Micro-rocket robot with all-optic actuating and tracking in blood

Dengfeng Li,Yuanyuan Yang,Chao Liu,Yajing Shen,Lidai Wang

doi:10.1038/s41377-020-0323-y

Abstract

Micro/nanorobots have long been expected to reach all parts of the human body through blood vessels for medical treatment or surgery. However, in the current stage, it is still challenging to drive a microrobot in viscous media at high speed and difficult to observe the shape and position of a single microrobot once it enters the bloodstream. Here, we propose a new micro-rocket robot and an all-optic driving and imaging system that can actuate and track it in blood with microscale resolution. To achieve a high driving force, we engineer the microrobot to have a rocket-like triple-tube structure. Owing to the interface design, the 3D-printed micro-rocket can reach a moving speed of 2.8 mm/s (62 body lengths per second) under near-infrared light actuation in a blood-mimicking viscous glycerol solution. We also show that the micro-rocket robot is successfully tracked at a 3.2-µm resolution with an optical-resolution photoacoustic microscope in blood. This work paves the way for microrobot design, actuation, and tracking in the blood environment, which may broaden the scope of microrobotic applications in the biomedical field.

Highlights

The development of autonomous artificial micro/nanorobots has attracted considerable attention due to their potential in various biomedical applications, such as in vivo treatment or surgery[1]
We develop an optical-resolution photoacoustic microscopy (OR-PAM) system to track a single microrobot in the bloodstream (Fig. 1)
Volumetric images are obtained by raster scanning of the OR-PAM probe

Summary

Introduction

The development of autonomous artificial micro/nanorobots has attracted considerable attention due to their potential in various biomedical applications, such as in vivo treatment or surgery[1]. Scientists have desired that microrobots be able to reach all parts of the human body through blood vessels to assess or treat diseases in different organs[2]. To assist robots in entering other organs, blood vessels are the best channel, as blood is circulated throughout the body. The development of microrobots that can work in the blood faces many challenges, including the achievement of effective actuation and precise observation, which become more serious for a robot with a size of less than 100 μm. Different from the open environment in a lab, a microrobot experiences harsh situations in blood, which is a viscous and fast-flowing environment that can be difficult to swim through. Magnetic field actuation often shows good biological compatibility due to its noninvasive peculiarity and good controllability in viscous liquids[8,9]

Methods

Results

Conclusion