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Lin et al. Soft Sci 2023;3:14 https://dx.doi.org/10.20517/ss.2023.05 Page 19 of 25

(MEG) and other electrophysiological signals of the human body outside of hospital/laboratory settings in a
wireless, continuous manner, simply by measuring the resistance change of the material. For soft robotics,
the synthesis and fabrication of high-performance and biocompatible magnetic materials can open avenues
for many biomedical applications. Most magnetic materials are either biologically toxic (e.g., NdFeB, Ni and
Co) [183-186] or vulnerable to biofluids (e.g., Fe and Fe O ) [187,188] . Although some magnetic materials, such as
2
3
[189]
FePt, show good biocompatibility and stability , their remanence and coercivity demand further
improvement to compete with state-of-the-art hard-magnetic materials.
The other opportunity is to invent new manufacturing schemes for magnetic nanomaterials. On the one
hand, applications in soft electronics, in many cases, rely on heterogeneous integrations of multiple
functional components. The requirements on high temperature and/or large magnetic field for GMR/AMR/
TMR materials, and the incompatibility with lithographic techniques for some silicone elastomers impede
the integration of these materials with other functional components. Developing transfer printing schemes
or other similar processes to assemble magnetic soft electronics and other sensors, stimulators, radios,
circuits, etc. into the same system in a parallel and large-scale fashion represents a means to mitigate this
issue. On the other hand, micro/nano manipulation and minimally invasive surgery represent promising
applications of soft robotics, in which case the dimensions of the robots need to be in submillimeter or
micro scale. Manufacturing approaches that can build microscale 3D robots with multi-material integration
are, therefore, essential for practical applications. Some recently developed procedures, such as compressive
buckling and stress-induced bending [158,190,191] , can play important roles in this area after proper adaptations.

In summary, soft electronics and robotics based on magnetic nanomaterials are of interest for applications
such as human-machine interface, multimodal sensing, and biomedicine. These emerging soft magnetic
systems add to a growing body of capabilities in sensing and actuation. Further developments in materials
and manufacturing approaches create more opportunities in areas ranging from environmental sensing and
minimally invasive surgeries to continuous, wireless monitoring and mapping of health status. These
magnetic soft electronics and robotics have the potential to integrate with existing systems to broaden their
functions and promote practical applications. These collective advances hold promise to revolutionize a
wide range of fields, including biomedicine, electronics, and fundamental research in physics and materials
science.

DECLARATIONS
Authors’ contributions
Initiated the idea: Lin X, Han M
Did the literature review: Lin X
Outlined the manuscript structure: Lin X, Han M
Wrote the manuscript draft: Lin X
Designed and formatted the figures: Lin X
Reviewed and revised the manuscript: Lin X, Han M
All authors have read the manuscript and approved the final version.

Availability of data and materials
Not applicable.

Financial support and sponsorship
This work was supported by the National Natural Science Foundation of China (No. 62104009), and the
Emerging Engineering Interdisciplinary Project, Peking University, the Fundamental Research Funds for
the Central Universities.