Superparamagnetic Twist-Type Actuators with Shape-Independent Magnetic Properties and Surface Functionalization for Advanced Biomedical Applications

摘要

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.