Reliability Assurance and Testing

Licari, James J.

doi:10.1016/b978-081551492-3.50007-6

Cited by 30 publications

(39 citation statements)

References 18 publications

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“…[33] The low thermal conductivity of silicone polymer (i.e., 0.2 W m −1 K −1 ) [34,35] made it a suitable thermal insulation layer for the SMA wires to reduce the heat transfer to the balloon, and later to the bladder. Therefore, medical grade silicone tubing (Silcon) with inner diameters of 500 µm and outer diameters of 965 µm was used as the thermal insulation layer for the SMA wire.…”

Section: Actuating Device Design and Fabricationmentioning

confidence: 99%

Design and Anchorage Dependence of Shape Memory Alloy Actuators on Enhanced Voiding of a Bladder

Hassani

Gammad

Mogan

et al. 2017

Adv Materials Technologies

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for such transformation. [3] Voluntary repeatable shape transformation, material biocompatibility, and small weight of NiTi shape memory alloy (SMA) actuators make them suitable for medical applications. [4][5][6][7][8][9][10][11][12] Usage of NiTi SMA actuators for muscular contraction, [8] artificial anal sphincter, [7] urethral valve, [13] myocardium, [8] drug delivery system, [3] and most recently, voiding of a bladder, [14] has been reported.The previous SMA-based actuator for voiding of a bladder consisted of a flexible vest that covered the bladder surface and physically contracted it upon the actuation of assembled SMA wires. [14] Since a fixed length was considered for SMA wires in this design, the device could be used for only one bladder size that was matched with the total inner diameter of actuator. The proposed design in our study has a more conformable vest that can be fitted for a wider range of bladder sizes in rats with similar body weight, and can substantially improve the voiding volume and energy consumption of the device.The previous SMA-based actuator was proposed for assisting the detrusor muscle in myogenic underactive bladder (UAB) patient with detrusor muscle contractility disorder but intact nerves. [14] Our study broadens the application of the actuating device also to neurogenic UAB patients suffering from both damaged detrusor muscle and nervous system; these patients are not able to rely on the natural nerve pathways to realize The use of shape memory alloy (SMA) actuators to restore voiding of bladder for myogenic under active bladder (UAB) patients is proposed recently. Even though previous work show the unique capability of this technology for bladder voiding, the low voiding volume and high energy consumption of the device limit the advancement of this technique. This study proposes a novel approach using an interlaced configuration to overcome these limitations. In this device, SMA actuators are threaded through rigid anchor points of the flexible vest. The novel anchorage of SMA actuators provides more conformability for the vest and lower energy consumption for the device, while the new interlaced configuration enhances the voiding volume. The device is tested initially on a rubber model for the bladder, then it is implanted in an anesthetized rat, and a voiding volume of more than 20% at 4 V is successfully achieved. A commercial force sensor is integrated with the device to make it suitable for neurogenic UAB patients. The sensor provides a feedback control signal to the patient to initiate the actuation of the device upon fullness of bladder. The overall system is a promising advance over the state-of-the-art providing bladder voiding in UAB patients.

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Section: Actuating Device Design and Fabricationmentioning

confidence: 99%

Design and Anchorage Dependence of Shape Memory Alloy Actuators on Enhanced Voiding of a Bladder

Hassani

Gammad

Mogan

et al. 2017

Adv Materials Technologies

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“…Parylene-C provides the requisite controlled deposition of a sealing material into the small spaces between the capillary and the microfluidic channel. It is an attractive material for biomedical fluidic interconnects due to its biocompatibility and chemical resistance [10]. Parylene has been used for conformal coating [11], pore-filling [12], microchannel formation [13], and channel penetration [14], [15].…”

Section: Introductionmentioning

confidence: 99%

In-Plane Biocompatible Microfluidic Interconnects for Implantable Microsystems

Johnson

Frisina

Borkholder

2011

IEEE Trans. Biomed. Eng.

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Small mammals, particularly mice, are very useful animal models for biomedical research. Extremely small anatomical dimensions, however, make design of implantable microsystems quite challenging. A method for coupling external fluidic systems to microfluidic channels via in-plane interconnects is presented. Capillary tubing is inserted into channels etched in the surface of a Si wafer with a seal created by Parylene-C deposition. Prediction of Parylene-C deposition into tapered channels based on Knudsen diffusion and deposition characterizations allows for design optimization. Low-volume interconnects using biocompatible, chemical resistant materials have been demonstrated and shown to withstand pressure as high as 827 kPa (120 psi) with an average pull test strength of 2.9 N. Each interconnect consumes less than 0.018 mm3 (18 nL) of volume. The low added volume makes this an ideal interconnect technology for medical applications where implant volume is critical.

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“…Parylene-C (chlorinated poly-para-xylylene) is an attractive material for fluidic systems due to its biocompatibility and chemical resistance [2]. Polyimide tubing, USP Class VI compliant, has been used for biomedical implants as medical probes [3], and micro-channels [4] and is well suited for use as cannulae [5].…”

Section: Introductionmentioning

confidence: 99%

Implantable micropump technologies for murine intracochlear infusions

Johnson

Waldron

Frisina

et al. 2010

2010 Annual International Conference of the IEEE Engineering in Medicine and Biology

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Due to the very small size of the mouse inner ear, 600 nL volume, developing effective, controlled infusion systems is quite challenging. Key technologies have been created to minimize both size and power for an implantable pump for murine intracochlear infusions. A method for coupling fine capillary tubing to microfluidic channels is presented which provides low volume, biocompatible interconnects withstanding pressures as high as 827 kPa (120 psi) and consuming less than 20 nL of volume exiting in-plane with the pump. Surface micromachined resistive bridges integrated into the flow channel for anemometry based flow rate measurement have been optimized for low power operation in the ultra-low flow rate regime. A process for creation of deformable diaphragms over pump chambers with simultaneous coating of the microfluidic channels has been developed allowing integration of a biocompatible fluid flow path. These advances represent enabling capabilities for a drug delivery system suitable for space constrained applications such as subcutaneous implantation in mice.

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Reliability Assurance and Testing

Cited by 30 publications

References 18 publications

Design and Anchorage Dependence of Shape Memory Alloy Actuators on Enhanced Voiding of a Bladder

Design and Anchorage Dependence of Shape Memory Alloy Actuators on Enhanced Voiding of a Bladder

In-Plane Biocompatible Microfluidic Interconnects for Implantable Microsystems

Implantable micropump technologies for murine intracochlear infusions

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