Miniature Photo-Driven Microbubble Capture Actuator Based on Optical Fiber Microcavity

Micronano capture systems capable of efficiently trapping target particles have been a focus in biomedical engineering, lab-on-a-chip devices, and targeted drug delivery. Here, we propose a miniature photodriven microbubble capture actuator based on an optical fiber microcavity. The actuator consists of an optical fiber microcavity and a graphene oxide/polydimethylsiloxane-gold nanobipyramids (GO/PDMS-AuNBPs) photothermal composite film. The composite film exhibits high photothermal conversion efficiency, enabling the actuator to generate a stable temperature gradient in a liquid environment. The resulting temperature gradient induces a surface tension gradient along the surface of the bubble, thereby driving the bubble toward the trapping actuator. Both theoretical analyses and experimental results confirm that the actuator successfully captures microbubbles with radii of 5 to 200 μm. Compared with conventional particle capture technologies, the proposed actuator offers several advantages, including low power consumption, a compact structural design, and high stability in liquid environments. The system provides a novel platform for biomedical applications such as live cell manipulation and microreactor construction.