{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T20:52:21Z","timestamp":1765486341934,"version":"build-2065373602"},"reference-count":25,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2019,10,15]],"date-time":"2019-10-15T00:00:00Z","timestamp":1571097600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Robotics"],"abstract":"<jats:p>One major challenge for microrobots is to penetrate and effectively move through viscoelastic biological tissues. Most existing microrobots can only propel in viscous liquids. Recent advances demonstrate that sub-micron robots can actively penetrate nanoporous biological tissue, such as the vitreous of the eye. However, it is still difficult to propel a micron-sized device through dense biological tissue. Here, we report that a special twisted helical shape together with a high aspect ratio in cross-section permit a microrobot with a diameter of hundreds-of-micrometers to move through mouse liver tissue. The helical microrobot is driven by a rotating magnetic field and localized by ultrasound imaging inside the tissue. The twisted ribbon is made of molybdenum and a sharp tip is chemically etched to generate a higher pressure at the edge of the propeller to break the biopolymeric network of the dense tissue.<\/jats:p>","DOI":"10.3390\/robotics8040087","type":"journal-article","created":{"date-parts":[[2019,10,16]],"date-time":"2019-10-16T03:32:54Z","timestamp":1571196774000},"page":"87","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["A Helical Microrobot with an Optimized Propeller-Shape for Propulsion in Viscoelastic Biological Media"],"prefix":"10.3390","volume":"8","author":[{"given":"Dandan","family":"Li","sequence":"first","affiliation":[{"name":"Cyber Valley Research Group, Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany"},{"name":"Micro, Nano, and Molecular Systems Group, Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany"}]},{"given":"Moonkwang","family":"Jeong","sequence":"additional","affiliation":[{"name":"Micro, Nano, and Molecular Systems Group, Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany"}]},{"given":"Eran","family":"Oren","sequence":"additional","affiliation":[{"name":"Bionaut Labs Ltd., Los Angeles, CA 90034, USA"}]},{"given":"Tingting","family":"Yu","sequence":"additional","affiliation":[{"name":"Cyber Valley Research Group, Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany"},{"name":"Micro, Nano, and Molecular Systems Group, Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0932-5605","authenticated-orcid":false,"given":"Tian","family":"Qiu","sequence":"additional","affiliation":[{"name":"Cyber Valley Research Group, Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany"},{"name":"Micro, Nano, and Molecular Systems Group, Max Planck Institute for Intelligent Systems, Heisenbergstrasse 3, 70569 Stuttgart, Germany"}]}],"member":"1968","published-online":{"date-parts":[[2019,10,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"eaam6431","DOI":"10.1126\/scirobotics.aam6431","article-title":"Micro\/nanorobots for biomedicine: Delivery, surgery, sensing, and detoxification","volume":"2","author":"Li","year":"2017","journal-title":"Sci. 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