{
  "abstract": "The navigation and control of untethered magnetic robots (UMRs) within soft brain tissue critically depend on their ability to maintain synchronized rotation under applied rotational magnetic fields. The fundamental upper limit of this magnetic synchronization, known as the step‐out frequency, directly affects propulsion efficiency and control stability. This study presents an empirical model for predicting the step‐out frequency of UMRs operating in ex vivo brain tissue with viscoelastic properties representative of the in vivo environment. Using Buckingham Pi dimensional analysis, we derive a compact set of dimensionless groups that capture the effects of robot geometry and tissue viscoelasticity, with magnetic torque used as the scaling basis. Experimental validation with spiral‐type UMRs in gelatin‐based phantoms shows that the step‐out frequency decreases exponentially, from approximately 30 Hz in low‐stiffness media (complex shear modulus ∼400 Pa) to below 1 Hz in high‐stiffness media (complex shear modulus ∼1600 Pa). The found relationship allows for rapid estimation of robot performance limits using a single calibration point, enabling efficient evaluation of robot design and actuation parameters. The resulting framework supports the clinical translation of magnetic microrobots for precise therapeutic and surgical interventions in brain tissue.",
  "abstract_shown": true,
  "affiliations": [
    "RAM—Robotics and Mechatronics University of Twente Enschede The Netherlands",
    "Radboud University Medical Center Nijmegen The Netherlands",
    "Technical Medical Centre University of Twente Enschede The Netherlands",
    "Mesoscale Chemical Systems, MESA+ Institute University of Twente Enschede The Netherlands",
    "Department of Physics German University in Cairo New Cairo Egypt",
    "Department of Dentistry‐Regenerative Biomaterials Radboud University Medical Center Nijmegen The Netherlands",
    "LipoCoat B.V. Enschede The Netherlands",
    "Department of Molecules and Materials, Biointerface Chemistry Lab University of Twente Enschede The Netherlands",
    "Triticum Medical Ramat HaSharon Israel",
    "The Hebrew University of Jerusalem Rehovot Israel",
    "Department of Surgery, Division of Vascular and Transplant Surgery Radboud University Medical Center Nijmegen Nijmegen The Netherlands"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 20,
  "authors": [
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Leendert‐Jan W. Ligtenberg",
      "orcid": "0009-0001-1960-5283"
    },
    {
      "affs": [
        0
      ],
      "name": "Thijs J. van der Burg",
      "orcid": "0009-0001-5737-9096"
    },
    {
      "affs": [
        0
      ],
      "name": "Stijn Y. Kolkman",
      "orcid": "0009-0008-6717-6277"
    },
    {
      "affs": [
        2,
        3
      ],
      "name": "Santiago Saavedra Castano",
      "orcid": "0000-0002-8790-2175"
    },
    {
      "affs": [
        2,
        3
      ],
      "name": "David Fernandez Rivas",
      "orcid": "0000-0003-4329-3248"
    },
    {
      "affs": [
        4
      ],
      "name": "Anke Klingner",
      "orcid": "0000-0002-2426-433X"
    },
    {
      "affs": [
        1
      ],
      "name": "Roger M. L. M. Lomme",
      "orcid": "0000-0002-4856-9234"
    },
    {
      "affs": [
        1,
        5
      ],
      "name": "Lucas S. Joziasse",
      "orcid": "0009-0007-4033-6667"
    },
    {
      "affs": [
        6,
        7
      ],
      "name": "Dorothee Wasserberg",
      "orcid": "0000-0002-1493-2971"
    },
    {
      "affs": [
        2
      ],
      "name": "H. Remco Liefers",
      "orcid": "0009-0006-2149-3731"
    },
    {
      "affs": [
        8
      ],
      "name": "Doron Ben Ami"
    },
    {
      "affs": [
        8
      ],
      "name": "Udi Sadeh",
      "orcid": "0000-0003-0549-2684"
    },
    {
      "affs": [
        8,
        9
      ],
      "name": "Oded Shoseyov",
      "orcid": "0000-0003-3340-9921"
    },
    {
      "affs": [
        0,
        2
      ],
      "name": "Giulio Dagnino",
      "orcid": "0000-0002-1613-1051"
    },
    {
      "affs": [
        2,
        6,
        7
      ],
      "name": "Pascal Jonkheijm",
      "orcid": "0000-0001-6271-0049"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Jurgen J. Fütterer",
      "orcid": "0000-0001-6800-2879"
    },
    {
      "affs": [
        0
      ],
      "name": "Stefano Stramigioli",
      "orcid": "0000-0001-8212-7387"
    },
    {
      "affs": [
        1
      ],
      "name": "J. Frank W. Nijsen",
      "orcid": "0000-0001-7625-2253"
    },
    {
      "affs": [
        1,
        10
      ],
      "name": "Michiel C. Warlé",
      "orcid": "0000-0002-1151-4571"
    },
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Islam S. M. Khalil",
      "orcid": "0000-0003-0617-088X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/a1ctmrnsrf2vz.bib",
  "cited_by": 1,
  "doi": "10.1002/advs.77011",
  "fulltext_url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC13474191/",
  "id": "a1ctmrnsrf2vz",
  "issns": [
    "2198-3844"
  ],
  "landing_url": "https://doi.org/10.1002/advs.77011",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Research Article"
    ],
    [
      "openalex",
      "3104|Micro and Nano Robotics"
    ]
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  "openalex": "W7203445536",
  "pdf_url": null,
  "pmcid": "PMC13474191",
  "pmid": "42598752",
  "published": "2026-08-14",
  "publisher": "Wiley",
  "ris": "https://research.draconitic.com/paper/a1ctmrnsrf2vz.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T12:23:13Z",
      "native_id": "PMC13474191",
      "source": "pmc",
      "url": "https://doi.org/10.1002/advs.77011"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "openalex:3104|Micro and Nano Robotics",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Performance Estimation and Ex Vivo Validation of Untethered Magnetic Robots in Soft Tissue",
  "title_text": "Performance Estimation and Ex Vivo Validation of Untethered Magnetic Robots in Soft Tissue",
  "type": "peer-reviewed",
  "updated_at": "2026-11-07T12:20:32Z",
  "url": "https://research.draconitic.com/paper/a1ctmrnsrf2vz",
  "venue": "Advanced Science",
  "versions": []
}