Biomedical Microdevices

, 20:103 | Cite as

Preliminary study on alginate/NIPAM hydrogel-based soft microrobot for controlled drug delivery using electromagnetic actuation and near-infrared stimulus

  • Hyoryong Lee
  • Hyunchul Choi
  • Mikyoung Lee
  • Sukho ParkEmail author


Currently, microrobots are receiving attention because of their small size and motility, which can be applied to minimal invasive therapy. Additionally, various microrobots using hydrogel with the characteristics of biocompatibility and biodegradability are also being developed. Among them, microrobots that swell and deswell in response to temperature changes caused by external near infrared (NIR) stimuli, focused ultrasound, and an alternating magnetic field, have been receiving a great amount of interest as drug carriers for therapeutic cell delivery. In this study, we propose a spring type medical microrobot that can be manipulated by an electromagnetic actuation (EMA) system and respond to an external stimulus (NIR). Additionally, we verified its feasibility with regard to targeting and drug delivery. There exist various methods of fabricating a spring type microrobot. In this study, we adopted a simple method that entails using a perfluoroalkoxy (PFA) microtube and a syringe pump. Moreover, we also used a hydrogel mixture composed of natural alginate, N-Isopropylacrylamide (NIPAM) for temperature responsiveness, and magnetic nanoparticles (MNPs) for electromagnetic control. Then, we fabricated a spring type alginate/NIPAM hydrogel-based soft microrobot. Additionally, we encapsulated doxorubicin (DOX) for tumor therapy in the microrobot. To verify the feasibility of the proposed spring type hydrogel-based soft microrobot’s targeting and drug delivery, we developed an EMA and NIR integrated system. Finally, we observed the swelling and deswelling of the soft microrobot under NIR stimulation and verified the EMA controlled targeting. Moreover, we implemented a control function to release the encapsulated anticancer drug (DOX) through the swelling and deswelling of the soft microrobot by NIR, and evaluated the feasibility of cancer cell therapy by controlling the release of the drug from the soft microrobot.


Hydrogel-based microrobot Electromagnetic actuation Near-infrared stimulus Controlled drug releasing Magnetic nanoparticles Temperature responsive 



This work was supported by the DGIST R&D Program of the Ministry of Science and ICT (18-BD-0401) and by the Industrial Technology Innovation Program [10060059, Externally Actuatable Nanorobot System for Precise Targeting and Controlled Releasing of Drugs] of the Ministry of Trade, Industry and Energy (Korea).

Supplementary material

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ESM 1 (PDF 184 kb)
10544_2018_344_MOESM2_ESM.pdf (186 kb)
ESM 2 (PDF 185 kb)


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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Robotics EngineeringDaegu Gyeongbuk Institute of Science and Technology (DGIST)DaeguRepublic of Korea

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