Fabrication and performance evaluation of magnetically driven double curved conical ribbon micro-helical robot

In this research, a magnetically driven double curved conical ribbon micro-helical robot was proposed to improve the swimming stability and swimming performance. Its swimming performance as well as mag-netization characteristics were analyzed by fluid dynamics simulation. Meanwhile, a transverse bidirec-tional fold-line scanning method was proposed to fabricate the designed microrobots via voxel-modulation two-photon polymerization microfabrication technology. After optimizing the machining parameters, the length dimension error of the double curved conical ribbon micro-helical robot could be further reduced to less than 1%. Furthermore, a conical rotating three-dimensional uniform magnetic field was established to drive the microrobots. Microrobot driven experiment of the conical rotating three-dimensional uniform magnetic field was conducted and compared with the planar uniform mag-netic field. It is proved that the micro-helical robot driven by the conical rotating three-dimensional uni-form magnetic field can achieve high stability and no swing swimming in the low-frequency spiral propulsion state. This work may provide a reference for the future application of micro-helical robots in the fields of drug delivery, cell sorting, sensing and environmental repair in vivo. (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).