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2020


Acoustofluidic Tweezers for the 3D Manipulation of Microparticles
Acoustofluidic Tweezers for the 3D Manipulation of Microparticles

Guo, X., Ma, Z., Goyal, R., Jeong, M., Pang, W., Fischer, P., Dian, X., Qiu, T.

In 2020 IEEE International Conference on Robotics and Automation (ICRA),, Febuary 2020 (conference)

Abstract
Non-contact manipulation is of great importance in the actuation of micro-robotics. It is challenging to contactless manipulate micro-scale objects over large spatial distance in fluid. Here, we describe a novel approach for the dynamic position control of microparticles in three-dimensional (3D) space, based on high-speed acoustic streaming generated by a micro-fabricated gigahertz transducer. Due to the vertical lifting force and the horizontal centripetal force generated by the streaming, microparticles are able to be stably trapped at a position far away from the transducer surface, and to be manipulated over centimeter distance in all three directions. Only the hydrodynamic force is utilized in the system for particle manipulation, making it a versatile tool regardless the material properties of the trapped particle. The system shows high reliability and manipulation velocity, revealing its potentials for the applications in robotics and automation at small scales.

[BibTex]

2020

[BibTex]


Convertor
Convertor

Fischer, P., Mark, A.

May 2014 (patent)

[BibTex]

[BibTex]


3D nanofabrication on complex seed shapes using glancing angle deposition
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.

DOI [BibTex]

DOI [BibTex]


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

[BibTex]

[BibTex]