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203 results (View BibTeX file of all listed publications)
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Series of Multilinked Caterpillar Track-type Climbing Robots

Lee, G., Kim, H., Seo, K., Kim, J., Sitti, M., Seo, T.

Journal of Field Robotics, November 2014 (article)

Abstract
Climbing robots have been widely applied in many industries involving hard to access, dangerous, or hazardous environments to replace human workers. Climbing speed, payload capacity, the ability to overcome obstacles, and wall-to-wall transitioning are significant characteristics of climbing robots. Here, multilinked track wheel-type climbing robots are proposed to enhance these characteristics. The robots have been developed for five years in collaboration with three universities: Seoul National University, Carnegie Mellon University, and Yeungnam University. Four types of robots are presented for different applications with different surface attachment methods and mechanisms: MultiTank for indoor sites, Flexible caterpillar robot (FCR) and Combot for heavy industrial sites, and MultiTrack for high-rise buildings. The method of surface attachment is different for each robot and application, and the characteristics of the joints between links are designed as active or passive according to the requirement of a given robot. Conceptual design, practical design, and control issues of such climbing robot types are reported, and a proper choice of the attachment methods and joint type is essential for the successful multilink track wheel-type climbing robot for different surface materials, robot size, and computational costs.

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DOI [BibTex]

pi Lee, G., Kim, H., Seo, K., Kim, J., Sitti, M., Seo, T. Series of Multilinked Caterpillar Track-type Climbing Robots Journal of Field Robotics, November 2014 (article)

DOI [BibTex]

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Geckogripper: A soft, inflatable robotic gripper using gecko-inspired elastomer micro-fiber adhesives

Song, S., Majidi, C., Sitti, M.

In Intelligent Robots and Systems (IROS 2014), 2014 IEEE/RSJ International Conference on, pages: 4624-4629, September 2014 (inproceedings)

Abstract
This paper proposes GeckoGripper, a novel soft, inflatable gripper based on the controllable adhesion mechanism of gecko-inspired micro-fiber adhesives, to pick-and-place complex and fragile non-planar or planar parts serially or in parallel. Unlike previous fibrillar structures that use peel angle to control the manipulation of parts, we developed an elastomer micro-fiber adhesive that is fabricated on a soft, flexible membrane, increasing the adaptability to non-planar three-dimensional (3D) geometries and controllability in adhesion. The adhesive switching ratio (the ratio between the maximum and minimum adhesive forces) of the developed gripper was measured to be around 204, which is superior to previous works based on peel angle-based release control methods. Adhesion control mechanism based on the stretch of the membrane and superior adaptability to non-planar 3D geometries enable the micro-fibers to pick-and-place various 3D parts as shown in demonstrations.

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DOI [BibTex]

pi Song, S., Majidi, C., Sitti, M. Geckogripper: A soft, inflatable robotic gripper using gecko-inspired elastomer micro-fiber adhesives In Intelligent Robots and Systems (IROS 2014), 2014 IEEE/RSJ International Conference on, pages: 4624-4629, September 2014 (inproceedings)

DOI [BibTex]

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Segmented molecular design of self-healing proteinaceous materials.

Sariola, V., Pena-Francesch, A., Jung, H., Çetinkaya, M., Pacheco, C., Sitti, M., Demirel, M. C.

Scientific reports, 5, pages: 13482-13482, Nature Publishing Group, July 2014 (article)

Abstract
Hierarchical assembly of self-healing adhesive proteins creates strong and robust structural and interfacial materials, but understanding of the molecular design and structure–property relationships of structural proteins remains unclear. Elucidating this relationship would allow rational design of next generation genetically engineered self-healing structural proteins. Here we report a general self-healing and -assembly strategy based on a multiphase recombinant protein based material. Segmented structure of the protein shows soft glycine- and tyrosine-rich segments with self-healing capability and hard beta-sheet segments. The soft segments are strongly plasticized by water, lowering the self-healing temperature close to body temperature. The hard segments self-assemble into nanoconfined domains to reinforce the material. The healing strength scales sublinearly with contact time, which associates with diffusion and wetting of autohesion. The finding suggests that recombinant structural proteins from heterologous expression have potential as strong and repairable engineering materials.

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DOI [BibTex]

pi Sariola, V., Pena-Francesch, A., Jung, H., Çetinkaya, M., Pacheco, C., Sitti, M., Demirel, M. C. Segmented molecular design of self-healing proteinaceous materials. Scientific reports, 5, pages: 13482-13482, Nature Publishing Group, July 2014 (article)

DOI [BibTex]

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Bio-Hybrid Cell-Based Actuators for Microsystems

Carlsen, R. W., Sitti, M.

Small, 10(19):3831-3851, June 2014 (article)

Abstract
As we move towards the miniaturization of devices to perform tasks at the nano and microscale, it has become increasingly important to develop new methods for actuation, sensing, and control. Over the past decade, bio-hybrid methods have been investigated as a promising new approach to overcome the challenges of scaling down robotic and other functional devices. These methods integrate biological cells with artificial components and therefore, can take advantage of the intrinsic actuation and sensing functionalities of biological cells. Here, the recent advancements in bio-hybrid actuation are reviewed, and the challenges associated with the design, fabrication, and control of bio-hybrid microsystems are discussed. As a case study, focus is put on the development of bacteria-driven microswimmers, which has been investigated as a targeted drug delivery carrier. Finally, a future outlook for the development of these systems is provided. The continued integration of biological and artificial components is envisioned to enable the performance of tasks at a smaller and smaller scale in the future, leading to the parallel and distributed operation of functional systems at the microscale.

pi

DOI [BibTex]

pi Carlsen, R. W., Sitti, M. Bio-Hybrid Cell-Based Actuators for Microsystems Small, 10(19):3831-3851, June 2014 (article)

DOI [BibTex]

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Nanopropellers and Their Actuation in Complex Viscoelastic Media

Schamel, D., Mark, A. G., Gibbs, J. G., Miksch, C., Morozov, K. I., Leshansky, A. M., Fischer, P.

ACS Nano, 8(9):8794-8801, June 2014, Featured cover article. (article)

Abstract
Tissue and biological fluids are complex viscoelastic media with a nanoporous macromolecular structure. Here, we demonstrate that helical nanopropellers can be controllably steered through such a biological gel. The screw-propellers have a filament diameter of about 70 nm and are smaller than previously reported nanopropellers as well as any swimming microorganism. We show that the nanoscrews will move through high-viscosity solutions with comparable velocities to that of larger micropropellers, even though they are so small that Brownian forces suppress their actuation in pure water. When actuated in viscoelastic hyaluronan gels, the nanopropellers appear to have a significant advantage, as they are of the same size range as the gel’s mesh size. Whereas larger helices will show very low or negligible propulsion in hyaluronan solutions, the nanoscrews actually display significantly enhanced propulsion velocities that exceed the highest measured speeds in Newtonian fluids. The nanopropellers are not only promising for applications in the extracellular environment but small enough to be taken up by cells.

Featured cover article.

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Video - Helical Micro and Nanopropellers for Applications in Biological Fluidic Environments link (url) DOI [BibTex]

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Convertor

Fischer, P., Mark, A.

May 2014 (patent)

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[BibTex]

pf Fischer, P., Mark, A. Convertor May 2014 (patent)

[BibTex]

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Fibrillar structures to reduce viscous drag on aerodynamic and hydrodynamic wall surfaces

Castillo, L., Aksak, B., Sitti, M.

March 2014, US Patent App. 14/774,767 (misc)

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[BibTex]

pi Castillo, L., Aksak, B., Sitti, M. Fibrillar structures to reduce viscous drag on aerodynamic and hydrodynamic wall surfaces March 2014, US Patent App. 14/774,767 (misc)

[BibTex]

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The design of microfibers with mushroom-shaped tips for optimal adhesion

Sitti, M., Aksak, B.

February 2014, US Patent App. 14/766,561 (misc)

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[BibTex]

pi Sitti, M., Aksak, B. The design of microfibers with mushroom-shaped tips for optimal adhesion February 2014, US Patent App. 14/766,561 (misc)

[BibTex]

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3D nanofabrication on complex seed shapes using glancing angle deposition

Hyeon-Ho, J., Mark, A. G., Gibbs, J. G., Reindl, T., Waizmann, U., Weis, J., Fischer, P.

In 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS), pages: 437-440, January 2014 (inproceedings)

Abstract
Three-dimensional (3D) fabrication techniques promise new device architectures and enable the integration of more components, but fabricating 3D nanostructures for device applications remains challenging. Recently, we have performed glancing angle deposition (GLAD) upon a nanoscale hexagonal seed array to create a variety of 3D nanoscale objects including multicomponent rods, helices, and zigzags [1]. Here, in an effort to generalize our technique, we present a step-by-step approach to grow 3D nanostructures on more complex nanoseed shapes and configurations than before. This approach allows us to create 3D nanostructures on nanoseeds regardless of seed sizes and shapes.

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DOI [BibTex]

pf Hyeon-Ho, J., Mark, A. G., Gibbs, J. G., Reindl, T., Waizmann, U., Weis, J., Fischer, P. 3D nanofabrication on complex seed shapes using glancing angle deposition In 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS), pages: 437-440, January 2014 (inproceedings)

DOI [BibTex]

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Circular polarization interferometry: circularly polarized modes of cholesteric liquid crystals

Sanchez-Castillo, A., Eslami, S., Giesselmann, F., Fischer, P.

OPTICS EXPRESS, 22(25):31227-31236, 2014 (article)

Abstract
We describe a novel polarization interferometer which permits the determination of the refractive indices for circularly-polarized light. It is based on a Jamin-Lebedeff interferometer, modified with waveplates, and permits us to experimentally determine the refractive indices n(L) and n(R) of the respectively left- and right-circularly polarized modes in a cholesteric liquid crystal. Whereas optical rotation measurements only determine the circular birefringence, i.e. the difference (n(L) - n(R)), the interferometer also permits the determination of their absolute values. We report refractive indices of a cholesteric liquid crystal in the region of selective (Bragg) reflection as a function of temperature. (C) 2014 Optical Society of America

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DOI [BibTex]

pf Sanchez-Castillo, A., Eslami, S., Giesselmann, F., Fischer, P. Circular polarization interferometry: circularly polarized modes of cholesteric liquid crystals OPTICS EXPRESS, 22(25):31227-31236, 2014 (article)

DOI [BibTex]

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Self-Propelling Nanomotors in the Presence of Strong Brownian Forces

Lee, T., Alarcon-Correa, M., Miksch, C., Hahn, K., Gibbs, J. G., Fischer, P.

NANO LETTERS, 14(5):2407-2412, 2014 (article)

Abstract
Motility in living systems is due to an array of complex molecular nanomotors that are essential for the function and survival of cells. These protein nanomotors operate not only despite of but also because of stochastic forces. Artificial means of realizing motility rely on local concentration or temperature gradients that are established across a particle, resulting in slip velocities at the particle surface and thus motion of the particle relative to the fluid. However, it remains unclear if these artificial motors can function at the smallest of scales, where Brownian motion dominates and no actively propelled living organisms can be found. Recently, the first reports have appeared suggesting that the swimming mechanisms of artificial structures may also apply to enzymes that are catalytically active. Here we report a scheme to realize artificial Janus nanoparticles (JNPs) with an overall size that is comparable to that of some enzymes similar to 30 nm. Our JNPs can catalyze the decomposition of hydrogen peroxide to water and oxygen and thus actively move by self-electrophoresis. Geometric anisotropy of the Pt-Au Janus nanoparticles permits the simultaneous observation of their translational and rotational motion by dynamic light scattering. While their dynamics is strongly influenced by Brownian rotation, the artificial Janus nanomotors show bursts of linear ballistic motion resulting in enhanced diffusion.

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DOI [BibTex]

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Shape control in wafer-based aperiodic 3D nanostructures

Hyeon-Ho, J., Mark, A. G., Gibbs, J. G., Reindl, T., Waizmann, U., Weis, J., Fischer, P.

NANOTECHNOLOGY, 25(23), 2014, Cover article. (article)

Abstract
Controlled local fabrication of three-dimensional (3D) nanostructures is important to explore and enhance the function of single nanodevices, but is experimentally challenging. We present a scheme based on e-beam lithography (EBL) written seeds, and glancing angle deposition (GLAD) grown structures to create nanoscale objects with defined shapes but in aperiodic arrangements. By using a continuous sacrificial corral surrounding the features of interest we grow isolated 3D nanostructures that have complex cross-sections and sidewall morphology that are surrounded by zones of clean substrate.

Cover article.

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DOI [BibTex]

pf Hyeon-Ho, J., Mark, A. G., Gibbs, J. G., Reindl, T., Waizmann, U., Weis, J., Fischer, P. Shape control in wafer-based aperiodic 3D nanostructures NANOTECHNOLOGY, 25(23), 2014, Cover article. (article)

DOI [BibTex]

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Active Microrheology of the Vitreous of the Eye applied to Nanorobot Propulsion

Qiu, T., Schamel, D., Mark, A. G., Fischer, P.

In 2014 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA), pages: 3801-3806, IEEE International Conference on Robotics and Automation ICRA, 2014, Best Automation Paper Award – Finalist. (inproceedings)

Abstract
Biomedical applications of micro or nanorobots require active movement through complex biological fluids. These are generally non-Newtonian (viscoelastic) fluids that are characterized by complicated networks of macromolecules that have size-dependent rheological properties. It has been suggested that an untethered microrobot could assist in retinal surgical procedures. To do this it must navigate the vitreous humor, a hydrated double network of collagen fibrils and high molecular-weight, polyanionic hyaluronan macromolecules. Here, we examine the characteristic size that potential robots must have to traverse vitreous relatively unhindered. We have constructed magnetic tweezers that provide a large gradient of up to 320 T/m to pull sub-micron paramagnetic beads through biological fluids. A novel two-step electrical discharge machining (EDM) approach is used to construct the tips of the magnetic tweezers with a resolution of 30 mu m and high aspect ratio of similar to 17:1 that restricts the magnetic field gradient to the plane of observation. We report measurements on porcine vitreous. In agreement with structural data and passive Brownian diffusion studies we find that the unhindered active propulsion through the eye calls for nanorobots with cross-sections of less than 500 nm.

Best Automation Paper Award – Finalist.

pf

[BibTex]

pf Qiu, T., Schamel, D., Mark, A. G., Fischer, P. Active Microrheology of the Vitreous of the Eye applied to Nanorobot Propulsion In 2014 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION (ICRA), pages: 3801-3806, IEEE International Conference on Robotics and Automation ICRA, 2014, Best Automation Paper Award – Finalist. (inproceedings)

[BibTex]

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Swimming by reciprocal motion at low Reynolds number

Qiu, T., Lee, T., Mark, A. G., Morozov, K. I., Muenster, R., Mierka, O., Turek, S., Leshansky, A. M., Fischer, P.

NATURE COMMUNICATIONS, 5, 2014, Max Planck Press Release. (article)

Abstract
Biological microorganisms swim with flagella and cilia that execute nonreciprocal motions for low Reynolds number (Re) propulsion in viscous fluids. This symmetry requirement is a consequence of Purcell's scallop theorem, which complicates the actuation scheme needed by microswimmers. However, most biomedically important fluids are non-Newtonian where the scallop theorem no longer holds. It should therefore be possible to realize a microswimmer that moves with reciprocal periodic body-shape changes in non-Newtonian fluids. Here we report a symmetric `micro-scallop', a single-hinge microswimmer that can propel in shear thickening and shear thinning (non-Newtonian) fluids by reciprocal motion at low Re. Excellent agreement between our measurements and both numerical and analytical theoretical predictions indicates that the net propulsion is caused by modulation of the fluid viscosity upon varying the shear rate. This reciprocal swimming mechanism opens new possibilities in designing biomedical microdevices that can propel by a simple actuation scheme in non-Newtonian biological fluids.

Max Planck Press Release.

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Video - A Swimming Micro-Scallop Video - Winner of the Micro-robotic Design Challenge in Hamlyn Symposium on Medical Robotics DOI [BibTex]

pf Qiu, T., Lee, T., Mark, A. G., Morozov, K. I., Muenster, R., Mierka, O., Turek, S., Leshansky, A. M., Fischer, P. Swimming by reciprocal motion at low Reynolds number NATURE COMMUNICATIONS, 5, 2014, Max Planck Press Release. (article)

Video - A Swimming Micro-Scallop Video - Winner of the Micro-robotic Design Challenge in Hamlyn Symposium on Medical Robotics DOI [BibTex]

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Nanohelices by shadow growth

Gibbs, J. G., Mark, A. G., Lee, T., Eslami, S., Schamel, D., Fischer, P.

NANOSCALE, 6(16):9457-9466, 2014 (article)

Abstract
The helix has remarkable qualities and is prevalent in many fields including mathematics, physics, chemistry, and biology. This shape, which is chiral by nature, is ubiquitous in biology with perhaps the most famous example being DNA. Other naturally occurring helices are common at the nanoscale in the form of protein secondary structures and in various macromolecules. Nanoscale helices exhibit a wide range of interesting mechanical, optical, and electrical properties which can be intentionally engineered into the structure by choosing the correct morphology and material. As technology advances, these fabrication parameters can be fine-tuned and matched to the application of interest. Herein, we focus on the fabrication and properties of nanohelices grown by a dynamic shadowing growth method combined with fast wafer-scale substrate patterning which has a number of distinct advantages. We review the fabrication methodology and provide several examples that illustrate the generality and utility of nanohelices shadow-grown on nanopatterns.

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Video - Fabrication of Designer Nanostructures DOI [BibTex]

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Continuously distributed magnetization profile for millimeter-scale elastomeric undulatory swimming

Diller, E., Zhuang, J., Zhan Lum, G., Edwards, M. R., Sitti, M.

Applied Physics Letters, 104(17):174101, AIP, 2014 (article)

Abstract
We have developed a millimeter-scale magnetically driven swimming robot for untethered motion at mid to low Reynolds numbers. The robot is propelled by continuous undulatory deformation, which is enabled by the distributed magnetization profile of a flexible sheet. We demonstrate control of a prototype device and measure deformation and speed as a function of magnetic field strength and frequency. Experimental results are compared with simple magnetoelastic and fluid propulsion models. The presented mechanism provides an efficient remote actuation method at the millimeter scale that may be suitable for further scaling down in size for microrobotics applications in biotechnology and healthcare

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link (url) DOI [BibTex]

pi Diller, E., Zhuang, J., Zhan Lum, G., Edwards, M. R., Sitti, M. Continuously distributed magnetization profile for millimeter-scale elastomeric undulatory swimming Applied Physics Letters, 104(17):174101, AIP, 2014 (article)

link (url) DOI [BibTex]

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Chiral Nanomagnets

Eslami, S., Gibbs, J. G., Rechkemmer, Y., van Slageren, J., Alarcon-Correa, M., Lee, T., Mark, A. G., Rikken, G. L. J. A., Fischer, P.

ACS PHOTONICS, 1(11):1231-1236, 2014 (article)

Abstract
We report on the enhanced optical properties of chiral magnetic nanohelices with critical dimensions comparable to the ferromagnetic domain size. They are shown to be ferromagnetic at room temperature, have defined chirality, and exhibit large optical activity in the visible as verified by electron microscopy, superconducting quantum interference device (SQUID) magnetometry, natural circular dichroism (NCD), and magnetic circular dichroism (MCD) measurements. The structures exhibit magneto-chiral dichroism (MChD), which directly demonstrates coupling between their structural chirality and magnetism. A chiral nickel (Ni) film consisting of an array of nanohelices similar to 100 nm in length exhibits an MChD anisotropy factor g(MChD) approximate to 10(-4) T-1 at room temperature in a saturation field of similar to 0.2 T, permitting polarization-independent control of the film's absorption properties through magnetic field modulation. This is also the first report of MChD in a material with structural chirality on the order of the wavelength of light, and therefore the Ni nanohelix array is a metamaterial with magnetochiral properties that can be tailored through a dynamic deposition process.

pf

DOI [BibTex]

pf Eslami, S., Gibbs, J. G., Rechkemmer, Y., van Slageren, J., Alarcon-Correa, M., Lee, T., Mark, A. G., Rikken, G. L. J. A., Fischer, P. Chiral Nanomagnets ACS PHOTONICS, 1(11):1231-1236, 2014 (article)

DOI [BibTex]

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Wireless powering of e-swimmers

Roche, J., Carrara, S., Sanchez, J., Lannelongue, J., Loget, G., Bouffier, L., Fischer, P., Kuhn, A.

SCIENTIFIC REPORTS, 4, 2014 (article)

Abstract
Miniaturized structures that can move in a controlled way in solution and integrate various functionalities are attracting considerable attention due to the potential applications in fields ranging from autonomous micromotors to roving sensors. Here we introduce a concept which allows, depending on their specific design, the controlled directional motion of objects in water, combined with electronic functionalities such as the emission of light, sensing, signal conversion, treatment and transmission. The approach is based on electric field-induced polarization, which triggers different chemical reactions at the surface of the object and thereby its propulsion. This results in a localized electric current that can power in a wireless way electronic devices in water, leading to a new class of electronic swimmers (e-swimmers).

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DOI [BibTex]

pf Roche, J., Carrara, S., Sanchez, J., Lannelongue, J., Loget, G., Bouffier, L., Fischer, P., Kuhn, A. Wireless powering of e-swimmers SCIENTIFIC REPORTS, 4, 2014 (article)

DOI [BibTex]

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Swelling and shrinking behaviour of photoresponsive phosphonium-based ionogel microstructures

Czugala, M., O’Connell, C., Blin, C., Fischer, P., Fraser, K. J., Benito-Lopez, F., Diamond, D.

SENSORS AND ACTUATORS B-CHEMICAL, 194, pages: 105-113, 2014 (article)

Abstract
Photoresponsive N-isopropylacrylamide ionogel microstructures are presented in this study. These ionogels are synthesised using phosphonium based room temperature ionic liquids, together with the photochromic compound benzospiropyran. The microstructures can be actuated using light irradiation, facilitating non-contact and non-invasive operation. For the first time, the characterisation of the swelling and shrinking behaviour of several photopatterned ionogel microstructures is presented and the influence of surface-area-to-volume ratio on the swelling kinetics is evaluated. It was found that the swelling and shrinking behaviour of the ionogels is strongly dependent on the nature of the ionic liquid. In particular, the {[}P-6,P-6,P-6,P-14]{[}NTf2] ionogel exhibits the greatest degree of swelling, reaching up to 180\% of its initial size, and the fastest shrinkage rate (k(sh) = 29 +/- 4 x 10(-2) s(-1)). (C) 2014 Elsevier B. V. All rights reserved.

pf

DOI [BibTex]

pf Czugala, M., O’Connell, C., Blin, C., Fischer, P., Fraser, K. J., Benito-Lopez, F., Diamond, D. Swelling and shrinking behaviour of photoresponsive phosphonium-based ionogel microstructures SENSORS AND ACTUATORS B-CHEMICAL, 194, pages: 105-113, 2014 (article)

DOI [BibTex]

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Biopsy using a Magnetic Capsule Endoscope Carrying, Releasing and Retrieving Untethered Micro-Grippers

Yim, S., Gultepe, E., Gracias, D. H., Sitti, M.

IEEE Trans. on Biomedical Engineering, 61(2):513-521, IEEE, 2014 (article)

pi

Project Page [BibTex]

pi Yim, S., Gultepe, E., Gracias, D. H., Sitti, M. Biopsy using a Magnetic Capsule Endoscope Carrying, Releasing and Retrieving Untethered Micro-Grippers IEEE Trans. on Biomedical Engineering, 61(2):513-521, IEEE, 2014 (article)

Project Page [BibTex]

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Investigation of tip current and normal force measured simultaneously during local oxidation of titanium using dual-mode scanning probe microscopy

Ozcan, O., Hu, W., Sitti, M., Bain, J., Ricketts, D.

IET Micro \& Nano Letters, 9(5):332-336, IET, 2014 (article)

pi

[BibTex]

pi Ozcan, O., Hu, W., Sitti, M., Bain, J., Ricketts, D. Investigation of tip current and normal force measured simultaneously during local oxidation of titanium using dual-mode scanning probe microscopy IET Micro \& Nano Letters, 9(5):332-336, IET, 2014 (article)

[BibTex]

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Three-dimensional robotic manipulation and transport of micro-scale objects by a magnetically driven capillary micro-gripper

Giltinan, J., Diller, E., Mayda, C., Sitti, M.

In Robotics and Automation (ICRA), 2014 IEEE International Conference on, pages: 2077-2082, 2014 (inproceedings)

pi

Project Page [BibTex]

pi Giltinan, J., Diller, E., Mayda, C., Sitti, M. Three-dimensional robotic manipulation and transport of micro-scale objects by a magnetically driven capillary micro-gripper In Robotics and Automation (ICRA), 2014 IEEE International Conference on, pages: 2077-2082, 2014 (inproceedings)

Project Page [BibTex]

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SoftCubes: Stretchable and self-assembling three-dimensional soft modular matter

Yim, S., Sitti, M.

The International Journal of Robotics Research, 33(8):1083-1097, SAGE Publications Sage UK: London, England, 2014 (article)

pi

Project Page [BibTex]

pi Yim, S., Sitti, M. SoftCubes: Stretchable and self-assembling three-dimensional soft modular matter The International Journal of Robotics Research, 33(8):1083-1097, SAGE Publications Sage UK: London, England, 2014 (article)

Project Page [BibTex]

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Bio-Hybrid Cell-Based Actuators for Microsystems

Carlsen, Rika Wright, Sitti, Metin

Small, 10(19):3831-3851, 2014 (article)

Abstract
As we move towards the miniaturization of devices to perform tasks at the nano and microscale, it has become increasingly important to develop new methods for actuation, sensing, and control. Over the past decade, bio-hybrid methods have been investigated as a promising new approach to overcome the challenges of scaling down robotic and other functional devices. These methods integrate biological cells with artificial components and therefore, can take advantage of the intrinsic actuation and sensing functionalities of biological cells. Here, the recent advancements in bio-hybrid actuation are reviewed, and the challenges associated with the design, fabrication, and control of bio-hybrid microsystems are discussed. As a case study, focus is put on the development of bacteria-driven microswimmers, which has been investigated as a targeted drug delivery carrier. Finally, a future outlook for the development of these systems is provided. The continued integration of biological and artificial components is envisioned to enable the performance of tasks at a smaller and smaller scale in the future, leading to the parallel and distributed operation of functional systems at the microscale.

pi

link (url) DOI Project Page [BibTex]

pi Carlsen, Rika Wright, Sitti, Metin Bio-Hybrid Cell-Based Actuators for Microsystems Small, 10(19):3831-3851, 2014 (article)

link (url) DOI Project Page [BibTex]

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Schalten der Polarität magnetischer Vortexkerne durch eine Zwei-Frequenzen Anregung und mittels direkter Einkopplung eines Stroms

Sproll, M.

Universität Stuttgart, Stuttgart (und Cuvillier Verlag, Göttingen), Stuttgart, 2014 (phdthesis)

mms

[BibTex]

mms Sproll, M. Schalten der Polarität magnetischer Vortexkerne durch eine Zwei-Frequenzen Anregung und mittels direkter Einkopplung eines Stroms Universität Stuttgart, Stuttgart (und Cuvillier Verlag, Göttingen), Stuttgart, 2014 (phdthesis)

[BibTex]

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Efflorescence upon humidification? X-ray microspectroscopic in situ observation of changes in aerosol microstructure and phase state upon hydration

Pöhlker, C., Saturno, J., Krüger, M. L., Förster, J. D., Weigand, M., Wiedemann, K. T., Bechtel, M., Artaxo, P., Andreae, M. O.

{Geophysical Research Letters}, 41(10):3681-3689, American Geophysical Union, Washington, D.C., 2014 (article)

mms

DOI [BibTex]

mms Pöhlker, C., Saturno, J., Krüger, M. L., Förster, J. D., Weigand, M., Wiedemann, K. T., Bechtel, M., Artaxo, P., Andreae, M. O. Efflorescence upon humidification? X-ray microspectroscopic in situ observation of changes in aerosol microstructure and phase state upon hydration {Geophysical Research Letters}, 41(10):3681-3689, American Geophysical Union, Washington, D.C., 2014 (article)

DOI [BibTex]

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Investigation of cellular microstructure and enhanced coercivity in sputtered Sm2(CoCuFeZr)17 film

Bhatt, R., Bhatt, P., Schütz, G.

{Journal of Applied Physics}, 115(10), American Institute of Physics, New York, NY, 2014 (article)

mms

DOI [BibTex]

mms Bhatt, R., Bhatt, P., Schütz, G. Investigation of cellular microstructure and enhanced coercivity in sputtered Sm2(CoCuFeZr)17 film {Journal of Applied Physics}, 115(10), American Institute of Physics, New York, NY, 2014 (article)

DOI [BibTex]

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Detecting magnetic flux distributions in superconductors with polarized x-rays

Stahl, C., Audehm, P., Gräfe, J., Ruoß, S., Weigand, M., Schmidt, M., Treiber, S., Bechtel, M., Goering, E., Schütz, G., Albrecht, J.

{Physical Review B}, 90(10), American Physical Society, Woodbury, NY, 2014 (article)

mms

DOI [BibTex]

mms Stahl, C., Audehm, P., Gräfe, J., Ruoß, S., Weigand, M., Schmidt, M., Treiber, S., Bechtel, M., Goering, E., Schütz, G., Albrecht, J. Detecting magnetic flux distributions in superconductors with polarized x-rays {Physical Review B}, 90(10), American Physical Society, Woodbury, NY, 2014 (article)

DOI [BibTex]

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Spatial degradation mapping and component-wise degradation tracking in polymer-fullerene blends

Pedersen, E. B. B., Tromholt, T., Madsen, M. V., Böttiger, A. P. L., Weigand, M., Krebs, F. C., Andreasen, J. W.

{Journal of Materials Chemistry C}, 2(26):5176-5182, Royal Society of Chemistry, Cambridge, UK, 2014 (article)

mms

DOI [BibTex]

mms Pedersen, E. B. B., Tromholt, T., Madsen, M. V., Böttiger, A. P. L., Weigand, M., Krebs, F. C., Andreasen, J. W. Spatial degradation mapping and component-wise degradation tracking in polymer-fullerene blends {Journal of Materials Chemistry C}, 2(26):5176-5182, Royal Society of Chemistry, Cambridge, UK, 2014 (article)

DOI [BibTex]

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Vortex core reversal due to spin wave interference

Bauer, H. G., Sproll, M., Back, C. H., Woltersdorf, G.

{Physical Review Letters}, 112, American Physical Society, Woodbury, N.Y., 2014 (article)

mms

DOI [BibTex]

mms Bauer, H. G., Sproll, M., Back, C. H., Woltersdorf, G. Vortex core reversal due to spin wave interference {Physical Review Letters}, 112, American Physical Society, Woodbury, N.Y., 2014 (article)

DOI [BibTex]

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Increasing the sensor performance using Au modified high temperature superconducting YBa2Cu3O7-delta thin films

Katzer, C., Stahl, C., Michalowski, P., Treiber, S., Westernhausen, M., Schmidl, F., Seidel, P., Schütz, G., Albrecht, J.

In 507, IOP Pub., Genova, Italy, 2014 (inproceedings)

mms

DOI [BibTex]

mms Katzer, C., Stahl, C., Michalowski, P., Treiber, S., Westernhausen, M., Schmidl, F., Seidel, P., Schütz, G., Albrecht, J. Increasing the sensor performance using Au modified high temperature superconducting YBa2Cu3O7-delta thin films In 507, IOP Pub., Genova, Italy, 2014 (inproceedings)

DOI [BibTex]

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Understanding the adsorption mechanism of noble gases Kr and Xe in CPO-27-Ni, CPO-27-Mg, and ZIF-8

Magdysyuk, O. V., Adams, F., Liermann, H., Spanopoulos, I., Trikalitis, P. N., Hirscher, M., Morris, R. E., Duncan, M. J., McCormick, L. J., Dinnebier, R. E.

{Physical Chemistry Chemical Physics}, 16(43):23908-23914, Royal Society of Chemistry, Cambridge, England, 2014 (article)

mms

DOI [BibTex]

mms Magdysyuk, O. V., Adams, F., Liermann, H., Spanopoulos, I., Trikalitis, P. N., Hirscher, M., Morris, R. E., Duncan, M. J., McCormick, L. J., Dinnebier, R. E. Understanding the adsorption mechanism of noble gases Kr and Xe in CPO-27-Ni, CPO-27-Mg, and ZIF-8 {Physical Chemistry Chemical Physics}, 16(43):23908-23914, Royal Society of Chemistry, Cambridge, England, 2014 (article)

DOI [BibTex]

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Addressing of Micro-robot Teams and Non-contact Micro-manipulation

Diller, E., Ye, Z., Giltinan, J., Sitti, M.

In Small-Scale Robotics. From Nano-to-Millimeter-Sized Robotic Systems and Applications, pages: 28-38, Springer Berlin Heidelberg, 2014 (incollection)

pi

Project Page [BibTex]

pi Diller, E., Ye, Z., Giltinan, J., Sitti, M. Addressing of Micro-robot Teams and Non-contact Micro-manipulation In Small-Scale Robotics. From Nano-to-Millimeter-Sized Robotic Systems and Applications, pages: 28-38, Springer Berlin Heidelberg, 2014 (incollection)

Project Page [BibTex]

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Staying sticky: contact self-cleaning of gecko-inspired adhesives

Mengüç, Y., Röhrig, M., Abusomwan, U., Hölscher, H., Sitti, M.

Journal of The Royal Society Interface, 11(94):20131205, The Royal Society, 2014 (article)

pi

Project Page [BibTex]

pi Mengüç, Y., Röhrig, M., Abusomwan, U., Hölscher, H., Sitti, M. Staying sticky: contact self-cleaning of gecko-inspired adhesives Journal of The Royal Society Interface, 11(94):20131205, The Royal Society, 2014 (article)

Project Page [BibTex]

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Dynamic Trapping and Two-Dimensional Transport of Swimming Microorganisms Using a Rotating Magnetic Micro-Robot

Ye, Z., Sitti, M.

Lab on a Chip, 14(13):2177-2182, Royal Society of Chemistry, 2014 (article)

pi

Project Page [BibTex]

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STRIDE II: a water strider-inspired miniature robot with circular footpads

Ozcan, O., Wang, H., Taylor, J. D., Sitti, M.

International Journal of Advanced Robotic Systems, 11(6):85, SAGE Publications Sage UK: London, England, 2014 (article)

pi

[BibTex]

pi Ozcan, O., Wang, H., Taylor, J. D., Sitti, M. STRIDE II: a water strider-inspired miniature robot with circular footpads International Journal of Advanced Robotic Systems, 11(6):85, SAGE Publications Sage UK: London, England, 2014 (article)

[BibTex]

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Soft Grippers Using Micro-Fibrillar Adhesives for Transfer Printing

Song, S., Sitti, M.

Advanced Materials, 26(28):4901-4906, 2014 (article)

pi

[BibTex]

pi Song, S., Sitti, M. Soft Grippers Using Micro-Fibrillar Adhesives for Transfer Printing Advanced Materials, 26(28):4901-4906, 2014 (article)

[BibTex]

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Dual Execution of Optimized Contact Interaction Trajectories

Toussaint, M., Ratliff, N., Bohg, J., Righetti, L., Englert, P., Schaal, S.

In 2014 IEEE/RSJ Conference on Intelligent Robots and Systems, pages: 47-54, IEEE, Chicago, USA, 2014 (inproceedings)

Abstract
Efficient manipulation requires contact to reduce uncertainty. The manipulation literature refers to this as funneling: a methodology for increasing reliability and robustness by leveraging haptic feedback and control of environmental interaction. However, there is a fundamental gap between traditional approaches to trajectory optimization and this concept of robustness by funneling: traditional trajectory optimizers do not discover force feedback strategies. From a POMDP perspective, these behaviors could be regarded as explicit observation actions planned to sufficiently reduce uncertainty thereby enabling a task. While we are sympathetic to the full POMDP view, solving full continuous-space POMDPs in high-dimensions is hard. In this paper, we propose an alternative approach in which trajectory optimization objectives are augmented with new terms that reward uncertainty reduction through contacts, explicitly promoting funneling. This augmentation shifts the responsibility of robustness toward the actual execution of the optimized trajectories. Directly tracing trajectories through configuration space would lose all robustness-dual execution achieves robustness by devising force controllers to reproduce the temporal interaction profile encoded in the dual solution of the optimization problem. This work introduces dual execution in depth and analyze its performance through robustness experiments in both simulation and on a real-world robotic platform.

am mg

link (url) DOI [BibTex]

am mg Toussaint, M., Ratliff, N., Bohg, J., Righetti, L., Englert, P., Schaal, S. Dual Execution of Optimized Contact Interaction Trajectories In 2014 IEEE/RSJ Conference on Intelligent Robots and Systems, pages: 47-54, IEEE, Chicago, USA, 2014 (inproceedings)

link (url) DOI [BibTex]

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Vortex-Kern-Korrelation in gekoppelten Systemen

Jüllig, P.

Universität Stuttgart, Stuttgart, 2014 (phdthesis)

mms

link (url) [BibTex]

mms Jüllig, P. Vortex-Kern-Korrelation in gekoppelten Systemen Universität Stuttgart, Stuttgart, 2014 (phdthesis)

link (url) [BibTex]

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Unidirectional sub-100-ps magnetic vortex core reversal

Noske, M., Gangwar, A., Stoll, H., Kammerer, M., Sproll, M., Dieterle, G., Weigand, M., Fähnle, M., Woltersdorf, G., Back, C. H., Schütz, G.

{Physical Review B}, 90(10), American Physical Society, Woodbury, NY, 2014 (article)

mms

DOI [BibTex]

mms Noske, M., Gangwar, A., Stoll, H., Kammerer, M., Sproll, M., Dieterle, G., Weigand, M., Fähnle, M., Woltersdorf, G., Back, C. H., Schütz, G. Unidirectional sub-100-ps magnetic vortex core reversal {Physical Review B}, 90(10), American Physical Society, Woodbury, NY, 2014 (article)

DOI [BibTex]

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Domain wall transformations and hopping in La0.7Sr0.3MnO3 nanostructures imaged with high resolution x-ray magnetic microscopy

Finizio, S., Foerster, M., Krüger, B., Vaz, C. A. F., Miyawaki, T., Mawass, M. A., Pena, L., Méchin, L., Hühn, S., Moshnyaga, V., Büttner, F., Bisig, A., Le Guyader, L., El Moussaoui, S., Valencia, S., Kronast, F., Eisebitt, S., Kläui, M.

{Journal of Physics: Condensed Matter}, 26(45), IOP Publishing, Bristol, 2014 (article)

mms

DOI [BibTex]

mms Finizio, S., Foerster, M., Krüger, B., Vaz, C. A. F., Miyawaki, T., Mawass, M. A., Pena, L., Méchin, L., Hühn, S., Moshnyaga, V., Büttner, F., Bisig, A., Le Guyader, L., El Moussaoui, S., Valencia, S., Kronast, F., Eisebitt, S., Kläui, M. Domain wall transformations and hopping in La0.7Sr0.3MnO3 nanostructures imaged with high resolution x-ray magnetic microscopy {Journal of Physics: Condensed Matter}, 26(45), IOP Publishing, Bristol, 2014 (article)

DOI [BibTex]

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Tunable eigenmodes of coupled magnetic vortex oscillators

Hänze, M., Adolff, C. F., Weigand, M., Meier, G.

{Applied Physics Letters}, 104(18), American Institute of Physics, Melville, NY, 2014 (article)

mms

DOI [BibTex]

mms Hänze, M., Adolff, C. F., Weigand, M., Meier, G. Tunable eigenmodes of coupled magnetic vortex oscillators {Applied Physics Letters}, 104(18), American Institute of Physics, Melville, NY, 2014 (article)

DOI [BibTex]

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Domain wall pinning in ultra-narrow electromigrated break junctions

Reeve, R. M., Loescher, A., Mawass, M.-A., Hoffmann-Vogel, R., Kläui, M.

{Journal of Physics: Condensed Matter}, 26(47), IOP Publishing, Bristol, 2014 (article)

mms

DOI [BibTex]

mms Reeve, R. M., Loescher, A., Mawass, M.-A., Hoffmann-Vogel, R., Kläui, M. Domain wall pinning in ultra-narrow electromigrated break junctions {Journal of Physics: Condensed Matter}, 26(47), IOP Publishing, Bristol, 2014 (article)

DOI [BibTex]

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Highly effective hydrogen isotope separation in nanoporous metal-organic framworks with open metal sites: Direct measurement and theoretical analysis

Oh, H., Savchenko, I., Mavrandonakis, A., Heine, T., Hirscher, M.

{ACS Nano}, 8(1):761-770, American Chemical Society, Washington, DC, 2014 (article)

mms

DOI [BibTex]

mms Oh, H., Savchenko, I., Mavrandonakis, A., Heine, T., Hirscher, M. Highly effective hydrogen isotope separation in nanoporous metal-organic framworks with open metal sites: Direct measurement and theoretical analysis {ACS Nano}, 8(1):761-770, American Chemical Society, Washington, DC, 2014 (article)

DOI [BibTex]

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Stabilization of the dissipation-free current transport in inhomogeneous MgB2 thin films

Treiber, S., Stahl, C., Schütz, G., Soltan, S., Albrecht, J.

{Physica C}, 506, pages: 1-5, North-Holland, Amsterdam, 2014 (article)

mms

DOI [BibTex]

mms Treiber, S., Stahl, C., Schütz, G., Soltan, S., Albrecht, J. Stabilization of the dissipation-free current transport in inhomogeneous MgB2 thin films {Physica C}, 506, pages: 1-5, North-Holland, Amsterdam, 2014 (article)

DOI [BibTex]

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Thermal conductivity of mechanically joined semiconducting/metal nanomembrane superlattices

Grimm, D., Wilson, R. B., Teshome, B., Gorantla, S., Rümmeli, M. H., Bublat, T., Zallo, E., Li, G., Cahill, D. G., Schmidt, O. G.

{Nano Letters}, 14(5):2387-2393, American Chemical Society, Washington, DC, 2014 (article)

mms

DOI [BibTex]

mms Grimm, D., Wilson, R. B., Teshome, B., Gorantla, S., Rümmeli, M. H., Bublat, T., Zallo, E., Li, G., Cahill, D. G., Schmidt, O. G. Thermal conductivity of mechanically joined semiconducting/metal nanomembrane superlattices {Nano Letters}, 14(5):2387-2393, American Chemical Society, Washington, DC, 2014 (article)

DOI [BibTex]

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Can DC motors directly drive flapping wings at high frequency and large wing strokes?

Campolo, D., Azhar, M., Lau, G., Sitti, M.

IEEE/ASME Trans. on Mechatronics, 19(1):109-120, 2014 (article)

pi

[BibTex]

pi Campolo, D., Azhar, M., Lau, G., Sitti, M. Can DC motors directly drive flapping wings at high frequency and large wing strokes? IEEE/ASME Trans. on Mechatronics, 19(1):109-120, 2014 (article)

[BibTex]

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Magnetic steering control of multi-cellular bio-hybrid microswimmers

Carlsen, R. W., Edwards, M. R., Zhuang, J., Pacoret, C., Sitti, M.

Lab on a Chip, 14(19):3850-3859, Royal Society of Chemistry, 2014 (article)

pi

Project Page [BibTex]

pi Carlsen, R. W., Edwards, M. R., Zhuang, J., Pacoret, C., Sitti, M. Magnetic steering control of multi-cellular bio-hybrid microswimmers Lab on a Chip, 14(19):3850-3859, Royal Society of Chemistry, 2014 (article)

Project Page [BibTex]