Superparamagnetic Twist‐Type Actuators with Shape‐Independent Magnetic Properties and Surface Functionalization for Advanced Biomedical Applications |
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Authors: | Christian Peters Olgaç Ergeneman Pedro D. Wendel García Michelle Müller Salvador Pané Bradley J. Nelson Christofer Hierold |
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Affiliation: | 1. Micro and Nanosystems, ETH Zurich, Zurich, Switzerland;2. Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland |
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Abstract: | Directed nanoparticle self‐organization and two‐photon polymerization are combined to enable three‐dimensional soft‐magnetic microactuators with complex shapes and shape‐independent magnetic properties. Based on the proposed approach, single and double twist‐type swimming microrobots with programmed magnetic anisotropy are demonstrated, and their swimming properties in DI‐water are characterized. The fabricated devices are actuated using weak rotating magnetic fields and are capable of performing wobble‐free corkscrew propulsion. Single twist‐type actuators possess an increase in surface area in excess of 150% over helical actuators with similar feature size without compromising the forward velocity of over one body length per second. A generic and facile combination of glycine grafting and subsequent protein immobilization exploits the actuator's increased surface area, providing for a swimming microrobotic platform with enhanced load capacity desirable for future biomedical applications. Successful surface modification is confirmed by FITC fluorescence. |
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Keywords: | superparamagnetic actuators magnetic easy axis two‐photon polymerization surface functionalization biomedical applications |
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