presented, such as the operating frequency, stroke volume, and various actuation sequences, along with introducing design rules and analysis for optimizing actuation sequences. Actuation methods such as piezoelectric, motor, pneumatic, electrostatic, and thermal are discussed with their advantages and disadvantages for application in peristaltic micropumps. This review evaluates research efforts over the past 30 years with comparison of key features and outputs, and suggestions for future development. The analysis provides a starting point for researchers designing peristaltic micropumps for a broad range of applications.
Acoustics at the nanoscale (nanoacoustics): A comprehensive literature review.: Part II: Nanoacoustics for biomedical imaging and therapy.
Peng C, Chen M, Spicer JB … +1 more , Jiang X
Sens Actuators A Phys · 2021 Dec · PMID 34937992 · Full text
In the past decade, acoustics at the nanoscale (i.e., nanoacoustics) has evolved rapidly with continuous and substantial expansion of capabilities and refinement of techniques. Motivated by research innovations in the la...
In the past decade, acoustics at the nanoscale (i.e., nanoacoustics) has evolved rapidly with continuous and substantial expansion of capabilities and refinement of techniques. Motivated by research innovations in the last decade, for the first time, recent advancements of acoustics-associated nanomaterials/nanostructures and nanodevices for different applications are outlined in this comprehensive review, which is written in two parts. As part II of this two-part review, this paper concentrates on nanoacoustics in biomedical imaging and therapy applications, including molecular ultrasound imaging, photoacoustic imaging, ultrasound-mediated drug delivery and therapy, and photoacoustic drug delivery and therapy. Firstly, the recent developments of nanosized ultrasound and photoacoustic contrast agents as well as their various imaging applications are examined. Secondly, different types of nanomaterials/nanostructures as nanocarriers for ultrasound and photoacoustic therapies are discussed. Finally, a discussion of challenges and future research directions are provided for nanoacoustics in medical imaging and therapy.
Acoustics at the nanoscale (nanoacoustics): A comprehensive literature review.: Part I: Materials, devices and selected applications.
Peng C, Chen M, Spicer JB … +1 more , Jiang X
Sens Actuators A Phys · 2021 Dec · PMID 34937991 · Full text
In the past decade, acoustics at the nanoscale (i.e., nanoacoustics) has evolved rapidly with continuous and substantial expansion of capabilities and refinement of techniques. Motivated by research innovations in the la...
In the past decade, acoustics at the nanoscale (i.e., nanoacoustics) has evolved rapidly with continuous and substantial expansion of capabilities and refinement of techniques. Motivated by research innovations in the last decade, for the first time, recent advancements of acoustics-associated nanomaterials/nanostructures and nanodevices for different applications are outlined in this comprehensive review, which is written in two parts. As part I of this two part review, firstly, active and passive nanomaterials and nanostructures for acoustics are presented. Following that, representative applications of nanoacoustics including material property characterization, nanomaterial/nanostructure manipulation, and sensing, are discussed in detail. Finally, a summary is presented with point of views on the current challenges and potential solutions in this burgeoning field.
Compliant Underwater Manipulator with Integrated Tactile Sensor for Nonlinear Force Feedback Control of an SMA Actuation System.
Lin M, Vatani M, Choi JW … +2 more , Dilibal S, Engeberg ED
Sens Actuators A Phys · 2020 Nov · PMID 34629752 · Full text
Design, sensing, and control of underwater gripping systems remain challenges for soft robotic manipulators. Our study investigates these critical issues by designing a shape memory alloy (SMA) actuation system for a sof...
Design, sensing, and control of underwater gripping systems remain challenges for soft robotic manipulators. Our study investigates these critical issues by designing a shape memory alloy (SMA) actuation system for a soft robotic finger with a directly 3D-printed stretchable skin-like tactile sensor. SMA actuators were thermomechanically trained to assume a curved finger-like shape when Joule heated, and the flexible multi-layered tactile sensor was directly 3D-printed onto the surface of the fingertip. A nonlinear controller was developed to enable precise fingertip force control using feedback from the compliant tactile sensor. Underwater experiments were conducted using closed-loop force feedback from the directly 3D-printed tactile sensor with the SMA actuators, showing satisfactory force tracking ability. Furthermore, a 3D finite element model was developed to more deeply understand the shape memory thermal-fluidic-structural multi-physics simulation of the manipulator underwater. An application for human control via electromyogram (EMG) signals also demonstrated an intuitive way for a person to operate the submerged robotic finger. Together, these results suggested that the soft robotic finger could be used to carefully manipulate fragile objects underwater.
Deep Learning-Enabled Resolution-Enhancement in Mini- and Regular Microscopy for Biomedical Imaging.
Dai M, Xiao G, Fiondella L … +2 more , Shao M, Zhang YS
Sens Actuators A Phys · 2021 Nov · PMID 34393376 · Full text
Artificial intelligence algorithms that aid mini-microscope imaging are attractive for numerous applications. In this paper, we optimize artificial intelligence techniques to provide clear, and natural biomedical imaging...
Artificial intelligence algorithms that aid mini-microscope imaging are attractive for numerous applications. In this paper, we optimize artificial intelligence techniques to provide clear, and natural biomedical imaging. We demonstrate that a deep learning-enabled super-resolution method can significantly enhance the spatial resolution of mini-microscopy and regular-microscopy. This data-driven approach trains a generative adversarial network to transform low-resolution images into super-resolved ones. Mini-microscopic images and regular-microscopic images acquired with different optical microscopes under various magnifications are collected as our experimental benchmark datasets. The only input to this generative-adversarial-network-based method are images from the datasets down-sampled by the Bicubic interpolation. We use independent test set to evaluate this deep learning approach with other deep learning-based algorithms through qualitative and quantitative comparisons. To clearly present the improvements achieved by this generative-adversarial-network-based method, we zoom into the local features to explore and highlight the qualitative differences. We also employ the peak signal-to-noise ratio and the structural similarity, to quantitatively compare alternative super-resolution methods. The quantitative results illustrate that super-resolution images obtained from our approach with interpolation parameter =0.25 more closely match those of the original high-resolution images than to those obtained by any of the alternative state-of-the-art method. These results are significant for fields that use microscopy tools, such as biomedical imaging of engineered living systems. We also utilize this generative adversarial network-based algorithm to optimize the resolution of biomedical specimen images and then generate three-dimensional reconstruction, so as to enhance the ability of three-dimensional imaging throughout the entire volumes for spatial-temporal analyses of specimen structures.
A micromachined force sensing apparatus and method for human engineered cardiac tissue and induced pluripotent stem cell characterization.
Turnbull IC, Zhu W, Stillitano F … +2 more , Chien CC, Gaitas A
Sens Actuators A Phys · 2021 Nov · PMID 34305317 · Full text
Induced pluripotent stem cell derived-cardiomyocytes (iPSC-CMs) have great potential for cell therapy, drug assessment, and for understanding the pathophysiology and genetic underpinnings of cardiac diseases. Contraction...
Induced pluripotent stem cell derived-cardiomyocytes (iPSC-CMs) have great potential for cell therapy, drug assessment, and for understanding the pathophysiology and genetic underpinnings of cardiac diseases. Contraction forces are one of the most important characteristics of cardiac function and are predictors of healthy and diseased states. Cantilever techniques, such as atomic force microscopy, measure the vertical force of a single cell, while systems designed to more closely resemble the physical heart function, such as engineered cardiac tissue held by end-posts, measure the axial force. One important question is how do these two force measurements correlate? By establishing a correlation of the axial and vertical force, we will be one step closer in being able to use single cell iPSC-CMs as models. A novel micromachined sensor for measuring force contractions of engineered tissue has been developed. Using this novel sensor, a correlation between axial force and vertical force is experimentally established. This finding supports the use of vertical measurements as an alternative to tissue measurements.
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