Sens Actuators A Phys
· 2021 Aug · PMID 33840899
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Undoubtedly, the coronavirus disease 2019 (COVID-19) has received the greatest concern with a global impact, and this situation will continue for a long period of time. Looking back in history, airborne transimission dis...Undoubtedly, the coronavirus disease 2019 (COVID-19) has received the greatest concern with a global impact, and this situation will continue for a long period of time. Looking back in history, airborne transimission diseases have caused huge casualties several times. COVID-19 as a typical airborne disease caught our attention and reminded us of the importance of preventing such diseases. Therefore, this study focuses on finding a new way to guard against the spread of these diseases such as COVID-19. This paper studies the dynamic electromechanical response of metal-core piezoelectric fiber/epoxy matrix composites, designed as mass load sensors for virus detection, by numerical modelling. The dynamic electromechanical response is simulated by applying an alternating current (AC) electric field to make the composite vibrate. Furthermore, both concentrated and distributed loads are considered to assess the sensitivity of the biosensor during modelling of the combination of both biomarker and viruses. The design parameters of this sensor, such as the resonant frequency, the position and size of the biomarker, will be studied and optimized as the key values to determine the sensitivity of detection. The novelty of this work is to propose functional composites that can detect the viruses from changes of the output voltage instead of the resonant frequency change using piezoelectric sensor and piezoelectric actuator. The contribution of this detection method will significantly shorten the detection time as it avoids fast Fourier transform (FFT) or discrete Fourier transform (DFT). The outcome of this research offers a reliable numerical model to optimize the design of the proposed biosensor for virus detection, which will contribute to the production of high-performance piezoelectric biosensors in the future.
Sens Actuators A Phys
· 2020 · PMID 33487884
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Two different LIGA electrodeposited nickel alloys displayed distinct fracture modes after meso-scale tensile testing. The Ni-Co alloy failed in a ductile manner, while the Ni-Fe alloy failed in a more brittle-appearing m...Two different LIGA electrodeposited nickel alloys displayed distinct fracture modes after meso-scale tensile testing. The Ni-Co alloy failed in a ductile manner, while the Ni-Fe alloy failed in a more brittle-appearing manner. Various factors affecting the fracture are discussed; it was determined that the fracture mode did not depend upon the strain rate but did depend upon the sample geometry. The difference in the microstructure is likely the cause of the difference in fracture mode, as the Ni-Co alloy is fine-grained, while the Ni-Fe alloy is nano-grained and likely failed by a creep-like mechanism.
Sens Actuators A Phys
· 2021 Jan · PMID 33380777
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We developed flexible electrostatic transducers with both a single element and a 2×2 array format to actuate at a precise displacement across a range of loads with a control circuitry and algorithm. The transducer, compo...We developed flexible electrostatic transducers with both a single element and a 2×2 array format to actuate at a precise displacement across a range of loads with a control circuitry and algorithm. The transducer, composed of a moving buckled film with an integrated electrode and a rigid electrode, can be used to simultaneously generate and sense displacements. A circuit and computer program were designed to demonstrate displacement control and quantify the sensing precision of the transducer. Specifically, we applied a range of voltage and load conditions to the transducer and array and measured the displacement while under loading through capacitive sensing. The change in capacitance was linear with respect to the area of the electrode in contact and matched theoretical predictions when described as a function of the displacement. The transducer was loaded with weights in the range of 5-27 mN and capacitance-driving voltage graphs were obtained. An 8Hz driving frequency was used to move the transducer, while a 10.8kHz signal was used to sense the capacitance. These were used to build a predictive model to correct for sensed load to maintain a average displacement. It was found that a transducer of dimensions 10mm × 40mm was able to maintain displacement under loads of 5-27mN, while a matrix composed of 10mm × 20mm transducers was able to maintain displacement under loads of 2.5-11mN. In general, the detection thresholds of human skin can range between 5-20mN of force and 2-20um of displacement for frequencies between 1Hz and 250Hz, so these values are in line with what is needed to build a functional haptic wearable device. The present work provides a method to quantitatively measure and control a new type of flexible transducer for a variety of haptic applications.
Jin C, Hao N, Xu Z
… +6 more, Trase I, Nie Y, Dong L, Closson A, Chen Z, Zhang JXJ
Sens Actuators A Phys
· 2020 Apr · PMID 33380776
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Piezoelectric nanomaterial-polymer composites represent a unique paradigm for making flexible energy harvesting and sensing devices with enhanced devices' performance. In this work, we studied various metal doped ZnO nan...Piezoelectric nanomaterial-polymer composites represent a unique paradigm for making flexible energy harvesting and sensing devices with enhanced devices' performance. In this work, we studied various metal doped ZnO nanostructures, fabricated and characterized ZnO nanoparticle-PVDF composite thin film, and demonstrated both enhanced energy generation and motion sensing capabilities. Specifically, a series of flexible piezoelectric nanogenerators (PENGs) were designed based on these piezoelectric composite thin films. The voltage output from cobalt (Co), sodium (Na), silver (Ag), and lithium (Li) doped ZnO-PVDF composite as well as pure ZnO-PVDF samples were individually studied and compared. Under the same experimental conditions, the Li-ZnO based device produces the largest peak-to-peak voltage (3.43 Vpp) which is about 9 times of that of the pure ZnO based device, where Co-ZnO, Na-ZnO and Ag-ZnO are 1.2, 4.9 and 5.4 times, respectively. In addition, the effect of doping ratio of Li-ZnO is studied, and we found that 5% is the best doping ratio in terms of output voltage. Finally, we demonstrated that the energy harvested by the device from finger tapping at ~2 Hz can charge a capacitor with a large output power density of 0.45 W/cm and light up an ultraviolet (UV) light-emitting diode (LED). We also showed the device as a flexible wearable motion sensor, where different hand gestures were detected by the device with distinctive output voltage amplitudes and patterns.
Gunasekaran S, Thangaraju D, Marnadu R
… +6 more, Chandrasekaran J, Shkir M, Durairajan A, Valente MA, Alshaharanig T, Elango M
Sens Actuators A Phys
· 2021 Jan · PMID 33071460
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Development of photo detectors based on different semiconducting materials with high performance has been in progress in recent past, however, there is a lot of difficulties in developing the more effective photo detecto...Development of photo detectors based on different semiconducting materials with high performance has been in progress in recent past, however, there is a lot of difficulties in developing the more effective photo detectors-based devices with high responsivity, detectivity and quantum efficiency. Hence, we have synthesized pure CuS and CuO@CuS core-shell heterostructure based photo detectors with high performance by simple and cost-effective two-step chemical co-precipitation method. The phase purity of CuS and CuO@CuS composite was observed by XRD analysis and the result were verified with Raman spectroscopy studies. Sphere like morphology of pure CuS and core-shell structure formation of CuO@CuS are observed with scanning and transmission electron microscopes. The presence of expected elements has been confirmed with EDX elemental mapping. Light harvesting photodiodes were fabricated by using n-type silicon substrate through drop cost method. Photo sensitive parameters of fabricated diodes were analyzed by I-V characteristics. The p-CuO@CuS (1:1)/n-Si diode owned a maximum photosensitivity (Ps) ∼ 7.76 10 %, photoresponsivity (R) ∼ 798.61 mA/W, external quantum efficiency ( )∼309.66 % and specific detectivity (D*) ∼ 8.19 × 10 Jones when compared to p-CuS/n-Si diode. The obtained results revealed that the core/shell heterostructure of CuO@CuS is the most appropriate for photo detection.
Sens Actuators A Phys
· 2020 Jan · PMID 32863582
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This paper presents rapid photothermal actuation of light-addressable, arrayed hydrogel columns in a macroporous silicon membrane. Au nanorods are incorporated into thermo-responsive p-NIPAAm hydrogel to utilize surface...This paper presents rapid photothermal actuation of light-addressable, arrayed hydrogel columns in a macroporous silicon membrane. Au nanorods are incorporated into thermo-responsive p-NIPAAm hydrogel to utilize surface plasmon-induced local heating by near-infrared light. By measuring optical transmission through the fabricated membrane structure with Au nanorod embedded hydrogel, we have demonstrated that photothermal actuation of hydrogel can be done in two-dimensional, pixel-like configuration with high spatial and temporal resolutions. Benefiting from the hydrogel volume confinement within micron-sized pores, we have achieved sub-second response time of hydrogel photothermal actuation and its repeatable photothermal actuation on highly localized illuminated area. Considering that each hydrogel column is confined within each pore and different wavelength of light can be used to induce photothermal actuation of hydrogel's deswelling characteristics by modifying physical dimensions of Au nanorods, it has a potential for optically-addressable, multiplexed drug release systems with rapid response time.
Sens Actuators A Phys
· 2020 Aug · PMID 32661455
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Noninvasive measurement of liver iron concentration (LIC) is clinically important. Yet, at the present time, it can only be achieved with SQUID technology. However, SQUID based BLS suffers high costs and cumbersome cryog...Noninvasive measurement of liver iron concentration (LIC) is clinically important. Yet, at the present time, it can only be achieved with SQUID technology. However, SQUID based BLS suffers high costs and cumbersome cryogenic requirements that prevent SQUID BLS from being adopted by clinical applications. Recently, we demonstrated that a single channel ME sensor with piezo-single crystals could detect LIC from only 3cc of mouse liver tissue without any magnetic field shielding. The results demonstrated not only the sensitivity of ME sensor system for LIC but also the feasibility for mapping LIC profiles spatially. This investigation further developed ME sensor arrays, exploiting the compact size and room temperature operation. A Dual-Channel 1-D ME sensor array along the vertical, Z-direction, was developed and shown to be sensitive to the skin-liver distance change which can be utilized to calibrate and eliminate the inter-subject variability of the LIC measurement due to skin-liver distance. With phantom having spatially dependent iron concentrations, the 1-D ME sensor array was capable of mapping the one-dimensional profile of the iron concentration in the horizontal X- and Y-directions. The results of the prototype sensor devices show the feasibility of an array ME-sensors for imaging iron profile.
Sens Actuators A Phys
· 2020 Sep · PMID 32647405
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The use of a metallic adhesion layer between plasmonic-active nanostructures and a solid supported is known to dampen the plasmonic response. To overcome this problem, organic adhesion layers have been introduced, which...The use of a metallic adhesion layer between plasmonic-active nanostructures and a solid supported is known to dampen the plasmonic response. To overcome this problem, organic adhesion layers have been introduced, which in turn can undermine the stability of the film. Moreover, both types of layers limit the regeneration of the nanostructures for multiple uses. Here we report a quick and simple approach to prepare intermediate adhesion layer-free binding of nanostructured films of gold on silicon wafers. The approach involves scratching and etching of the silicon wafer before sputter coating with a thin layer of Au. The plasmonic-active nanostructures were then prepared on this thin Au film using electrochemical deposition. As-prepared plasmonic-active nanostructured thin films of gold (PANTF-Au) are easy to handle, physically robust, and can be regenerated. The bulk refractive index sensitivity of PANTF-Au is 150 nm/RIU with the figure of merit 1.4, and with a plasmonic field-decay length of 27 nm. We further used these thin films to study interactions between lectin and glycoprotein inside a flow cell as well as on a microplate made of PANTF-Au. The PANTF-Au can be easily integrated with electrochemical devices and microfluidics, which can help to pave the way toward the development of ideal optical-electrochemical point-of-care biosensors.
Carpenter CW, Ting Melissa Tan S, Keef C
… +6 more, Skelil K, Malinao M, Rodriquez D, Alkhadra MA, Ramírez J, Lipomi DJ
Sens Actuators A Phys
· 2019 Apr · PMID 31777429
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The word "haptics" refers to technologies designed to stimulate the tactile and kinesthetic senses. Kinesthesia-the sense of motion-is triggered by imposing forces upon the joints, tendons, and muscles to recreate the ge...The word "haptics" refers to technologies designed to stimulate the tactile and kinesthetic senses. Kinesthesia-the sense of motion-is triggered by imposing forces upon the joints, tendons, and muscles to recreate the geometry and stiffness of objects, as may be useful in physical therapy or virtual reality. Here, we introduce a form of kinesthetic feedback by manipulating the mechanical properties of spandex impregnated with a thermoplastic polymer. Heating or cooling this textile-thermoplastic composite just above or below its glass transition temperature ( ) dramatically changes its mechanical properties (corresponding to a decrease in storage modulus from 36 MPa to 0.55 MPa). In the form of a glove, the composite can also be healed after inadvertent overextension in its stiffened state by heating it above its . When fitted with thermoelectric devices for active heating and cooling, the flexible or stiffened state of a glove can be perceived by human subjects. As an example of a human-machine interface, the glove is used to control a robotic finger. When the robotic finger makes contact with a wall, a signal is sent to thermoelectric devices in the glove to cool (stiffen the finger) and thus provide kinesthetic feedback to the user.
Sens Actuators A Phys
· 2019 May · PMID 31327893
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Lead zirconate titanate (PZT) has wide applications in microelectromechanical systems (MEMS) due to its large piezoelectric coefficients. However, there exist serious issues during PZT wet etching even with multiple etch...Lead zirconate titanate (PZT) has wide applications in microelectromechanical systems (MEMS) due to its large piezoelectric coefficients. However, there exist serious issues during PZT wet etching even with multiple etching steps, such as residues on etching fronts and large undercut. In this paper, a one-step residue-free wet etching process of ceramic PZT is developed with fluoroboric acid. In this work, the design of experiments (DOE) method is employed to minimize undercut and residues without sacrificing etching rate. The acid concentration, temperature, and agitation are the process parameters considered in the DOE. Through DOE analysis of the experimental data, an optimal recipe is identified as the volume ratio of HBF:HO=1:10 at 23 °C. This new PZT etching recipe leads to a high etching rate (1.54 μm/min) with no observable residues and a small undercut (0.78:1) as well as a high selectivity over the photoresist (900:1). This etching recipe can be used for making various piezoelectric transducers.
Sens Actuators A Phys
· 2018 Jan · PMID 29255340
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Resistance thermometry provides a time-tested method for taking temperature measurements that has been painstakingly developed over the last century. However, fundamental limits to resistance-based approaches along with...Resistance thermometry provides a time-tested method for taking temperature measurements that has been painstakingly developed over the last century. However, fundamental limits to resistance-based approaches along with a desire to reduce the cost of sensor ownership and increase sensor stability has produced considerable interest in developing photonic temperature sensors. Here we demonstrate that silicon photonic crystal cavity-based thermometers can measure temperature with uncertainities of 175 mK ( = 1), where uncertainties are dominated by ageing effects originating from the hysteresis in the device packaging materials. Our results, a ≈ 4-fold improvement over recent developments, clearly demonstate the rapid progress of silicon photonic sensors in replacing legacy devices.
Sens Actuators A Phys
· 2017 Sep · PMID 29151675
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A theoretical maximum achievable signal to noise ratio (SNR) for piezoelectric microphones is identified as a function of only microphone volume irrespective of architecture and construction details. For a given piezoele...A theoretical maximum achievable signal to noise ratio (SNR) for piezoelectric microphones is identified as a function of only microphone volume irrespective of architecture and construction details. For a given piezoelectric material, microphone SNR can be reduced to an expression containing only a dimensionless coupling coefficient and microphone volume. For a given material, the coupling coefficient has a theoretical upper bound defined by the most favorable deformation geometry. The ability to identify a theoretical maximum SNR as a function of only microphone size is surprising considering the numerous design variables and infinite design freedom afforded in the microphone design stage.
Jibril L, Ramírez J, Zaretski AV
… +1 more, Lipomi DJ
Sens Actuators A Phys
· 2017 Aug · PMID 28860679
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This article describes the fabrication of single-nanowire strain sensors by thin sectioning of gold films with an ultramicrotome-i.e., "nanoskiving." The nanowire sensors are transferred to various substrates from the wa...This article describes the fabrication of single-nanowire strain sensors by thin sectioning of gold films with an ultramicrotome-i.e., "nanoskiving." The nanowire sensors are transferred to various substrates from the water bath on which they float after sectioning. The electrical response of these single nanowires to mechanical strain is investigated, with the lowest detectable strain determined to be 1.6 × 10 with a repeatable response to strains as high as 7 × 10. The sensors are shown to have an enhanced sensitivity with a gauge factor of 3.1 on average, but as high as 9.5 in the low strain regime (ε ~ 1 × 10). Conventional thin films of gold of the same height as the nanowires are used as controls, and are unable to detect those same strains. The practicality of this sensor is investigated by transferring a single nanowire to polyimide tape, and placing the sensor on the wrist to monitor the pulse pressure waveform from the radial artery. The nanowires are fabricated with simple tools and require no lithography. Moreover, the sensors can be "manufactured" efficiently, as each consecutive section of the film is a quasi copy of the previous nanowire. The simple fabrication of these nanowires, along with the compatibility with flexible substrates, offers possibilities in developing new kinds of devices for biomedical applications and structural health monitoring.
Apigo DJ, Bartholomew PL, Russell T
… +3 more, Kanwal A, Farrow RC, Thomas GA
Sens Actuators A Phys
· 2016 Nov · PMID 28533631
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A device, with MEMS sensors at its core, has been fabricated and tested for measuring low fluid pressure and slow flow rates. The motivation was to measure clinically relevant ranges of slow-moving fluids in living syste...A device, with MEMS sensors at its core, has been fabricated and tested for measuring low fluid pressure and slow flow rates. The motivation was to measure clinically relevant ranges of slow-moving fluids in living systems, such as the cerebrospinal fluid in the brain. For potential clinical utility, the device can be read transcutaneously by inductive coupling to MEMS capacitive sensors in circuits with resonance frequencies in the MHz range. Signal shifts for flow rates in the range of 0-42 mL/h and differential pressure levels between 0.1 and 2 kPa have been measured, because the sensitivity in the capacitance gap measurement is about 1 Å. The sensors have been used successfully to monitor simulated cerebrospinal fluid dynamics. The device does not utilize any internal power, since it is powered externally via the inductive coupling.
Sens Actuators A Phys
· 2016 Mar · PMID 26855476
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We present an implantable micropump with a miniature form factor and completely wireless operation that enables chronic drug administration intended for evaluation and development of cancer therapies in freely moving sma...We present an implantable micropump with a miniature form factor and completely wireless operation that enables chronic drug administration intended for evaluation and development of cancer therapies in freely moving small research animals such as rodents. The low power electrolysis actuator avoids the need for heavy implantable batteries. The infusion system features a class E inductive powering system that provides on-demand activation of the pump as well as remote adjustment of the delivery regimen without animal handling. Micropump performance was demonstrated using a model anti-cancer application in which daily doses of 30 μL were supplied for several weeks with less than 6% variation in flow rate within a single pump and less than 8% variation across different pumps. Pumping under different back pressure, viscosity, and temperature conditions were investigated; parameters were chosen so as to mimic conditions. In benchtop tests under simulated conditions, micropumps provided consistent and reliable performance over a period of 30 days with less than 4% flow rate variation. The demonstrated prototype has potential to provide a practical solution for remote chronic administration of drugs to ambulatory small animals for research as well as drug discovery and development applications.
Raj R, Lakshmanan S, Apigo D
… +6 more, Kanwal A, Liu S, Russell T, Madsen JR, Thomas GA, Farrow RC
Sens Actuators A Phys
· 2015 Oct · PMID 26543321
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A flow sensor has been fabricated and tested that is capable of measuring the slow flow characteristic of the cerebrospinal fluid in the range from less than 4 mL/h to above 100 mL/h. This sensor is suitable for long-ter...A flow sensor has been fabricated and tested that is capable of measuring the slow flow characteristic of the cerebrospinal fluid in the range from less than 4 mL/h to above 100 mL/h. This sensor is suitable for long-term implantation because it uses a wireless external spectrometer to measure passive subcutaneous components. The sensors are pressure-sensitive capacitors, in the range of 5 pF with an air gap at atmospheric pressure. Each capacitor is in series with an inductor to provide a resonant frequency that varies with flow rate. At constant flow, the system is steady with drift <0.3 mL/h over a month. At variable flow rate, , the resonant frequency, , which is in the 200-400 MHz range, follows a second order polynomial with respect to . For this sensor system the uncertainty in measuring is 30 kHz which corresponds to a sensitivity in measuring flow of = 0.6 mL/hr. Pressures up to 20 cm HO relative to ambient pressure were also measured. An implantable twin capacitor system is proposed that can measure flow, which is fully compensated for all hydrostatic pressures. For twin capacitors, other sources of systematic variation within clinical range, such as temperature and ambient pressure, are smaller than our sensitivity and we delineate a calibration method that should maintain clinically useful accuracy over long times.
Sens Actuators A Phys
· 2015 Sep · PMID 26347583
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Scanning fiber tips provides the most convenient way for forward-viewing fiber-optic microendoscopy. In this paper, a distal fiber scanning method based on a large-displacement MEMS actuator is presented. A single-mode f...Scanning fiber tips provides the most convenient way for forward-viewing fiber-optic microendoscopy. In this paper, a distal fiber scanning method based on a large-displacement MEMS actuator is presented. A single-mode fiber is glued on the micro-platform of an electrothermal MEMS stage to realize large range non-resonantscanning. The micro-platform has a large piston scan range of up to 800 µm at only 6V. The tip deflection of the fiber can be further amplified by placing the MEMS stage at a proper location along the fiber. A quasi-static model of the fiber-MEMS assembly has been developed and validated experimentally. The frequency response has also been studied and measured. A fiber tip deflection of up to 1650 µm for the 45 mm-long movable fiber portion has been achieved when the MEMS electrothermal stage was placed 25 mm away from the free end. The electrothermally-actuated MEMS stage shows a great potential for forward viewing fiber scanning and optical applications.
Mayrhofer PM, Euchner H, Bittner A
… +1 more, Schmid U
Sens Actuators A Phys
· 2015 Feb · PMID 26109748
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Piezoelectric scandium aluminium nitride (Sc Al N) thin films offer a large potential for the application in micro electromechanical systems, as advantageous properties of pure AlN thin films are maintained, but combine...Piezoelectric scandium aluminium nitride (Sc Al N) thin films offer a large potential for the application in micro electromechanical systems, as advantageous properties of pure AlN thin films are maintained, but combined with an increased piezoelectric actuation and sensing potential. Sc Al N thin films with = 27% have been prepared by DC reactive magnetron sputtering to find optimized deposition parameters to maximize the piezoelectric constants and . For the accurate and simultaneous measurement of these constants Laser Doppler Vibrometry has been applied and compared to finite element (FEM) simulations. The electrode design has been optimized to rotational symmetric structures enabling a 180° phase shifted excitation, so that a straight-forward comparison of experimental displacement curves with those obtained from FEM is feasible.
Yoon S, Williams J, Kang BJ
… +6 more, Yoon C, Cabrera-Munoz N, Jeong JS, Lee SG, Shung KK, Kim HH
Sens Actuators A Phys
· 2015 Jun · PMID 25914443
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A transducer with an angled and focused aperture for intravascular ultrasound imaging has been developed. The acoustic stack for the angled-focused transducer was made of PMN-PT single crystal with one matching layer, on...A transducer with an angled and focused aperture for intravascular ultrasound imaging has been developed. The acoustic stack for the angled-focused transducer was made of PMN-PT single crystal with one matching layer, one protective coating layer, and a highly damped backing layer. It was then press-focused to a desired focal length and inserted into a thin needle housing with an angled tip. A transducer with an angled and unfocused aperture was also made, following the same fabrication procedure, to compare the performance of the two transducers. The focused and unfocused transducers were tested to measure their center frequencies, bandwidths, and spatial resolutions. Lateral resolution of the angled-focused transducer (AFT) improved more than two times compared to that of the angled-unfocused transducer (AUT). A tissue-mimicking phantom in water and a rabbit aorta tissue sample in rabbit blood were scanned using AFT and AUT. Imaging with AFT offered improved contrast, over imaging with AUT, of the tissue-mimicking phantom and the rabbit aorta tissue sample by 23 dB and 8 dB, respectively. The results show that AFT has strong potential to provide morphological and pathological information of coronary arteries with high resolution and high contrast.
Zhu J, Shang J, Olsen T
… +3 more, Liu K, Brenner D, Lin Q
Sens Actuators A Phys
· 2014 Aug · PMID 25821347
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Controlled manipulation, such as isolation, positioning and trapping of cells, is important in basic biological research and clinical diagnostics. Micro/nanotechnologies have been enabling more effective and efficient ce...Controlled manipulation, such as isolation, positioning and trapping of cells, is important in basic biological research and clinical diagnostics. Micro/nanotechnologies have been enabling more effective and efficient cell trapping than possible with conventional platforms. Currently available micro/nanoscale methods for cell trapping, however, still lack flexibility in precisely controlling the number of trapped cells. We exploited the large compliance of elastomers to create an array of cell-trapping microstructures, whose dimensions can be mechanically modulated by inducing uniformly distributed strain via application of external force on the chip. The device consists of two elastomer polydimethylsiloxane (PDMS) sheets, one of which bears dam-like, cup-shaped geometries to physically capture cells. The mechanical modulation is used to tune the characteristics of cell trapping to capture a predetermined number of cells, from single cells to multiple cells. Thus, enhanced utility and flexibility for practical applications can be attained, as demonstrated by tunable trapping of MCF-7 cells, a human breast cancer cell line.