Microrobots for Minimally Invasive Medicine

Nelson, Bradley J.; Kaliakatsos, I.; Abbott, Jake J.

doi:10.1146/annurev-bioeng-010510-103409

Cited by 1,717 publications

(1,311 citation statements)

References 120 publications

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“…Moreover, the similarities in fluid physics of swimmers across different species,46 from bacteria to parasites, make these findings broadly applicable to other motile microorganisms. In fact, many such active swimmers across diverse biological systems have been an inspiration for the design of artificial micrometer‐scale flagellar systems including biohybrid microrobots,47, 48, 49, 50, 51, 52 and we also envision broad applications of our findings in areas such as medical diagnosis,53 biosensing,54 and targeted drug delivery 55…”

Section: Resultsmentioning

confidence: 95%

Guidance and Self‐Sorting of Active Swimmers: 3D Periodic Arrays Increase Persistence Length of Human Sperm Selecting for the Fittest

et al. 2017

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Male infertility is a reproductive disease, and existing clinical solutions for this condition often involve long and cumbersome sperm sorting methods, including preprocessing and centrifugation‐based steps. These methods also fall short when sorting for sperm free of reactive oxygen species, DNA damage, and epigenetic aberrations. Although several microfluidic platforms exist, they suffer from structural complexities, i.e., pumps or chemoattractants, setting insurmountable barriers to clinical adoption. Inspired by the natural filter‐like capabilities of the female reproductive tract for sperm selection, a model‐driven design, featuring pillar arrays that efficiently and noninvasively isolate highly motile and morphologically normal sperm, with lower epigenetic global methylation, from raw semen, is presented. The Simple Periodic ARray for Trapping And isolatioN (SPARTAN) created here modulates the directional persistence of sperm, increasing the spatial separation between progressive and nonprogressive motile sperm populations within an unprecedentedly short 10 min assay time. With over 99% motility of sorted sperm, a 5‐fold improvement in morphology, 3‐fold increase in nuclear maturity, and 2–4‐fold enhancement in DNA integrity, SPARTAN offers to standardize sperm selection while eliminating operator‐to‐operator variations, centrifugation, and flow. SPARTAN can also be applied in other areas, including conservation ecology, breeding of farm animals, and design of flagellar microrobots for diagnostics.

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Section: Resultsmentioning

confidence: 95%

Guidance and Self‐Sorting of Active Swimmers: 3D Periodic Arrays Increase Persistence Length of Human Sperm Selecting for the Fittest

et al. 2017

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“…5a and b, respectively). 6,19 The change from tumbling to a corkscrew rotation occurs at a specic stabilization frequency. Such frequency-dependent transition motion behavior is illustrated in ESI Video S1 † for a 400 nm diameter helical nanoswimmer, upon increasing the magnetic eld frequency from 10 to 100 Hz.…”

mentioning

confidence: 99%

Template electrosynthesis of tailored-made helical nanoswimmers

Sattayasamitsathit²,

Dong³

et al. 2014

Nanoscale

148

118

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We demonstrate a template electrosynthesis for large-scale low-cost preparation of remarkably small magnetically driven tailored-made helical nanoswimmers that display efficient propulsion behavior and hold considerable promise for future miniature devices in the human body.The synthesis of nanoscale structures capable of moving in liquids represents a major nanotechnological challenge. [1][2][3][4][5][6] Signicant progress has been made recently towards the fabrication of micro/nanomotors that rely on local chemical fuel 7-9 or on external electrical, 10,11 optical, 12 ultrasound 13,14 and magnetic 15-19 stimuli. Among the different types of micro/ nanomotors, magnetically actuated ones are extremely promising for diverse in vivo biomedical applications owing to their attractive swimming performance. 1,17,19 In particular, helical magnetic micro/nanoswimmers -inspired by bacterial agellum propulsion 20 -transform a rotation around their helical axis into a translation along the helical axis to offer an efficient locomotion behavior. 17,19 However, till recently the large-scale preparation of helical micro/nanostructures has been challenging, since traditional microfabrication techniques -based on the deposition or removal of thin layers of materialhave not been compatible with the preparation of complex three-dimensional (3D) helical micro/nanostructures. 19 The challenges of fabricating 3D helical swimmers have been discussed. 17,19 Several fabrication methods have been proposed recently for addressing these challenges and preparing magnetically actuated helical micro/nanoswimmers. 1,17,19 The rst magnetically driven helical corkscrew-shaped microrobot (2-3 mm in diameter, 30-50 mm long) was fabricated by a selfscrolling technique that combines "top-down" lithographic patterning and a "self-organizing" step. 16,21 Even smaller highly densed helical nano-propellers were prepared in 2009 by glancing angle deposition (GLAD). 22 An attractive top-down 3D laser direct writing (DLW) of magnetic helical micromachines was demonstrated recently by Nelson's group. 23,24 Yet, these routes for fabricating helical micro/nanoswimmers require specialized and expensive instrumentation, and the dimensions of these helical magnetic motors are commonly limited by the resolution of optical lithography.This article describes an effective and simple template electrodeposition approach for the large-scale preparation of extremely small and highly efficient helical magnetic swimmers. For over two decades, template electrosynthesis has been shown to be an attractive approach for the mass production of diverse nanostructures and nanodevices. 25 Such templateassisted electrochemical growth of different nanostructures involves electrodeposition of different materials into the cylindrical nanopores of a host porous membrane template, followed by dissolution of the template. 26,27 The versatility of the template-directed electrodeposition has been shown to be extremely useful for preparing chemically powered nanomotors, including cataly...

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“…3 These artificial micromotors offer a broad range of potential applications ranging from drug delivery, microscale assembly and transport, robotics, to motion-based chemical/biochemical sensing. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] Potential environmental applications of micromotors have grown rapidly in recent years, indicating a myriad of innovative remediation and monitoring applications based on new motion-based phenomena. [19][20][21][22][23][24] Specifically, micromotors that exhibit a concentration dependence of their selfpropulsion velocities could mimic chemotactic search strategies employed by microorganisms in biological settings and hence be used to trace plumes of hazardous chemicals to their source.…”

Section: Introductionmentioning

confidence: 99%

Motion-based threat detection using microrods: experiments and numerical simulations

et al. 2015

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Motion-based chemical sensing using microscale particles has attracted considerable recent attention. In this paper, we report on new experiments and Brownian dynamics simulations that cast light on the dynamics of both passive and active microrods (gold wires and gold-platinum micromotors) in a silver ion gradient. We demonstrate that such microrods can be used for threat detection in the form of a silver ion source, allowing for the determination of both the location of the source and concentration of silver.This threat detection strategy relies on the diffusiophoretic motion of both passive and active microrods in the ionic gradient and on the speed acceleration of the Au-Pt micromotors in the presence of silver ions. A Langevin model describing the microrod dynamics and accounting for all of these effects is presented, and key model parameters are extracted from the experimental data, thereby providing a reliable estimate for the full spatiotemporal distribution of the silver ions in the vicinity of the source.

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Microrobots for Minimally Invasive Medicine

Cited by 1,717 publications

References 120 publications

Guidance and Self‐Sorting of Active Swimmers: 3D Periodic Arrays Increase Persistence Length of Human Sperm Selecting for the Fittest

Guidance and Self‐Sorting of Active Swimmers: 3D Periodic Arrays Increase Persistence Length of Human Sperm Selecting for the Fittest

Template electrosynthesis of tailored-made helical nanoswimmers

Motion-based threat detection using microrods: experiments and numerical simulations

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