AccScience Publishing / IJB / Online First / DOI: 10.36922/IJB025460475
RESEARCH ARTICLE
Early Access

3D-printed biodegradable hydrogel microrobots for controlled therapeutic delivery

Pan Liao1,2,3* Junyang Li2 Shuxun Chen2 Yi Hou4* Guangda Zhu3* Dong Sun2
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1 Laoshan Laboratory, Qingdao 266237, China
2 Department of Biomedical Engineering, City University of Hong Kong, Hong Kong 999077, China
3 Research Center for Materials, Architectures, and Integration of Nanomembranes, TU Chemnitz, Chemnitz 09126, Germany
4 Centre for Translational Bone, Joint and Soft Tissue Research, TU Dresden, Dresden 01307, Germany
Received: 14 November 2025 | Accepted: 2 December 2025 | Published online: 2 December 2025
© 2025 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
Abstract

Precise delivery of therapeutic agents to targeted sites within the body is a significant challenge, especially in complex and confined physiological environments. Magnetically actuated microrobots offer a promising solution by enabling remote, controllable, and minimally invasive navigation; however, most existing microrobotic systems are fabricated from nondegradable materials and lack controlled drug release capability, which significantly limits their clinical translation. Here, we report 3D-printed biodegradable magnetic microrobots based on gelatin methacryloyl (GelMA) hydrogel capable of controlled therapeutic delivery. Using high-resolution direct laser writing, dual-layer GelMA microrobots with distinct crosslinking degrees were fabricated, enabling tunable degradation and controlled release of encapsulated drugs. The low-crosslinked outer shell functions as a protective barrier that prevents premature drug diffusion, while the highly crosslinked inner core enables sustained drug release during enzymatic degradation. The microrobots demonstrate excellent biocompatibility and controllable degradation in cellular environments. In addition, the integration of a biocompatible magnetic skeleton within the GelMA body enhances mechanical stability and enables precise magnetic actuation. This study presents a versatile strategy for developing biodegradable, magnetically actuated microrobots with controlled therapeutic release, offering strong potential for targeted drug delivery, tissue regeneration, and minimally invasive biomedical applications.

Keywords
Direct laser writing
Biodegradable microrobots
Magnetic actuation
Controlled drug release
Targeted therapy
Funding
This work was supported by the Shandong Provincial Natural Science Foundation (Grant No. ZR2025QC1530) and the Taishan Scholars Program.
Conflict of interest
The authors declare they have no competing interests.
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International Journal of Bioprinting, Electronic ISSN: 2424-8002 Print ISSN: 2424-7723, Published by AccScience Publishing