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Prof. Keat Ghee Ong
Michigan Technological University, Department of Biomedical Engineering, Houghton, United States

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0 Biomedical Instrumentation
0 Regenerative Medicine
0 Wireless Sensors
0 implantable sensors
0 magnetoelastic materials

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magnetoelastic materials
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implantable sensors

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Communication to the editor
Published: 18 January 2021 in Biotechnology and Bioengineering
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Magnetoelastic (ME) sensors, which can be remotely activated via magnetic fields, are an excellent choice for wireless monitoring of biological parameters due to their ability to be scaled into different sizes and have their surface functionalized for chemical or biological sensing. In this study, we present the application of a commercially available ME material (Metglas 2826 MB) to develop a sensor system that can monitor the attachment of anchorage‐dependent mammalian cells in 2D in vitro cell cultures. Results obtained with the developed sensors and detection system correlated with microscopic image analysis of cell quantification, which showed a linear relationship between the sensor response and attached fibroblast cells on the sensor surface. It was also revealed that the developed ME sensor system is capable of providing temporal profiles of cell growth corresponding to different stages of cell attachment and proliferation in real time.

ACS Style

Sudhanshu Shekhar; Salil S. Karipott; Robert E. Guldberg; Keat Ghee Ong. Magnetoelastic sensors for real‐time tracking of cell growth. Biotechnology and Bioengineering 2021, 118, 2380 -2385.

AMA Style

Sudhanshu Shekhar, Salil S. Karipott, Robert E. Guldberg, Keat Ghee Ong. Magnetoelastic sensors for real‐time tracking of cell growth. Biotechnology and Bioengineering. 2021; 118 (6):2380-2385.

Chicago/Turabian Style

Sudhanshu Shekhar; Salil S. Karipott; Robert E. Guldberg; Keat Ghee Ong. 2021. "Magnetoelastic sensors for real‐time tracking of cell growth." Biotechnology and Bioengineering 118, no. 6: 2380-2385.

Review
Published: 16 August 2020 in Sensors
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Wireless technologies are incorporated in implantable devices since at least the 1950s. With remote data collection and control of implantable devices, these wireless technologies help researchers and clinicians to better understand diseases and to improve medical treatments. Today, wireless technologies are still more commonly used for research, with limited applications in a number of clinical implantable devices. Recent development and standardization of wireless technologies present a good opportunity for their wider use in other types of implantable devices, which will significantly improve the outcomes of many diseases or injuries. This review briefly describes some common wireless technologies and modern advancements, as well as their strengths and suitability for use in implantable medical devices. The applications of these wireless technologies in treatments of orthopedic and cardiovascular injuries and disorders are described. This review then concludes with a discussion on the technical challenges and potential solutions of implementing wireless technologies in implantable devices.

ACS Style

Bradley D. Nelson; Salil Sidharthan Karipott; Yvonne Wang; Keat Ghee Ong. Wireless Technologies for Implantable Devices. Sensors 2020, 20, 4604 .

AMA Style

Bradley D. Nelson, Salil Sidharthan Karipott, Yvonne Wang, Keat Ghee Ong. Wireless Technologies for Implantable Devices. Sensors. 2020; 20 (16):4604.

Chicago/Turabian Style

Bradley D. Nelson; Salil Sidharthan Karipott; Yvonne Wang; Keat Ghee Ong. 2020. "Wireless Technologies for Implantable Devices." Sensors 20, no. 16: 4604.

Review
Published: 14 August 2020 in Sensors
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In high concentrations, ionic species can be toxic in the body, catalyzing unwanted bioreactions, inhibiting enzymes, generating free radicals, in addition to having been associated with diseases like Alzheimer’s and cancer. Although ionic species are ubiquitous in the environment in trace amounts, high concentrations of these metals are often found within industrial and agricultural waste runoff. Therefore, it remains a global interest to develop technologies capable of quickly and accurately detecting trace levels of ionic species, particularly in aqueous environments that naturally contain other competing/inhibiting ions. Herein, we provide an overview of the technologies that have been developed, including the general theory, design, and benefits/challenges associated with ion-selective electrode technologies (carrier-doped membranes, carbon-based varieties, enzyme inhibition electrodes). Notable variations of these electrodes will be highlighted, and a brief overview of associated electrochemical techniques will be given.

ACS Style

William S. Skinner; Keat Ghee Ong. Modern Electrode Technologies for Ion and Molecule Sensing. Sensors 2020, 20, 4568 .

AMA Style

William S. Skinner, Keat Ghee Ong. Modern Electrode Technologies for Ion and Molecule Sensing. Sensors. 2020; 20 (16):4568.

Chicago/Turabian Style

William S. Skinner; Keat Ghee Ong. 2020. "Modern Electrode Technologies for Ion and Molecule Sensing." Sensors 20, no. 16: 4568.

Preprint content
Published: 29 July 2020
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Mechanical loading of bone defects through rehabilitation is a promising therapeutic approach to stimulate repair and reduce the risk of non-union; however, little is known about how therapeutic mechanical stimuli modulate early stages of repair before mineralized bone formation. In a previous study, we established an osteogenic mechanical loading protocol using early ambulatory rehabilitation and a compliant, load-sharing fixator in a rat model of BMP-2 mediated bone defect repair. The objective of this study was to investigate the early effects of osteogenic loading on cytokine expression, tissue composition, and angiogenesis during the first 3 weeks of repair in this model. Using a wireless implantable strain sensor for local measurements of mechanical boundary conditions, finite element simulations showed that osteogenic mechanical loading increased mean compressive strain in defect soft tissue during rehabilitative ambulation at 1 week (load-sharing: -1.54 +/- 0.17% vs. load-shielded: -0.76 +/- 0.06%), and that strain was amplified in remaining soft tissue regions at 3 weeks as mineralization progressed (load-sharing: -1.89 +/- 0.35% vs. load-shielded: -1.38 +/- 0.35%). Multivariate analysis of multiplex cytokine arrays revealed that loading significantly altered cytokine expression profiles in the defect tissue at 2 weeks compared to load-shielded defects. Specifically, loading reduced VEGF and increased CXCL5 (LIX) levels. Subsequently, vascular volume in loaded defects was reduced relative to load-shielded defects but similar to intact bone at 3 weeks. Endochondral bone repair was also observed histologically in loaded defects only at 3 weeks. Together, these results demonstrate that moderate ambulatory strains previously shown to stimulate functional bone regeneration significantly alter early angiogenic and cytokine signaling and may promote endochondral ossification in large segmental bone defects.

ACS Style

Brett S Klosterhoff; Casey E. Vantucci; Jarred Kaiser; Keat Ghee Ong; Levi B Wood; Jeffrey A. Weiss; Robert E. Guldberg; Nick J. Willett. Effects of osteogenic ambulatory mechanical stimulation on early stages of BMP-2 mediated bone repair. 2020, 1 .

AMA Style

Brett S Klosterhoff, Casey E. Vantucci, Jarred Kaiser, Keat Ghee Ong, Levi B Wood, Jeffrey A. Weiss, Robert E. Guldberg, Nick J. Willett. Effects of osteogenic ambulatory mechanical stimulation on early stages of BMP-2 mediated bone repair. . 2020; ():1.

Chicago/Turabian Style

Brett S Klosterhoff; Casey E. Vantucci; Jarred Kaiser; Keat Ghee Ong; Levi B Wood; Jeffrey A. Weiss; Robert E. Guldberg; Nick J. Willett. 2020. "Effects of osteogenic ambulatory mechanical stimulation on early stages of BMP-2 mediated bone repair." , no. : 1.

Journal article
Published: 25 June 2020 in Measurement Science and Technology
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ACS Style

Bradley D Nelson; Salil Sidharthan Karipott; Robert E Guldberg; Keat Ghee Ong. A piezoelectric bone fixation plate for in vivo application and monitoring of mechanical loading during fracture healing. Measurement Science and Technology 2020, 31, 095703 .

AMA Style

Bradley D Nelson, Salil Sidharthan Karipott, Robert E Guldberg, Keat Ghee Ong. A piezoelectric bone fixation plate for in vivo application and monitoring of mechanical loading during fracture healing. Measurement Science and Technology. 2020; 31 (9):095703.

Chicago/Turabian Style

Bradley D Nelson; Salil Sidharthan Karipott; Robert E Guldberg; Keat Ghee Ong. 2020. "A piezoelectric bone fixation plate for in vivo application and monitoring of mechanical loading during fracture healing." Measurement Science and Technology 31, no. 9: 095703.

Original research report
Published: 23 March 2018 in Journal of Biomedical Materials Research Part B: Applied Biomaterials
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The gold standard of care for coronary artery disease, a leading cause of death for in the world, is balloon angioplasty in conjunction with stent deployment. However, implantation injuries and long‐term presence of foreign material often promotes significant luminal tissue growth, leading to a narrowing of the artery and severely restricted blood flow. A promising method to mitigate this process is the use of biodegradable metallic stents, but thus far they have either degraded too slowly (iron) or disappeared prematurely (magnesium). The present work investigates the use of a unique type of magnetic material, galfenol (iron‐gallium), for postoperative wireless control of stent degradation rates. Due to its magnetoelastic property, galfenol experiences longitudinal micron‐level elongations when exposed to applied magnetic fields, allowing generation of a microstirring effect that affect its degradation behavior. In vitro indirect cytotoxicity tests on primary rat aortic smooth muscle cells indicated that galfenol byproducts must be concentrated approximately seven times from collected 60 day degradation medium to cause ∼15% of death from all cells. Surface and cross‐sectional characterization of the material indicate that galfenol (Fe80Ga20) degradation rates (∼0.55% per month) are insufficient for stenting applications. While this material may not be ideal for comprising the entire stent, there is potential for use in combination with other materials. Furthermore, the ability to control degradation rates postimplantation opens new possibilities for biodegradable stents; additional magnetoelastic materials should be investigated for use in stenting applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2018.

ACS Style

Andrew DeRouin; Roger Guillory; Weilue He; Megan Frost; Jeremy Goldman; Keat Ghee Ong. Magnetoelastic galfenol as a stent material for wirelessly controlled degradation rates. Journal of Biomedical Materials Research Part B: Applied Biomaterials 2018, 107, 232 -241.

AMA Style

Andrew DeRouin, Roger Guillory, Weilue He, Megan Frost, Jeremy Goldman, Keat Ghee Ong. Magnetoelastic galfenol as a stent material for wirelessly controlled degradation rates. Journal of Biomedical Materials Research Part B: Applied Biomaterials. 2018; 107 (2):232-241.

Chicago/Turabian Style

Andrew DeRouin; Roger Guillory; Weilue He; Megan Frost; Jeremy Goldman; Keat Ghee Ong. 2018. "Magnetoelastic galfenol as a stent material for wirelessly controlled degradation rates." Journal of Biomedical Materials Research Part B: Applied Biomaterials 107, no. 2: 232-241.

Review
Published: 12 March 2018 in Expert Review of Medical Devices
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Introduction: Implantable wireless sensors have been used for real-time monitoring of chemicals and physical conditions of bones, tendons and muscles to diagnose and study orthopedic diseases and injuries. Due to the importance of these sensors in orthopedic care, a critical review, which not only analyzes the underlying technologies but also their clinical implementations and challenges, will provide a landscape view on their current state and their future clinical role. Areas covered: By conducting an extensive literature search and following the leaders of orthopedic implantable wireless sensors, this review covers the battery-powered and battery-free wireless implantable sensor technologies, and describes their implementation for hips, knees, spine, and shoulder stress/strain monitoring. Their advantages, limitations, and clinical challenges are also described. Expert commentary: Currently, implantable wireless sensors are mostly limited for scientific investigations and demonstrative experiments. Although rapid advancement in sensors and wireless technologies will push the reliability and practicality of these sensors for clinical realization, regulatory constraints and financial viability in medical device industry may curtail their continuous adoption for clinical orthopedic applications. In the next five years, these sensors are expected to gain increased interest from researchers, but wide clinical adoption is still unlikely.

ACS Style

Salil Sidharthan Karipott; Bradley Nelson; Robert E. Guldberg; Keat Ghee Ong. Clinical potential of implantable wireless sensors for orthopedic treatments. Expert Review of Medical Devices 2018, 15, 255 -264.

AMA Style

Salil Sidharthan Karipott, Bradley Nelson, Robert E. Guldberg, Keat Ghee Ong. Clinical potential of implantable wireless sensors for orthopedic treatments. Expert Review of Medical Devices. 2018; 15 (4):255-264.

Chicago/Turabian Style

Salil Sidharthan Karipott; Bradley Nelson; Robert E. Guldberg; Keat Ghee Ong. 2018. "Clinical potential of implantable wireless sensors for orthopedic treatments." Expert Review of Medical Devices 15, no. 4: 255-264.

Journal article
Published: 06 December 2017 in IEEE Sensors Journal
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A wireless and passive (battery-free) temperature sensor that can be embedded inside an orthopedic implant such as an interference screw was developed. The sensor is based on an inductive-capacitive-resistive (LCR) resonant circuit that is inductively powered so temperature at the implant can be measured wirelessly. A potential application of this sensor is to monitor internal wound temperature for the diagnosis of local infection at the implant site. Infections pose a significant risk to patients who receive orthopedic implants, often lead to adverse conditions including implant failure, tissue necrosis, and amputation. Current approaches for diagnosing orthopedic implant-associated infections such as blood tests, radiographic imaging and histological study are slow, tedious and nonspecific. In recent years, thermographic imaging has been used to monitor local temperature at the external surgical site as a means to detect infection, but its applications are limited to surface or near-surface wounds. The described sensor will serve as a useful research tool to investigate using temperature as an indication of deep-tissue orthopedic implant infection. When fully developed, this sensor may also improve orthopedic care by allowing simple, early detection of infection at an implant site. This paper describes the design and fabrication of the sensor, as well as characterizes its performance. Experimental results indicate the temperature response of the sensor is reproducible within the tested range of 30-42 °C.

ACS Style

Salil Sidharthan Karipott; Praharsh M. Veetil; Bradley D. Nelson; Robert E. Guldberg; Keat Ghee Ong. An Embedded Wireless Temperature Sensor for Orthopedic Implants. IEEE Sensors Journal 2017, PP, 1 -1.

AMA Style

Salil Sidharthan Karipott, Praharsh M. Veetil, Bradley D. Nelson, Robert E. Guldberg, Keat Ghee Ong. An Embedded Wireless Temperature Sensor for Orthopedic Implants. IEEE Sensors Journal. 2017; PP (99):1-1.

Chicago/Turabian Style

Salil Sidharthan Karipott; Praharsh M. Veetil; Bradley D. Nelson; Robert E. Guldberg; Keat Ghee Ong. 2017. "An Embedded Wireless Temperature Sensor for Orthopedic Implants." IEEE Sensors Journal PP, no. 99: 1-1.

Journal article
Published: 01 October 2016 in Sensor Letters
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A wireless, passive sensor was fabrication for monitoring tensile force on a wire-like structure. The sensor was made of a magnetoelastic strip attached to a rigid bracket. A tensile force applied to the metallic bracket generated a strain on the magnetoelastic strip, changing its magnetic permeability. The change in the magnetic permeability was remotely measured by applying an AC excitation magnetic field through a coil and monitoring the changes in the induced magnetic field from the strip. The advantage of this sensor is its wireless, passive nature, which makes it ideal as an embedded sensor for long term use. Furthermore, the use of solid bracket also increases the sensor's dynamic range as well as controls its force sensitivity. In this work, the performances of sensors with different designs were investigated. Specifically, sensors with various methods of connections, materials of brackets, and magnetoelastic strip placements were evaluated to determine the optimal configurations for use in different applications.

ACS Style

Yisong Tan; Andrew DeRouin; Keat Ghee Ong. Design and Optimization of a Magnetoelastic Tensile Force Sensor. Sensor Letters 2016, 14, 1049 -1053.

AMA Style

Yisong Tan, Andrew DeRouin, Keat Ghee Ong. Design and Optimization of a Magnetoelastic Tensile Force Sensor. Sensor Letters. 2016; 14 (10):1049-1053.

Chicago/Turabian Style

Yisong Tan; Andrew DeRouin; Keat Ghee Ong. 2016. "Design and Optimization of a Magnetoelastic Tensile Force Sensor." Sensor Letters 14, no. 10: 1049-1053.

Journal article
Published: 23 February 2016 in Smart Materials and Structures
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Magnetoelastic sensors are mass sensitive sensors commonly used for stress and pressure measurement, as well as chemical and biological monitoring when combined with a functionalized coating. Magnetoelastic sensors are typically made of free-standing, rectangular strips of magnetoelastic materials that exhibit longitudinal, extensional vibrations due to the excitation of magnetic fields. A single magnetoelastic sensor is generally used to monitor one parameter since only the fundamental resonant frequency is measured. Multiple-parameter sensing in close proximity has previously been achieved by using multiple magnetoelastic sensors of different dimensions and tracking their resonant frequencies independently. However, this requires a large surface area and inconvenient layout of dissimilarly shaped sensors. This paper presents a technique for monitoring multiple parameters with a single magnetoelastic sensor by applying separate mass loads at the null points (points of zero vibration) of multiple resonant modes. Applying a load at a null location does not affect the corresponding resonant mode but alters the resonant frequencies of other modes. Therefore, by isolating the variables of interest to multiple null points and simultaneously measuring the resonant frequency shifts of related resonant modes, the masses at each null location can be calculated. Results showed that changing the coverage at a null location along the width of the sensor can be used to minimize the loading effect on the corresponding resonant mode. In contrast, changing the lengthwise coverage can maximize the loading effect on other resonant modes, thus increasing the mass sensitivity of the sensor. Furthermore, simultaneously applying loads to null points of multiple resonant modes had a nearly additive effect, allowing detection of multiple parameters with a single magnetoelastic sensor.

ACS Style

Andrew DeRouin; Keat Ghee Ong. Multi-parameter sensing with a single magnetoelastic sensor by applying loads on the null locations of multiple resonant modes. Smart Materials and Structures 2016, 25, 35044 .

AMA Style

Andrew DeRouin, Keat Ghee Ong. Multi-parameter sensing with a single magnetoelastic sensor by applying loads on the null locations of multiple resonant modes. Smart Materials and Structures. 2016; 25 (3):35044.

Chicago/Turabian Style

Andrew DeRouin; Keat Ghee Ong. 2016. "Multi-parameter sensing with a single magnetoelastic sensor by applying loads on the null locations of multiple resonant modes." Smart Materials and Structures 25, no. 3: 35044.

Journal article
Published: 01 September 2015 in IEEE Transactions on Biomedical Engineering
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A new wireless sensor was designed, fabricated, and applied for in situ monitoring of tensile force at a wound site. The sensor was comprised of a thin strip of magnetoelastic material with its two ends connected to suture threads for securing the sensor across a wound repair site. Since the sensor was remotely interrogated by applying an ac magnetic field and capturing the resulting magnetic field, it did not require direct wire connections to an external device or internal battery for long-term use. Due to its magnetoelastic property, the application of a tensile force changed the magnetic permeability of the sensor, altering the amplitude of the measured magnetic field. This study presents two sensor designs: one for high and one for low-force ranges. A sensor was fabricated by directly adhering the magnetoelastic strip to the suture. This sensor showed good sensitivity at low force, but its response saturated at about 1.5 N. To monitor high tensile force, the magnetoelastic strip was attached to a metal strip for load sharing. The suture thread was attached to the both ends of the metal strip so only a fraction of the applied force was directed to the sensor, allowing it to exhibit good sensitivity even at 44.5 N. The sensor was applied to two ex vivo models: a sutured section of porcine skin and a whitetail deer Achilles tendon. The results demonstrate the potential for in vivo force monitoring at a wound repair site.

ACS Style

Andrew J. DeRouin; Nina Pacella; Chunfeng Zhao; Kai-Nan An; Keat Ghee Ong. A Wireless Sensor for Real-Time Monitoring of Tensile Force on Sutured Wound Sites. IEEE Transactions on Biomedical Engineering 2015, 63, 1665 -1671.

AMA Style

Andrew J. DeRouin, Nina Pacella, Chunfeng Zhao, Kai-Nan An, Keat Ghee Ong. A Wireless Sensor for Real-Time Monitoring of Tensile Force on Sutured Wound Sites. IEEE Transactions on Biomedical Engineering. 2015; 63 (8):1665-1671.

Chicago/Turabian Style

Andrew J. DeRouin; Nina Pacella; Chunfeng Zhao; Kai-Nan An; Keat Ghee Ong. 2015. "A Wireless Sensor for Real-Time Monitoring of Tensile Force on Sutured Wound Sites." IEEE Transactions on Biomedical Engineering 63, no. 8: 1665-1671.

Journal article
Published: 25 February 2015 in Sciencejet
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A critical property for tissue adhesives is a controllable degradation rate so that these adhesives do not act as barriers to wound healing. Typical degradation tests require large amount of samples, which can be tedious and expensive to perform. Additionally, current degradation tests are carried out in vitro under simulated physiological conditions and may not accurately reflect the complex environment that an adhesive would experience in vivo. As a means to develop a simple technique for testing tissue adhesive, a rapidly degrading adhesive hydrogel that mimics mussel adhesive proteins was coated onto magnetoelastic (ME) sensor strips to track the degradation of the adhesive remotely and in real time. Adhesive-coated ME sensors were submerged in phosphate buffer saline solution (pH 7.4) at body temperature (37 °C). Based on the change in the resonant amplitude, the degradation time was determined to be 22 min, which was in agreement with qualitative monitoring of the bulk adhesive hydrogel. Additionally, when the adhesive-coated ME sensor was incubated in a slightly acidic medium (pH 5.7), the degradation rate was drastically lengthened (3 hrs) as the hydrolysis of ester bonds is faster under basic conditions. Oscillatory rheological testing confirmed the formation and degradation of the adhesive. However, rheological test results did not accurately reflect the degradation rate of the adhesive hydrogel, potentially due to a slow exchange of acidic degradation products with the surrounding medium. ME sensor was demonstrated as a potential useful tool for evaluating the degradation rate of bioadhesives.

ACS Style

Jonathan Anderson; Meng-Hsien Lin; Caitlyn Privette; Marissa Flowers; Meridith Murley; Bruce P. Lee; Keat Ghee Ong. Wireless magnetoelastic sensors for tracking degradation profiles of nitrodopamine-modified poly(ethylene glycol). Sciencejet 2015, 4, 1 .

AMA Style

Jonathan Anderson, Meng-Hsien Lin, Caitlyn Privette, Marissa Flowers, Meridith Murley, Bruce P. Lee, Keat Ghee Ong. Wireless magnetoelastic sensors for tracking degradation profiles of nitrodopamine-modified poly(ethylene glycol). Sciencejet. 2015; 4 (80):1.

Chicago/Turabian Style

Jonathan Anderson; Meng-Hsien Lin; Caitlyn Privette; Marissa Flowers; Meridith Murley; Bruce P. Lee; Keat Ghee Ong. 2015. "Wireless magnetoelastic sensors for tracking degradation profiles of nitrodopamine-modified poly(ethylene glycol)." Sciencejet 4, no. 80: 1.

Journal article
Published: 24 February 2015 in IEEE Transactions on Biomedical Engineering
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The degradation behavior of a tissue adhesive is critical to its ability to repair a wound while minimizing prolonged inflammatory response. Traditional degradation tests can be expensive to perform, as they require large numbers of samples. The potential for using magnetoelastic resonant sensors to track bioadhesive degradation behavior was investigated. Specifically, biomimetic poly (ethylene glycol)- (PEG-) based adhesive was coated onto magnetoelastic (ME) sensor strips. Adhesive-coated samples were submerged in solutions buffered at multiple pH levels (5.7, 7.4 and 10.0) at body temperature (37 °C) and the degradation behavior of the adhesive was tracked wirelessly by monitoring the changes in the resonant amplitude of the sensors for over 80 days. Adhesive incubated at pH 7.4 degraded over 75 days, which matched previously published data for bulk degradation behavior of the adhesive while utilizing significantly less material (∼10(3) times lower). Adhesive incubated at pH 10.0 degraded within 25 days while samples incubated at pH 5.7 did not completely degrade even after 80 days of incubation. As expected, the rate of degradation increased with increasing pH as the rate of ester bond hydrolysis is higher under basic conditions. As a result of requiring a significantly lower amount of samples compared to traditional methods, the ME sensing technology is highly attractive for fully characterizing the degradation behavior of tissue adhesives in a wide range of physiological conditions.

ACS Style

Meng-Hsien Lin; Jonathan Anderson; Rattapol Pinnaratip; Hao Meng; Shari Konst; Andrew J. DeRouin; Rupak Rajachar; Keat Ghee Ong; Bruce P. Lee. Monitoring the Long-Term Degradation Behavior of Biomimetic Bioadhesive Using Wireless Magnetoelastic Sensor. IEEE Transactions on Biomedical Engineering 2015, 62, 1838 -42.

AMA Style

Meng-Hsien Lin, Jonathan Anderson, Rattapol Pinnaratip, Hao Meng, Shari Konst, Andrew J. DeRouin, Rupak Rajachar, Keat Ghee Ong, Bruce P. Lee. Monitoring the Long-Term Degradation Behavior of Biomimetic Bioadhesive Using Wireless Magnetoelastic Sensor. IEEE Transactions on Biomedical Engineering. 2015; 62 (7):1838-42.

Chicago/Turabian Style

Meng-Hsien Lin; Jonathan Anderson; Rattapol Pinnaratip; Hao Meng; Shari Konst; Andrew J. DeRouin; Rupak Rajachar; Keat Ghee Ong; Bruce P. Lee. 2015. "Monitoring the Long-Term Degradation Behavior of Biomimetic Bioadhesive Using Wireless Magnetoelastic Sensor." IEEE Transactions on Biomedical Engineering 62, no. 7: 1838-42.

Journal article
Published: 18 December 2014 in Smart Materials and Structures
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ACS Style

Nina Pacella; Andrew DeRouin; Brandon Pereles; Keat Ghee Ong. Geometrical modification of magnetoelastic sensors to enhance sensitivity. Smart Materials and Structures 2014, 24, 1 .

AMA Style

Nina Pacella, Andrew DeRouin, Brandon Pereles, Keat Ghee Ong. Geometrical modification of magnetoelastic sensors to enhance sensitivity. Smart Materials and Structures. 2014; 24 (2):1.

Chicago/Turabian Style

Nina Pacella; Andrew DeRouin; Brandon Pereles; Keat Ghee Ong. 2014. "Geometrical modification of magnetoelastic sensors to enhance sensitivity." Smart Materials and Structures 24, no. 2: 1.

Journal article
Published: 15 August 2014 in IEEE Sensors Journal
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Magnetoelastic sensors are typically made of strips of magnetostrictive materials that efficiently convert magnetic energy into mechanical energy, and vice versa. When exposed to an ac magnetic field, the sensor vibrates, producing a secondary magnetic flux that can be remotely detected. If the frequency of the ac magnetic field matches the sensor's resonant frequency, the magnetic-mechanical energy conversion is optimal, resulting in a large secondary magnetic flux. The magnetoelastic sensor has been used to monitor physical parameters relevant to force, such as mass or stress, since its resonant frequency, indirectly through the $\Delta E$ effect, is dependent on the magnitude of an applied force. Typically, the applied force must be significantly less than the weight of the sensor or it completely dampens the sensor's resonance. Presented here is the design and operation of a magnetoelastic sensor capable of monitoring large forces by applying partial loading to strategic points on a sensor. The characterization and analysis of this new magnetoelastic sensor is presented along with numerical modeling to illustrate the proposed sensing mechanism. Additionally, an array of magnetoelastic sensors were deployed to demonstrate monitoring of force loading on the lock-in portion of a lock-in style lower limb prosthetic sleeve.

ACS Style

Brandon D. Pereles; Andrew J. DeRouin; Keat Ghee Ong. Partially Loaded Magnetoelastic Sensors With Customizable Sensitivities for Large Force Measurements. IEEE Sensors Journal 2014, 15, 591 -597.

AMA Style

Brandon D. Pereles, Andrew J. DeRouin, Keat Ghee Ong. Partially Loaded Magnetoelastic Sensors With Customizable Sensitivities for Large Force Measurements. IEEE Sensors Journal. 2014; 15 (1):591-597.

Chicago/Turabian Style

Brandon D. Pereles; Andrew J. DeRouin; Keat Ghee Ong. 2014. "Partially Loaded Magnetoelastic Sensors With Customizable Sensitivities for Large Force Measurements." IEEE Sensors Journal 15, no. 1: 591-597.

Journal article
Published: 14 August 2014 in Smart Materials and Structures
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ACS Style

Hal R Holmes; Andrew DeRouin; Samantha Wright; Travor M Riedemann; Thomas A Lograsso; Rupak M Rajachar; Keat Ghee Ong. Biodegradation and biocompatibility of mechanically active magnetoelastic materials. Smart Materials and Structures 2014, 23, 95036 .

AMA Style

Hal R Holmes, Andrew DeRouin, Samantha Wright, Travor M Riedemann, Thomas A Lograsso, Rupak M Rajachar, Keat Ghee Ong. Biodegradation and biocompatibility of mechanically active magnetoelastic materials. Smart Materials and Structures. 2014; 23 (9):95036.

Chicago/Turabian Style

Hal R Holmes; Andrew DeRouin; Samantha Wright; Travor M Riedemann; Thomas A Lograsso; Rupak M Rajachar; Keat Ghee Ong. 2014. "Biodegradation and biocompatibility of mechanically active magnetoelastic materials." Smart Materials and Structures 23, no. 9: 95036.

Journal article
Published: 11 March 2014 in Journal of Functional Biomaterials
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As a prominent concern regarding implantable devices, eliminating the threat of opportunistic bacterial infection represents a significant benefit to both patient health and device function. Current treatment options focus on chemical approaches to negate bacterial adhesion, however, these methods are in some ways limited. The scope of this study was to assess the efficacy of a novel means of modulating bacterial adhesion through the application of vibrations using magnetoelastic materials. Magnetoelastic materials possess unique magnetostrictive property that can convert a magnetic field stimulus into a mechanical deformation. In vitro experiments demonstrated that vibrational loads generated by the magnetoelastic materials significantly reduced the number of adherent bacteria on samples exposed to Escherichia coli, Staphylococcus epidermidis and Staphylococcus aureus suspensions. These experiments demonstrate that vibrational loads from magnetoelastic materials can be used as a post-deployment activated means to deter bacterial adhesion and device infection.

ACS Style

Will R. Paces; Hal R. Holmes; Eli Vlaisavljevich; Katherine L. Snyder; Ee Lim Tan; Rupak M. Rajachar; Keat Ghee Ong. Application of Sub-Micrometer Vibrations to Mitigate Bacterial Adhesion. Journal of Functional Biomaterials 2014, 5, 15 -26.

AMA Style

Will R. Paces, Hal R. Holmes, Eli Vlaisavljevich, Katherine L. Snyder, Ee Lim Tan, Rupak M. Rajachar, Keat Ghee Ong. Application of Sub-Micrometer Vibrations to Mitigate Bacterial Adhesion. Journal of Functional Biomaterials. 2014; 5 (1):15-26.

Chicago/Turabian Style

Will R. Paces; Hal R. Holmes; Eli Vlaisavljevich; Katherine L. Snyder; Ee Lim Tan; Rupak M. Rajachar; Keat Ghee Ong. 2014. "Application of Sub-Micrometer Vibrations to Mitigate Bacterial Adhesion." Journal of Functional Biomaterials 5, no. 1: 15-26.

Research article
Published: 26 October 2013 in Journal of Sensors
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A wireless, passive embedded sensor was designed and fabricated for monitoring moisture in sand. The sensor, consisted of an inductive-capacitive (LC) resonant circuit, was made of a printed spiral inductor embedded inside sand. When exposed to an electromagnetic field, the sensor resonated at a specific frequency dependent on the inductance of the inductor and its parasitic capacitance. Since the permittivity of water was much higher than dry sand, moisture in sample increased the parasitic capacitance, thus decreasing the sensors resonant frequency. Therefore, the internal moisture level of the sample could be easily measured through tracking the resonant frequency using a detection coil. The fabrication process of this sensor is much simpler compared to LC sensors that contain both capacitive and inductive elements, giving it an economical advantage. A study was conducted to investigate the drying rate of sand samples of different grain sizes. The experimental data showed a strong correlation with the actual moisture content in the samples. The described sensor technology can be applied for long term monitoring of localized water content inside soils and sands to understand the environmental health in these media, or monitoring moisture levels within concrete supports and road pavement.

ACS Style

Andrew J. DeRouin; Zhanping You; Morgan Hansen; Aboelkasim Diab; Keat Ghee Ong. Development and Application of the Single-Spiral Inductive-Capacitive Resonant Circuit Sensor for Wireless, Real-Time Characterization of Moisture in Sand. Journal of Sensors 2013, 2013, 1 -7.

AMA Style

Andrew J. DeRouin, Zhanping You, Morgan Hansen, Aboelkasim Diab, Keat Ghee Ong. Development and Application of the Single-Spiral Inductive-Capacitive Resonant Circuit Sensor for Wireless, Real-Time Characterization of Moisture in Sand. Journal of Sensors. 2013; 2013 (1):1-7.

Chicago/Turabian Style

Andrew J. DeRouin; Zhanping You; Morgan Hansen; Aboelkasim Diab; Keat Ghee Ong. 2013. "Development and Application of the Single-Spiral Inductive-Capacitive Resonant Circuit Sensor for Wireless, Real-Time Characterization of Moisture in Sand." Journal of Sensors 2013, no. 1: 1-7.

Journal article
Published: 01 September 2013 in Sensor Letters
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ACS Style

Andrew J. DeRouin; Steven J. Trierweiler; Brandon D. Pereles; Benjamin Lippi; Keat Ghee Ong. A Low Cost, Wireless Embedded Sensor for Moisture Monitoring in Hard-to-Access Places. Sensor Letters 2013, 11, 1573 -1578.

AMA Style

Andrew J. DeRouin, Steven J. Trierweiler, Brandon D. Pereles, Benjamin Lippi, Keat Ghee Ong. A Low Cost, Wireless Embedded Sensor for Moisture Monitoring in Hard-to-Access Places. Sensor Letters. 2013; 11 (9):1573-1578.

Chicago/Turabian Style

Andrew J. DeRouin; Steven J. Trierweiler; Brandon D. Pereles; Benjamin Lippi; Keat Ghee Ong. 2013. "A Low Cost, Wireless Embedded Sensor for Moisture Monitoring in Hard-to-Access Places." Sensor Letters 11, no. 9: 1573-1578.

Journal article
Published: 01 January 2013 in Journal of Sensor Technology
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A wireless passive sensor array based on inductive-capacitive (LC) resonant circuits capable of simultaneously tracking two points of force loading is described. The sensor consisted of a planar spiral inductor connected to two capacitors forming a resonant circuit with two resonant frequencies. When a load was applied to one or both of the parallel plate capacitors, the distance between the plates of the capacitor was altered, thus shifting the observed resonant peaks. Testing illustrated that applied loading to a particular capacitor caused a significant shift in one of the resonant peaks and also a smaller shift in another resonant peak. This interdependence resulted from each capacitive element being connected to the same inductive spiral and was accounted for with a developed analysis algorithm. To validate the experimental observation, a circuit simulation was also generated to model the sensor behavior with changing force/displacement. The novelty of this system lies not only in its wireless passive nature, but also in the fact that a single LC sensor was fashioned to detect more than one point simultaneously.

ACS Style

Andrew J. DeRouin; Brandon D. Pereles; Thadeus M. Sansom; Peng Zang; Keat Ghee Ong. A Wireless Inductive-Capacitive Resonant Circuit Sensor Array for Force Monitoring. Journal of Sensor Technology 2013, 03, 63 -69.

AMA Style

Andrew J. DeRouin, Brandon D. Pereles, Thadeus M. Sansom, Peng Zang, Keat Ghee Ong. A Wireless Inductive-Capacitive Resonant Circuit Sensor Array for Force Monitoring. Journal of Sensor Technology. 2013; 03 (03):63-69.

Chicago/Turabian Style

Andrew J. DeRouin; Brandon D. Pereles; Thadeus M. Sansom; Peng Zang; Keat Ghee Ong. 2013. "A Wireless Inductive-Capacitive Resonant Circuit Sensor Array for Force Monitoring." Journal of Sensor Technology 03, no. 03: 63-69.