Biomimetic two-stage micro@nanomotor with weak acid-triggered release of nanomotors

Liang Gui^{¹^,^§}, Jiameng Feng^{²^,^§}, Haodong Guo^², Xiaoyu Li^³, Junjie Zou^¹(), Xin Du^²

()

1Department of Vascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China

2Beijing Key Laboratory for Bioengineering and Sensing Technology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China

3National Engineering Research Center of green recycling for strategic metal resources, Key Laboratory of Green Process and Engineering, Institutional Center for Shared Technologies and Facilities, Institute of Process Engineering, Chinese Academic of Sciences, University of Chinese Academic of Sciences, Beijing 100190, China

^§ Liang Gui and Jiameng Feng contributed equally to this work.

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Inspired by the suckerfishes−shark motion behavior, we designed and prepared a kind of near infrared ray (NIR) light-propelled micro@nanomotor with weak acid-triggered release of H₂O₂ driven nanomotor.

Abstract

Bionic micro/nanomotor systems, which combine biomimetic design with the motion performance, have shown great potential in many fields. However, so far, it remains a challenge to design and fabricate biomimetic micro/nanomotors with high flexibility to perform complex tasks in complicated and changeable environments. In this work, inspired by the suckerfishes (guest)–shark (host) motion behavior, we designed and prepared a kind of intelligent two-stage micro@nanomotor with weak acid-triggered release of nanomotor. When the suckerfishes, who clinged to the surface of large fish or the bottom of boat and marched with them, reached bait-rich waters, they detached from the host to engage in foraging behavior. Inspired by the suckerfishes–shark system and the coordinated bond interaction, a large amount of Janus Au-Pt nanomotors with hydrogen peroxide (H₂O₂)-driven capacity, analogous to suckerfishes, were attached onto immovable yolk–shell structured polydopamine-mesoporous silica (PDA-MS) micromotor as the host to create two-stage PDA-MS@Au-Pt micro@nanomotor. PDA-MS@Au-Pt micro@nanomotor moved directionally by self-thermophoresis under the propulsion of near infrared ray (NIR) light with low power density. When the PDA-MS@Au-Pt entered into the weak acidic environment formed by a low concentration of H₂O₂, most small Au-Pt nanomotors were detached from the surface of PDA-MS due to the weak acidic sensitivity of the coordinated bond, and then performed self-diffusiophoresis in the environment containing a low concentration of H₂O₂ as a chemical fuel. This bionic intelligent system, which consists of a large-sized micromotor and lots of small-sized nanomotors, should provide a new insight for active two-stage cargo delivery.

Keywords

micro/nanomotor bionic design acid-triggered release H₂O₂ propulsion near infrared ray (NIR) light propulsion

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References

[1]

Chen, C. R.; Ding, S. C.; Wang, J. Materials consideration for the design, fabrication and operation of microscale robots. Nat. Rev. Mater. 2024, 9, 159–172.