In situ and ex vivo evaluation of a wireless magnetoelastic biliary stent monitoring system

Green, Scott Ryan; Kwon, Richard S.; Elta, Grace H.; Gianchandani, Yogesh B.

doi:10.1007/s10544-010-9404-7

Cited by 15 publications

(16 citation statements)

References 10 publications

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“…[1][2][3][4][5] Similarly, freestanding beams made of ferromagnetic material as a sensor platform have been widely studied for detection of physical, chemical, and biochemical substances. [6][7][8][9][10][11][12][13] These beams operate in the longitudinal mode offering a higher resonant frequencies compared to the transverse mode. Figs.…”

Section: Introductionmentioning

confidence: 99%

Development of FeNiMoB thin film materials for microfabricated magnetoelastic sensors

Cai

Gooneratne

Cha

et al. 2012

Journal of Applied Physics

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MetglasTM 2826MB foils of 25–30 μm thickness with the composition of Fe40Ni38Mo4B18 have been used for magnetoelastic sensors in various applications over many years. This work is directed at the investigation of ∼3 μm thick iron-nickel-molybdenum-boron (FeNiMoB) thin films that are intended for integrated microsystems. The films are deposited on Si substrate by co-sputtering of iron-nickel (FeNi), molybdenum (Mo), and boron (B) targets. The results show that dopants of Mo and B can significantly change the microstructure and magnetic properties of FeNi materials. When FeNi is doped with only Mo its crystal structure changes from polycrystalline to amorphous with the increase of dopant concentration; the transition point is found at about 10 at. % of Mo content. A significant change in anisotropic magnetic properties of FeNi is also observed as the Mo dopant level increases. The coercivity of FeNi films doped with Mo decreases to a value less than one third of the value without dopant. Doping the FeNi with B together with Mo considerably decreases the value of coercivity and the out-of-plane magnetic anisotropy properties, and it also greatly changes the microstructure of the material. In addition, doping B to FeNiMo remarkably reduces the remanence of the material. The film material that is fabricated using an optimized process is magnetically as soft as amorphous MetglasTM 2826MB with a coercivity of less than 40 Am−1. The findings of this study provide us a better understanding of the effects of the compositions and microstructure of FeNiMoB thin film materials on their magnetic properties.

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Section: Introductionmentioning

confidence: 99%

Development of FeNiMoB thin film materials for microfabricated magnetoelastic sensors

Cai

Gooneratne

Cha

et al. 2012

Journal of Applied Physics

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“…Similarly, the number of turns in the transmit coils have been reduced in order to lower the coil impedance and increase the magnitude of the transmitted magnetic field at the frequencies of interest. Overall, these changes increase the SNR by a factor of 7 compared to our previous work [Gre10A]. …”

Section: Designmentioning

confidence: 56%

“…For in situ testing of the sensor array, a procedure similar to that used and discussed in [Gre10A] was used. After euthanization of a female domestic swine of approximately 42 kg mass, a laparotomy was performed.…”

Section: 0 Experimental Methods and Resultsmentioning

confidence: 99%

“…We have previously reported on the basic architecture and bench-top performance of this system, as well as the performance of a single sensor in a self-expanding metal stent in in situ tests on a porcine carcass in a surgical setting [Gre09, Gre10A, Gre10B]. However, a number of key challenges remain regarding the feasibility of this technology in a practical clinical setting and utilizing an array of sensors.…”

Section: Introductionmentioning

confidence: 99%

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In vivo and in situ evaluation of a wireless magnetoelastic sensor array for plastic biliary stent monitoring

Green¹,

Kwon

Elta

et al. 2013

Biomed Microdevices

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This paper presents the in vivo and in situ evaluation of a system that wirelessly monitors the accumulation of biliary sludge in a plastic biliary stent. The sensing element, located within the stent, is a passive array of magnetoelastic resonators that is queried by a wireless electromagnetic signal. The in vivo and in situ testing uses commercially-available plastic biliary stents, each enhanced with an array of ribbon sensors (formed from Metglas™ 2826MB). The sensor array is approximately 70 mm long and contains individual resonators that are 1 mm in width and have lengths of 10 mm, 14 mm, and 20 mm. The array is anchored into the 2.8 mm inner-diameter stent using a thermal staking technique. For the in situ testing, an instrumented stent is placed in various locations within the abdominal cavity of a female domestic swine carcass to evaluate the wireless range of the system; these results show that a wireless signal can be obtained from a range of at least 7.5 cm from a sensor array covered in bile. The in vivo testing includes the endoscopic implantation of an instrumented stent into the bile duct of a swine. After implantation, the swine was housed for a period of 4 weeks, during which the animal showed no ill effects and followed the expected growth curve from 29 kg to 42 kg. At the conclusion of the in vivo test, the animal was euthanized, and the instrumented stent explanted and examined. The results presented in this paper indicate that the monitoring system does not adversely affect the health of the animal and can feasibly provide sufficient wireless range after implantation.

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“…Our previous work demonstrated magnetoelastic sensors incorporated with stents for sludge accumulation in a biliary stent [6][7][8]. Initial designs were tethered to the stents with anchors, separating sensor and the stent [6].…”

Section: Introductionmentioning

confidence: 99%

Metglas–Elgiloy bi-layer, stent cell resonators for wireless monitoring of viscosity and mass loading

Viswanath

Green

Kosel

et al. 2012

J. Micromech. Microeng.

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This paper presents the design and evaluation of magnetoelastic sensors intended for wireless monitoring of tissue accumulation in peripheral artery stents. The sensors are fabricated from 28 μm thick foils of magnetoelastic 2826MB Metglas TM , an amorphous Ni-Fe alloy. The sensor layer consists of a frame and an active resonator portion. The frame consists of 150 μm wide struts that are patterned in the same wishbone array pattern as a 12 mm × 1.46 mm Elgiloy stent cell. The active portion is a 10 mm long symmetric leaf shape and is anchored to the frame at mid length. The active portion nests within the stent cell, with a uniform gap separating the two. A gold-indium eutectic bonding process is used to bond Metglas TM and Elgiloy foils, which are subsequently patterned to form bi-layer resonators. The response of the sensor to viscosity changes and mass loading that precede and accompany artery occlusion is tested in vitro. The typical sensitivity to viscosity of the fundamental, longitudinal resonant frequency at 361 kHz is 427 ppm cP −1 over a 1.1-8.6 cP range. The sensitivity to mass loading is typically between 63000 and 65000 ppm mg −1 with the resonant frequency showing a reduction of 8.1% for an applied mass that is 15% of the unloaded mass of the sensor. This is in good agreement with the theoretical response.

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In situ and ex vivo evaluation of a wireless magnetoelastic biliary stent monitoring system

Cited by 15 publications

References 10 publications

Development of FeNiMoB thin film materials for microfabricated magnetoelastic sensors

Development of FeNiMoB thin film materials for microfabricated magnetoelastic sensors

In vivo and in situ evaluation of a wireless magnetoelastic sensor array for plastic biliary stent monitoring

Metglas–Elgiloy bi-layer, stent cell resonators for wireless monitoring of viscosity and mass loading

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