Self-Assembled Three Dimensional Radio Frequency (RF) Shielded Containers for Cell Encapsulation

Gimi, Barjor; Leong, Timothy G.; Gu, Zhiyong; Yang, Michael T.; Artemov, Dmitri; Bhujwalla, Zaver M.; Gracias, David H.

doi:10.1007/s10544-005-6076-9

Cited by 64 publications

(64 citation statements)

References 31 publications

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“…Our microgrippers represent an image-guided platform, and techniques such as magnetic resonance imaging or computed tomography will be needed for in vivo guidance. One highlight here is that our microgrippers are metallic; hence, these structures can be easily imaged by using magnetic resonance techniques (33) and specifically wirelessly heated by using electromagnetic fields (34). Another possible complication is that the grippers may become lodged in tissue before reaching the target destination, though we have observed, remarkably, that the grippers can be moved over large distances over certain types of tissue without becoming entangled (Fig.…”

mentioning

confidence: 89%

Tetherless thermobiochemically actuated microgrippers

Leong¹,

Randall

Benson³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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We demonstrate mass-producible, tetherless microgrippers that can be remotely triggered by temperature and chemicals under biologically relevant conditions. The microgrippers use a selfcontained actuation response, obviating the need for external tethers in operation. The grippers can be actuated en masse, even while spatially separated. We used the microgrippers to perform diverse functions, such as picking up a bead on a substrate and the removal of cells from tissue embedded at the end of a capillary (an in vitro biopsy).actuator ͉ biochemical ͉ robotics ͉ thin films B iological function in nature is often achieved by autonomous organisms and cellular components triggered en masse by relatively benign cues, such as small temperature changes and biochemicals. These cues activate a particular response, even among large populations of spatially separated biological components. Chemically triggered activity is also often highly specific and selective in biological machinery. Additionally, mobility of autonomous biological entities, such as pathogens and cells, enables easy passage through narrow conduits and interstitial spaces.As a step toward the construction of autonomous microtools, we describe mass-producible, mobile, thermobiochemically actuated microgrippers. The microgrippers can be remotely actuated when exposed to temperatures Ͼ40°C or selected chemicals. The temperature trigger is in the range experienced by the human body at the onset of a moderate-to-high fever, and the chemical triggers include biologically benign reagents, such as cell media. Using these microgrippers, we achieved a diverse set of functions, such as picking up beads off substrates and removing cells from tissue samples.Conventional microgrippers are usually tethered and actuated by mechanical or electrical signals (1-6). Recently developed actuation mechanisms using pneumatic (7), thermal (8), and electrochemical triggers (9, 10) have also used tethered operation. Because the functional response of currently available microgrippers is usually controlled through external wires or tubes, direct connections need to be made between the gripper and the control unit. These connections restrict device miniaturization and maneuverability. For example, a simple task such as the retrieval of an object from a tube is challenging at the millimeter and submillimeter scale, because tethered microgrippers must be threaded through the tube. Moreover, many of the schemes used to drive actuation in microscale tools use biologically incompatible cues, such as high temperature or nonaqueous media, which limit their utility. There are novel, untethered tools based on shape memory alloys that use low temperature heating, but they have limited mobility and must rely solely on thermal actuation (11,12). The ability of our gripper design to use biochemical actuation, in addition to thermal actuation, represents a paradigm shift in engineering and suggests a strategy for designing mobile microtools that function in a variety of environments with high specif...

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mentioning

confidence: 89%

Tetherless thermobiochemically actuated microgrippers

Leong¹,

Randall

Benson³

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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383

321

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“…Gagler [21] and Gracias et al [23][24][25][26][27][28][29][30][31] showed that the surface tension of evaporating drop of liquid is sufficient to pull the walls of the photolithographically defined thin film patterns together and form various figures, such as boxes or pyramids with the size of several micrometers. These patterns typically consist of more rigid areas connected by thinner areas, which serve as hinges, when the thicker walls fold.…”

Section: Surface Tensionmentioning

confidence: 99%

“…Examples of self-folding micro-origami structures (left and middle picture reproduced with permission from Ref. [21] and the right picture from [23]). …”

Section: Surface Tensionmentioning

confidence: 99%

“…First of all, the micro-origami methods are capable of fabricating biomimetic materials. Magnetic materials are envisioned as candidates for targeted drug delivery [23]. Different magnetic cages [21,23] can be loaded with drugs, dragged with the help of magnetic force to the infected organs, and released in the location where they are the most effective.…”

Section: Prospective Applicationsmentioning

confidence: 99%

“…Magnetic materials are envisioned as candidates for targeted drug delivery [23]. Different magnetic cages [21,23] can be loaded with drugs, dragged with the help of magnetic force to the infected organs, and released in the location where they are the most effective. The targeted delivery of drugs can be achieved with the assistance of microswimmers [16,66], which are able to move against blood stream.…”

Section: Prospective Applicationsmentioning

confidence: 99%

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Magnetic Micro-Origami

Małkiński¹,

Eskandari²

2016

Magnetic Materials

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Microscopic origami figures can be created from thin film patterns using surface tension of liquids or residual stresses in thin films. The curvature of the structures, direction of bending, twisting, and folding of the patterns can be controlled by their shape, thickness, and elastic properties and by the strength of the residual stresses. Magnetic materials used for micro-and nano-origami structures play an essential role in many applications. Magnetic force due to applied magnetic field can be used for remote actuation of microrobots. It can also be used in targeted drug delivery to direct cages loaded with drugs or microswimmers to transport drugs to specific organs. Magnetoelastic properties of free-standing micro-origami patterns can serve for stress or magnetic field sensing. Also, the stress-induced anisotropy and magnetic shape anisotropy provide a convenient method of tuning magnetic properties by designing a shape of the microorigami figures instead of varying the composition of the films. Micro-origami figures can also serve as building blocks for two-and three-dimensional meta-materials with unique properties such as negative index of refraction. Micro-origami techniques provide a powerful method of self-assembly of magnetic circuits and integrating them with microelectro-mechanical systems or other functional devices.

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