Supramolecular hydrogel actuators with reprogrammable magnetic orientation by locally mediated viscoelasticity and pinning force

Chuan Wei Zhang; Xing Peng Hao; Weifeng Zou; Zhixin Zhu; Jia Yu Hu; Li Xin Hou; Si Rui Xu; Zhen Luo; Yichen Yan; Andrea Sarabia; Andrea Litwak; Shili Xu; Zhi Jian Wang; Ximin He; Qiang Zheng; Zi Liang Wu

doi:10.1126/sciadv.adw0500

Supramolecular hydrogel actuators with reprogrammable magnetic orientation by locally mediated viscoelasticity and pinning force

Sci Adv. 2025 Jun 27;11(26):eadw0500. doi: 10.1126/sciadv.adw0500. Epub 2025 Jun 27.

Authors

Chuan Wei Zhang^{1

2}, Xing Peng Hao¹, Weifeng Zou³, Zhixin Zhu¹, Jia Yu Hu¹, Li Xin Hou¹, Si Rui Xu¹, Zhen Luo², Yichen Yan², Andrea Sarabia^{4

5}, Andrea Litwak^{4

5}, Shili Xu^{4

5

6}, Zhi Jian Wang⁷, Ximin He², Qiang Zheng¹, Zi Liang Wu¹

Affiliations

¹ Ministry of Education Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310058, China.
² Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
³ State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310058, China.
⁴ Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA.
⁵ Crump Institute for Molecular Imaging, University of California, Los Angeles, Los Angeles, CA 90095, USA.
⁶ Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA.
⁷ Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo 001-0021, Japan.

Abstract

Magnetic soft actuators with reprogrammable deformations have gained substantial attention due to their adaptability for various applications. However, achieving precise and local reorientation of magnetic particles remains challenging. Here, we present a strategy to locally tailor the viscoelasticity of magnetic supramolecular hydrogels, facilitate reorientation of the embedded magnetic particles, and enable reprogrammable magnetoactuated deformation and locomotion of the composite gels. The magnetic hydrogels are facilely prepared by mixing neodymium-iron-boron particles with an aqueous poly(acrylic acid-co-acrylamide) solution, which spontaneously forms supramolecular network with carboxylic-ferric ion coordinates as physical cross-links. This network enables dynamic control of viscoelasticity by localized laser heating, which reduces the pinning force of gel matrix and allows for reorientation of magnetic particles under a modest magnetic field. We demonstrate that the same hydrogel sheet can be reprogrammed to exhibit various complex deformations and locomotion. This versatile approach to developing magnetic hydrogels with adaptive responses offers exciting potential for soft robotics and biomedical devices.