Design and Evaluation of a Steerable Magnetic Sheath for Cardiac Ablations

Chautems, Christophe; Lyttle, Sean; Boehler, Quentin; Nelson, Bradley J.

doi:10.1109/lra.2018.2809546

Cited by 42 publications

(23 citation statements)

References 19 publications

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“…As the water temperature rose, the device with the full hydrogel dimensions gradually uncurled to straighten the tip, reaching a bending angle of 170° when temperature was raised to 50 °C. This bending amount is found to be the largest among other reported smart-material-based catheters (13-155°) [13][14][15][16]. As also can be seen, the devices with the halved length or thickness of the hydrogel layer showed actuations with reduced bending angles as expected.…”

Section: Characterization Of Pnipam Synthesized On the Flexible Stripsupporting

confidence: 74%

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Electrothermally Driven Hydrogel-on-Flex-Circuit Actuator for Smart Steerable Catheters

Selvaraj

Takahata

2020

Micromachines

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This paper reports an active catheter-tip device functionalized by integrating a temperature-responsive smart polymer onto a microfabricated flexible heater strip, targeting at enabling the controlled steering of catheters through complex vascular networks. A bimorph-like strip structure is enabled by photo-polymerizing a layer of poly(N-isopropylacrylamide) hydrogel (PNIPAM), on top of a 20 × 3.5 mm2 flexible polyimide film that embeds a micropatterned heater fabricated using a low-cost flex-circuit manufacturing process. The heater activation stimulates the PNIPAM layer to shrink and bend the tip structure. The bending angle is shown to be adjustable with the amount of power fed to the device, proving the device’s feasibility to provide the integrated catheter with a controlled steering ability for a wide range of navigation angles. The powered device exhibits uniform heat distribution across the entire PNIPAM layer, with a temperature variation of <2 °C. The operation of fabricated prototypes assembled on commercial catheter tubes demonstrates their bending angles of up to 200°, significantly larger than those reported with other smart-material-based steerable catheters. The temporal responses and bending forces of their actuations are also characterized to reveal consistent and reproducible behaviors. This proof-of-concept study verifies the promising features of the prototyped approach to the targeted application area.

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Section: Characterization Of Pnipam Synthesized On the Flexible Stripsupporting

confidence: 74%

“…Different approaches to this goal have been reported [13][14][15][16]. One promising approach that has been widely investigated is to use responsive "smart" materials as the actuator element aiming to achieve greater bending controllability, simpler system configurations, and miniaturization of the active tip [17].…”

Section: Introductionmentioning

confidence: 99%

Electrothermally Driven Hydrogel-on-Flex-Circuit Actuator for Smart Steerable Catheters

Selvaraj

Takahata

2020

Micromachines

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“…Next, the magnetic steering demonstrated in the paper was achieved manually by adjusting the position and orientation of a single permanent magnet. To improve the accuracy and precision, existing magnetic manipulation systems (15,(47)(48)(49)(50) or more recent developments in omnidirectional and/or spatially selective magnetic field control (17,18,21,(51)(52)(53) will need to be adopted for further translation of the proposed concept of ferromagnetic soft continuum robots.…”

Section: Discussionmentioning

confidence: 99%

Ferromagnetic soft continuum robots

et al. 2019

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Small-scale soft continuum robots capable of active steering and navigation in a remotely controllable manner hold great promise in diverse areas, particularly in medical applications. Existing continuum robots, however, are often limited to millimeter or centimeter scales due to miniaturization challenges inherent in conventional actuation mechanisms, such as pulling mechanical wires, inflating pneumatic or hydraulic chambers, or embedding rigid magnets for manipulation. In addition, the friction experienced by the continuum robots during navigation poses another challenge for their applications. Here, we present a submillimeter-scale, self-lubricating soft continuum robot with omnidirectional steering and navigating capabilities based on magnetic actuation, which are enabled by programming ferromagnetic domains in its soft body while growing hydrogel skin on its surface. The robot’s body, composed of a homogeneous continuum of a soft polymer matrix with uniformly dispersed ferromagnetic microparticles, can be miniaturized below a few hundreds of micrometers in diameter, and the hydrogel skin reduces the friction by more than 10 times. We demonstrate the capability of navigating through complex and constrained environments, such as a tortuous cerebrovascular phantom with multiple aneurysms. We further demonstrate additional functionalities, such as steerable laser delivery through a functional core incorporated in the robot’s body. Given their compact, self-contained actuation and intuitive manipulation, our ferromagnetic soft continuum robots may open avenues to minimally invasive robotic surgery for previously inaccessible lesions, thereby addressing challenges and unmet needs in healthcare.

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“…S7). While guidewires/catheters with different single magnets have been fabricated (18)(19)(20)(21)(22)(23), their half workspaces are always a curve with an area of 0 (Fig. 5 and SI Appendix, section 3).…”

Section: [3]mentioning

confidence: 99%

“…Existing MSCRs are mostly fabricated by embedding one or more permanent magnets in the distal portion of the MSCR (18)(19)(20)(21)(22)(23)(24)(25). More recently, a new type of MSCR has been developed by uniformly dispersing hard-magnetic particles in elastomeric fibers (16) (Fig.…”

mentioning

confidence: 99%

Evolutionary design of magnetic soft continuum robots

Wang

Zheng

Harker

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

122

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Worldwide cardiovascular diseases such as stroke and heart disease are the leading cause of mortality. While guidewire/catheter-based minimally invasive surgery is used to treat a variety of cardiovascular disorders, existing passive guidewires and catheters suffer from several limitations such as low steerability and vessel access through complex geometry of vasculatures and imaging-related accumulation of radiation to both patients and operating surgeons. To address these limitations, magnetic soft continuum robots (MSCRs) in the form of magnetic field–controllable elastomeric fibers have recently demonstrated enhanced steerability under remotely applied magnetic fields. While the steerability of an MSCR largely relies on its workspace—the set of attainable points by its end effector—existing MSCRs based on embedding permanent magnets or uniformly dispersing magnetic particles in polymer matrices still cannot give optimal workspaces. The design and optimization of MSCRs have been challenging because of the lack of efficient tools. Here, we report a systematic set of model-based evolutionary design, fabrication, and experimental validation of an MSCR with a counterintuitive nonuniform distribution of magnetic particles to achieve an unprecedented workspace. The proposed MSCR design is enabled by integrating a theoretical model and the genetic algorithm. The current work not only achieves the optimal workspace for MSCRs but also provides a powerful tool for the efficient design and optimization of future magnetic soft robots and actuators.

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Design and Evaluation of a Steerable Magnetic Sheath for Cardiac Ablations

Cited by 42 publications

References 19 publications

Electrothermally Driven Hydrogel-on-Flex-Circuit Actuator for Smart Steerable Catheters

Electrothermally Driven Hydrogel-on-Flex-Circuit Actuator for Smart Steerable Catheters

Ferromagnetic soft continuum robots

Evolutionary design of magnetic soft continuum robots

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