Untethered magnetic millirobot for targeted drug delivery

Iacovacci, Veronica; Lucarini, Gioia; Ricotti, Leonardo; Dario, P.; Dupont, Pierre E.; Menciassi, Arianna

doi:10.1007/s10544-015-9962-9

Cited by 31 publications

(27 citation statements)

References 41 publications

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Section: Introductionmentioning

confidence: 99%

“…These challenges mean that most artificial microrobots actually have no actuators. Rather, they are in most cases rigid monolithic structures, either pushed by chemical reactions 15 or directly 4 manipulated by torques or forces applied by external magnetic fields [16][17][18][19][20] .Alternatively, they consist of flexible materials embedding, at best, a small number of passive degrees of freedom (DOFs) 21,22 .In macroscale robots, one approach to increase the number of DOFs has been to adopt soft bodies, capable of biomimetic actuation [23][24][25][26][27][28] . However, these approaches have resisted miniaturization.…”

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confidence: 99%

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Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots

et al. 2016

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Microorganisms move in challenging environments by periodic changes in body shape. By contrast, current artificial microrobots cannot actively deform, exhibiting at best passive bending under external fields. Here, by taking advantage of the wireless, scalable and spatiotemporally selective capabilities that light allows, we show that soft microrobots consisting of photoactive liquid-crystal elastomers can be driven by structured monochromatic light to perform sophisticated biomimetic motions. We realized continuum yet selectively addressable artificial microswimmers that generate travelling-wave motions to self-propel without external forces or torques, as well as microrobots capable of versatile locomotion behaviours on demand. Both theoretical predictions and experimental results confirm that multiple gaits, mimicking either symplectic or antiplectic metachrony of ciliate protozoa, can be achieved with single microrobots. The principle of using structured light can be extended to other applications that require microscale actuation with sophisticated spatiotemporal coordination for advanced microrobotic technologies. 3Mobile micro-scale robots are envisioned to navigate within the human body to perform minimally invasive diagnostic or therapeutic tasks 1,2 . Biological microorganisms represent the natural inspiration for this vision. For instance, microorganisms successfully swim and move through a variety of fluids and tissues.Locomotion in this regime, where viscous forces dominate over inertia (low Reynolds number), is only possible through non-reciprocal motions demanding spatiotemporal coordination of multiple actuators 3 . A variety of biological propulsion mechanisms at different scales, from the peristalsis of annelids (Fig. 1a) to the metachrony of ciliates (Fig. 1b), are based on the common principle of travelling waves (Fig. 1c). These emerge from the distributed and self-coordinated action of many independent molecular motors 4,5 .Implementing travelling wave propulsion in an artificial device would require many discrete actuators, each individually addressed and powered in a coordinated fashion (Fig. 1d). The integration of actuators into microrobots that are mobile poses additional hurdles, since power and control need to be distributed without affecting the microrobots' mobility. Existing microscale actuators generally rely on applying external magnetic 6-10 , electric 11 , or optical 12,13 fields globally over the entire workspace. However, these approaches do not permit the spatial selectivity required to independently address individual actuators within a micro-device. Nevertheless, complex non-reciprocal motion patterns have been achieved by carefully engineering the response of different regions in a device to a spatially uniform external field 13,14 .The drawback is that this complicates the fabrication process, inhibits down-scaling and constrains the device to a single predefined behaviour. These challenges mean that most artificial microrobots actually have no actuators. Rather...

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots

et al. 2016

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“…A drug delivery device was developed by Iacovacci et al that utilizes external magnetic fields to propel a millimeter-sized robot toward a target region (e.g., spinal, urinary system, ovary, etc. ), while intermagnetic forces are exploited to trigger drug release from a drug-loaded hydrogel [91].…”

Section: General Medical Purposementioning

confidence: 99%

Magnetically driven medical devices: a review

Sliker

Ciuti

Rentschler

et al. 2015

Expert Review of Medical Devices

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A widely accepted definition of a medical device is an instrument or apparatus that is used to diagnose, prevent or treat disease. Medical devices take a broad range of forms and utilize various methods to operate, such as physical, mechanical or thermal. Of particular interest in this paper are the medical devices that utilize magnetic field sources to operate. The exploitation of magnetic fields to operate or drive medical devices has become increasingly popular due to interesting characteristics of magnetic fields that are not offered by other phenomena, such as mechanical contact, hydrodynamics and thermodynamics. Today, there is a wide range of magnetically driven medical devices purposed for different anatomical regions of the body. A review of these devices is presented and organized into two groups: permanent magnetically driven devices and electromagnetically driven devices. Within each category, the discussion will be further segregated into anatomical regions (e.g., gastrointestinal, ocular, abdominal, thoracic, etc.).

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“…cells or drugs). [1,[11][12][13][14][15][16][17] Some of these micromotors have already been examined in ex vivo and in vivo environments. However, there are still significant limitations when steering single or swarms of MNRs in living organisms, [2] in particular when the intended application and micromotor type require high spatiotemporal resolution with precise anatomical positioning.…”

Section: Introductionmentioning

confidence: 99%

In vivo imaging of swimming micromotors using hybrid high-frequency ultrasound and photoacoustic imaging

Aziz

Holthof

Meyer

et al. 2020

Preprint

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The fast evolution of medical micro-and nanorobots in the endeavor to perform non-invasive medical operations in living organisms boosted the use of diverse medical imaging techniques in the last years. Among those techniques, photoacoustic (PA) tomography has shown to be promising for the imaging of microrobots in deep-tissue (ex vivo and in vivo), as it possesses the molecular specificity of optical techniques and the penetration depth of ultrasound imaging.However, the precise maneuvering and function control of microrobots, in particular in living organisms, demand the combination of both anatomical and functional imaging methods.Therefore, herein, we report the use of a hybrid High-Frequency Ultrasound (HFUS) and PA imaging system for the real-time tracking of magnetically driven micromotors (single and swarms) in phantoms, ex vivo, and in vivo (in mice bladder and uterus), envisioning their application for targeted drug-delivery.

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Untethered magnetic millirobot for targeted drug delivery

Cited by 31 publications

References 41 publications

Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots

Structured light enables biomimetic swimming and versatile locomotion of photoresponsive soft microrobots

Magnetically driven medical devices: a review

In vivo imaging of swimming micromotors using hybrid high-frequency ultrasound and photoacoustic imaging

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