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Fabrication methods of magnetic helical swimmers. (a) A method based on the self-rolling of a three-layer strained film with a nickel magnetic head [63]. Copyright 2009, American Chemical Society. (b) Glancing angle deposition (GLAD) method [120]. Copyright 2009, American Chemical Society. (c) Three-dimensional direct laser lithography (DLW) [117]. John Wiley & Sons (Hoboken, NJ, USA). Copyright © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany.
