Multidimensional Motion and Manipulation of Optothermal Bubble Microrobots in Dimethyl Silicone Oil via Remote Laser Control.

The precise control of droplets and bubbles is critical for advancing microfluidics, micro/nano robotics, and lab-on-a-chip technologies, enabling a broad spectrum of applications. However, despite preliminary demonstrations of 3D bubble motion, current strategies are harshly limited by interface dependence. The goal of achieving multidimensional control of bubbles for complex micromanipulation and assembly tasks remains a significant challenge. Here, we propose a novel strategy for 3D micromanipulation by leveraging laser-generated optothermal bubbles within a dimethyl silicone oil medium. Unlike conventional systems where bubble-based microrobots are confined to 2D motion at solid-liquid interfaces, our approach enables complex multidimensional mobility. The optothermal bubble microrobots demonstrated various capabilities, including 2D remote attraction, simultaneous control of multiple bubbles, 3D ascent, and controlled reattachment. We successfully showcase its application in the precise manipulation and assembly of microstructures in 3D space. This 3D bubble microrobot functions as a versatile micromanipulation tool. It may overcome the fundamental limitations of previous bubble-driven systems and opens new avenues for sophisticated microrobotic operations.