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Yu et al. Soft Sci. 2026, 6, 19 Page 3 of 24

Magnetic actuation has recently emerged as a promising alternative to address these challenges [28-30] .
Magnetically responsive soft materials-formed by embedding magnetic particles in an elastomeric matrix
and actuating them with an external field-enable wireless, non-contact deformation of soft structures . Kim
[31]
and Zhao have noted that magnetic soft composites combine substantial deformability with remote, accurate
control by applied magnetic fields . Ebrahimi et al. further analyzed actuation strategies, showing that
[32]
rotating fields enable continuous motion control, while gradient fields produce large-amplitude
displacements and grasping actions . Because magnetic interactions propagate effectively instantaneously,
[33]
magnetic soft robots offer the potential for millisecond-scale response times .
[34]

Although magnetic actuation has yielded notable advances in targeted drug delivery and micro/nanoscale
manipulation [35,36] , its application to underwater, high-load, adaptive grasping remains nascent. Existing
research, such as the magnetically driven origami gripper developed by Kim et al. , has shown good variable
[37]
stiffness characteristics, but its complex origami structure is prone to fatigue failure underwater; Li et al.
reported a porous magnetically driven flexible gripper, which increases the friction force during gripping
through the porous structure on the gripper surface, and realizes easy gripping of diverse targets . Recent
[38]
contributions include an octopus-inspired magnetic soft gripper capable of crawling and swimming ,
[39]
comprehensive reviews emphasizing magnetic actuation for adhesion and grasping , and cable-free
[40]
magnetic soft actuators that enhance operational autonomy . Programmable internal magnetization
[41]
schemes have permitted complex bending and twisting behaviors in small-scale devices [42,43] . Despite these
advances, most magnetic grippers reported to date have focused on regular objects; studies addressing fragile,
slippery or highly irregular underwater targets are comparatively scarce. Thus, designing a magnetic soft
gripper that combines rapid response, high reliability, and robust environmental adaptability for diverse
underwater targets remains a significant challenge. Motivated by this gap, we developed a bioinspired,
multi-finger magnetically driven soft gripper (MSG) featuring cilium-like microneedle surfaces, specifically
targeted at underwater resource acquisition tasks.

In addition to the above studies, this work introduces several new strategies and directions for MSG research.
Quantitative materials-actuation trade-off methodology. By systematically comparing Ecoflex0020/NdFeB
composites with different magnetic-filler mass fractions (e.g., 50 wt% vs. 60 wt%) in terms of Young’s
modulus, surface remanence, and key gripper performance metrics (response time, normalized
surface-roughness index, grasping success rate, etc.), we established quantitative relationships between
material composition and both the dynamic and static performance of the gripper. Using these quantified
relations, we performed a comprehensive assessment of grasping efficiency and non-destructiveness across
compositions, yielding practical design guidelines for selecting a magnetic-powder mass fraction that
balances “fast response” and “reduced biological damage risk”, and providing an empirical basis for
subsequent material and structural optimization of MSGs. Biomimetic microneedle surface treatment as a
novel solution to improve underwater contact friction. Friction tests comparing surfaces with and without
microneedles showed that cilia-like biomimetic microneedles significantly increase interfacial friction and
anti-slip capability. From an engineering perspective, the results validate that a microneedle surface can
enhance grasp stability for smooth or slippery targets, demonstrating broad potential for underwater robotic
applications . Decoupled analysis framework for deep-sea environmental effects. To increase the relevance
[44]
of this research to deep-sea deployment, we developed a framework that isolates the effects of hydrostatic
pressure and low temperature, and we validated MSG performance via hydrostatic high-pressure and
low-temperature grasping tests. The experimental results indicate that under extreme single-factor
conditions (high pressure or low temperature), the gripper’s structural integrity and key functional metrics
does not exhibit significant degradation, providing preliminary technical evidence to support future

engineering deployment under more complex combined high-pressure/low-temperature conditions.