Swimming Micro Robots for Medical Applications

Kósa, Gábor; Székely, Gábor

doi:10.1007/978-1-4419-1126-1_16

Cited by 4 publications

(3 citation statements)

References 76 publications

(72 reference statements)

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“…We showed earlier (Kosa et al 2008a, b, Kosa and Szekely 2010) that combining three piezoelectric swimming tails will provide sufficient propulsion to swim in the body. The propulsive force of a magnetic tail is one order of magnitude higher than a piezoelectric one thus this device will be able swim effectively.…”

Section: Discussionmentioning

confidence: 71%

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MRI driven magnetic microswimmers

Kósa

Jakab

Székely

et al. 2011

Biomed Microdevices

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Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW power and the tail located within the homogeneous field of a 3 T MRI scanner. We also analyze the parallel operation of the swimming mechanism and the scanner imaging. We characterize the size of artifacts caused by the propulsion system. We show that while the magnetic micro swimmer is propelling the capsule endoscope, the operator can locate the capsule on the image of an interventional scene without being obscured by significant artifacts. Although this swimming method does not scale down favorably, the high magnetic field of the MRI allows self propulsion speed on the order of several millimeter per second and can propel an endoscopic capsule in the stomach.

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Section: Discussionmentioning

confidence: 71%

“…Earlier we published a theoretical analysis of the swimming method presented in this paper Kosa et al 2008b and initial experimental results (Kosa et al 2008b, Kosa 2010). In those earlier papers we used a tail having 3 coils and a model of traveling wave in an elastic beam in a low Reynolds number fluidic environment.…”

Section: Introductionmentioning

confidence: 92%

MRI driven magnetic microswimmers

Kósa

Jakab

Székely

et al. 2011

Biomed Microdevices

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“…In engineering domain, due to advancements in microfabrication technology, micron sized robots (microswimmers) with the capability to perform high end task are now feasible [2,3]. At present, these tasks are oriented mainly towards biomedical applications such as minimal invasive targeted drug delivery, micromanipulation, and therapeutic diagnosis [4][5][6]. The motion of a biological microswimmer has its own specific mechanism due to operation at low Reynolds number (Re) condition where the viscous forces dominate over the inertial forces [7].…”

Section: Introductionmentioning

confidence: 99%

Navigation control of flagellated magnetic microswimmer by parametric excitation

Singh¹,

Yadava²

2019

J. Phys. D: Appl. Phys.

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The paper presents a novel mechanism for controlling swimming behavior of a flagellated microswimmer by parametric excitation. The microswimmer design consists of a spherical rigid magnetic head attached to a slender rigid link (tail) via torsional spring joint. The swimmer is actuated by an oscillating magnetic field that produces undulatory coplanar motion. The parametric excitation consists of harmonic modulation of elastic stiffness of the spring joint. The equation of motion is described by the balance of forces and torques at low Reynolds number. The analytical solutions were obtained by harmonic balance method under small amplitude approximation. It is found that the parametric excitation modifies the symmetry and amplitude of beating patterns of the tail. The influence of these on microswimmer performance (time-averaged displacement and propulsion velocity along longitudinal and transverse directions) is analyzed. A comparison with the performance of a microswimmer without parametric excitation shows that the propulsion velocity can be enhanced or suppressed by tuning the phase difference between parametric excitation and magnetic actuation. Also, not only the longitudinal propulsion but a simultaneous transverse propulsion is generated by the parametric excitation. This facilitates the navigational control of the microswimmer by parametric modulation.

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Small‐Scale Robots in Fluidic Media

Kósa

Hunziker

2019

Advanced Intelligent Systems

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One of the most promising uses of miniature robots (MRs) in the biomedical field is performing local in situ diagnosis and therapy. Researchers have proposed numerous swimming methods utilizing various actuation principles. Herein, the different propulsion methods of MRs are evaluated by analyzing their scalability. Comparing various actuators, how their performance changes with size reduction is evaluated. The swimming of natural flagellar swimmers such as spermatozoa and nematodes is analyzed. It is found that although the fluidic regime and the geometry of these organisms change considerably, there are nondimensional features that remain almost constant; most importantly, the variation of the swimming velocity is much smaller than the variation of the Reynolds number in natural swimmers. Then, several methods of propulsion and actuation principles are compared, and it is found that among the swimming methods examined, the downscaling of a piezoelectrically driven vibrating elastic beam is the most favorable. Similar to natural swimmers, the swimming velocity of a piezoelectric active swimming tail does not depend on the geometry given that its power requirements can be met. This comparative approach tool aids in the development of future actuation methods for MRs and other active microsystems.

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Swimming Micro Robots for Medical Applications

Cited by 4 publications

References 76 publications

MRI driven magnetic microswimmers

MRI driven magnetic microswimmers

Navigation control of flagellated magnetic microswimmer by parametric excitation

Small‐Scale Robots in Fluidic Media

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