Magnetically Powered Biodegradable Microswimmers.

Ho Cheung Michael Sun,Tanyong Wei,Dong Sun,Pan Liao,Li Zhang

doi:10.3390/mi11040404

Ho Cheung Michael Sun, Tanyong Wei + Show 3 more

Open Access

https://doi.org/10.3390/mi11040404

Copy DOI

Abstract

The propulsive efficiency and biodegradability of wireless microrobots play a significant role in facilitating promising biomedical applications. Mimicking biological matters is a promising way to improve the performance of microrobots. Among diverse locomotion strategies, undulatory propulsion shows remarkable efficiency and agility. This work proposes a novel magnetically powered and hydrogel-based biodegradable microswimmer. The microswimmer is fabricated integrally by 3D laser lithography based on two-photon polymerization from a biodegradable material and has a total length of 200 μm and a diameter of 8 μm. The designed microswimmer incorporates a novel design utilizing four rigid segments, each of which is connected to the succeeding segment by spring to achieve undulation, improving structural integrity as well as simplifying the fabrication process. Under an external oscillating magnetic field, the microswimmer with multiple rigid segments connected by flexible spring can achieve undulatory locomotion and move forward along with the directions guided by the external magnetic field in the low Reynolds number (Re) regime. In addition, experiments demonstrated that the microswimmer can be degraded successfully, which allows it to be safely applied in real-time in vivo environments. This design has great potential in future in vivo applications such as precision medicine, drug delivery, and diagnosis.

Highlights

Untethered mobile microrobots have demonstrated great potential in numerous microscale biomedical applications, such as minimally invasive therapy, drug and cell delivery, microsurgery, and in vivo sensing [1,2,3,4,5,6,7,8,9]
According to Purcell’s scallop theorem [10], in fluid environments with low Reynolds number (Re), viscous forces dominate compared to inertial forces
Microswimmers are a new form of cutting-edge technology that is designed to move in solutions and has the potential to provide a wide range of applications in medicine

Summary

Introduction

Untethered mobile microrobots have demonstrated great potential in numerous microscale biomedical applications, such as minimally invasive therapy, drug and cell delivery, microsurgery, and in vivo sensing [1,2,3,4,5,6,7,8,9]. Most of these undulating microswimmers are fabricated from multiple materials, including soft components, to generate undulatory locomotion, complicating the manufacturing process of the microrobots [25,26,33].

Results

Conclusion