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Page 8 of 26 Chen et al. Soft Sci. 2026, 6, 3

intestinal wall, bladder, and vasculature. The resulting mechanical compliance allows the robots to contact
tissue surfaces without damage, enabling controlled navigation and targeted delivery across diverse
anatomical environments. To traverse complex luminal environments, such as tortuous blood vessels or
narrow esophageal passages, magnetic soft robots can be designed with specialized mechanical structures or
customized magnetization patterns, allowing smooth navigation without causing tissue injury. A
magnetically steered continuum robot employs helical surface protrusions and an articulating magnetic tip
to translate rotational input into forward motion, thereby reducing mechanical stress on vessel walls [160] .
Similarly, various magnetization patterns in multiple sections of the magnetic skin (M-skin) catheter enable
controlled deformation, allowing adaptation to sharp corners and narrow passages in the throat, esophagus,
and urethra . This design allows rapid directional steering and reduces the risk of extrusion against delicate
[72]
tissues. Beyond initial mechanical compliance, degradation dynamics must be finely tuned to maintain
functional performance throughout the intended therapeutic window [161,162] . Premature degradation may
impair robotic functionality, whereas delayed resorption prolongs foreign body presence, increasing the
likelihood of immune activation or infection.

Surface topography further modulates tissue-material interactions. Soft and conformal interfaces are
associated with attenuated immune activation, potentially reducing inflammatory responses caused by
stiffness mismatches at the tissue-robot interface. In contrast, rough or irregular surfaces are more likely to
trigger foreign body responses, leading to increased macrophage adhesion, fibrosis, and impaired device
performance . To overcome these challenges, surface engineering strategies such as hydrogel coatings have
[12]
been employed to minimize interfacial irritation while preserving actuation capabilities [98,163] .

Infection and inflammation
In clinical settings, device-associated infections account for a substantial proportion of healthcare-related
complications and may result in severe complications such as septic shock and mortality [164] . To minimize
these risks, both the fabrication of magnetic soft robots and their interventional deployment must adhere to
stringent aseptic protocols. In particular, the motion or prolonged implantation of magnetic soft robotic
systems in mucosal environments can compromise epithelial integrity, leading to microbial translocation and
localized immune responses [165] . Moreover, inflammation may be further exacerbated by surface-induced
friction and microtrauma at the robot-tissue interface. To mitigate these responses, biocompatible hydrogel-
based coatings, such as polydimethylacrylamide, have been engineered to reduce interfacial shear stress and
friction . Experimental results have shown a 10-fold decrease in the friction coefficient as a result of the
[76]
lubricious hydrogel skin, thereby improving safety and minimizing vessel-wall irritation. For clinical
applications involving direct contact with circulating blood, such as magnetically guided intravascular soft
robots, rigorous evaluation of hemocompatibility is essential. The blood environment is highly dynamic and
protein-rich, which promotes protein adsorption on material surfaces and increases the likelihood of
thrombus formation. This risk can be further exacerbated in venous circulation, where slower flow rates and
longer residence times may accelerate thrombus growth compared with arteries. Careful material assessment
is therefore essential to minimize hemolysis, thrombosis, and other adverse responses during therapeutic
use [160,166] . Achieving immunological compatibility and mitigating the foreign-body response are therefore
essential for ensuring long-term safety, functional reliability, and clinical feasibility .
[167]

ORGAN-SPECIFIC MATERIALS AND STRUCTURAL DESIGNS
Recent advances in biomedical applications of magnetic soft medical robots are reviewed in this section, with
focused discussions on targeted drug delivery, endoluminal diagnostics, microsurgical assistance, and
localized therapies. We highlight representative design strategies and performance in physiological
environments, demonstrating their roles in advancing precision medicine and minimally invasive
intervention [Table 2].