A stepping micromotor based on ferrofluid bearing for side-viewing microendoscope applications

Jayhooni, Sayed Mohammad Hashem; Assadsangabi, Babak; Takahata, Kenichi

doi:10.1016/j.sna.2017.11.020

Cited by 22 publications

(9 citation statements)

References 28 publications

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“…[7][8][9][10][11] The micro/nanomotors are nanoscale materials which convert chemical energy into force and movement. [12] Generally, they have been used in approaches which focused on biomedical sciences, [8,[13][14][15] but micro/nanomotors exhibited unique potentials for environmental remediation and water purification. [16][17][18][19] The combination of active motion and surface multifunctionalities introduced a new artificial swimmers for use in water purification such as degradation of organic magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Self‐Propelled Micro/Nanomotors for Sensing and Environmental Remediation

Zarei

2018

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140

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Self-propelled micro/nanomotors have gained attention for successful application in cargo delivery, therapeutic treatments, sensing, and environmental remediation. Unique characteristics such as high speed, motion control, selectivity, and functionability promote the application of micro/nanomotors in analytical sciences. Here, the recent advancements and main challenges regarding the application of self-propelled micro/nanomotors in sensing and environmental remediation are discussed. The current state of micro/nanomotors is reviewed, emphasizing the period of the last five years, then their developments into the future applications for enhanced sensing and efficient purification of water resources are extrapolated.

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Section: Introductionmentioning

confidence: 99%

Self‐Propelled Micro/Nanomotors for Sensing and Environmental Remediation

Zarei

2018

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140

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“…The stator coils are designed to set four physical poles of electromagnetic fields around the tubular surface with a 90° offset from adjacent poles. Arbitrary angular positioning of the rotor is achieved through the pulse‐width‐modulation (PWM) method that controls the amount and direction of the currents distributed to the two stator coils using a current divider/controller . An exact angular position is set by the balance between the intensities of the fields determined by the amounts of currents that flow through two adjacent coil lines (Figure S2, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

“…This work is particularly intended for the application of detecting peripheral lung cancers grown on the sidewalls of narrow bronchi ( Figure a). This functionality is enabled with a ferrofluid‐assisted MEMS rotary stepping actuator that we custom‐developed for medical catheter applications . This micro actuator is designed to rotate and scan a probing laser beam for 360° circumferential coverage, with a pre‐determined stepping angle that can be programmed.…”

Section: Introductionmentioning

confidence: 99%

Side‐Viewing Endoscopic Raman Spectroscopy for Angle‐Resolved Analysis of Luminal Organs

Jayhooni

Short²,

Assadsangabi

et al. 2019

Adv Materials Technologies

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There are many medical applications requiring angle‐resolved analysis of luminal organs. One example is lung cancer detection. Early diagnosis is the most effective way to tackle this disease. This, however, remains a challenge due to the lack of accurate detection technology. The problem is exacerbated in cases of peripheral lung cancer growing on narrow bronchi that are difficult to probe. Here, an endoscopic Raman spectroscopy device is demonstrated with a side‐viewing functionality that enables circumferential scanning spectral measurements inside thin conduits. A tubular micro rotary stepping actuator is custom‐designed and integrated with a Raman probe, for the first time, to scan a probing laser beam sideways for angle‐resolved local Raman analysis with no aid of tissue labeling, toward enabling detection of lesion‐induced biochemical changes in vivo and in real time. A microfabricated prototype is evaluated using test chemicals, harvested animal lung tissue ex vivo, as well as a murine colon model in situ and human skin in vivo. All the test results show excellent agreements with reported reference data while revealing >99% wavenumber accuracies. The study indicates that microactuator‐assisted endoscopic Raman spectroscopy is a promising technology for luminal tissue analysis and encourages further studies of its sensitivity in lesion detection.

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“…The principle of force generation in these situations is that any displacement causing a localized increase in magnetic flux density will result in a corresponding increase in fluid pressure in that region, thereby producing a restoring force that will tend to stabilize the supported object’s position. The same principle can be exploited in the creation of fluid-film bearings that combine electrical or permanent magnets with ferrofluid 1 , 20 – 23 . For some newly proposed ferrofluid actuation systems, permanent magnets have been used to generate magnetic fields that are then varied in strength differentially using electrical coils 6 , 16 .…”

Section: Introductionmentioning

confidence: 97%

On force generation in electro-fluidic linear actuators with ferrofluid

Cole

Moran

2022

Sci Rep

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In ferrofluid actuation systems, forces are generated by actively controlling pressure and flow within the fluid using an applied magnetic field. There are multiple contributing factors in force generation involving complex non-linear couplings between electromagnetic and fluid pressure fields. This brings significant challenges in theory-based design and optimization. In this paper, a theoretical model of pressure transmission between a ferrofluid and solid is derived starting from Maxwell’s stress tensor and accounting for magnetic saturation within the fluid. This model shows that linear actuator designs based on orthogonal mode operation, where the field direction through the fluid is perpendicular to the motion direction, can provide the highest force capacity for a given field strength from the actuator coil. This is verified by theoretical analysis of some basic linear actuator topologies. The results are applied in the design and analysis of a novel piston-type linear actuator with sealed chamber and two internal electrical coils for bidirectional operation. Experimental measurements of both static and dynamic behaviour are shown to validate the described principles. The actuator produces smooth and precise flow-regulated motion, has zero intrinsic stiffness, and exhibits very low friction due to the suspension effect from ferrofluid layers within the actuator.

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A stepping micromotor based on ferrofluid bearing for side-viewing microendoscope applications

Cited by 22 publications

References 28 publications

Self‐Propelled Micro/Nanomotors for Sensing and Environmental Remediation

Self‐Propelled Micro/Nanomotors for Sensing and Environmental Remediation

Side‐Viewing Endoscopic Raman Spectroscopy for Angle‐Resolved Analysis of Luminal Organs

On force generation in electro-fluidic linear actuators with ferrofluid

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