Gear-based 3D-printed Micromachines Actuated by Optical Tweezers

TL;DR

This paper introduces a novel optomechanical micromachine fabricated via 3D printing, actuated by optical tweezers, enabling light-controlled gear systems with out-of-plane rotation for biomedical and lab-on-a-chip applications.

Contribution

It presents the first integration of 3D-printed gear trains with optical tweezer actuation, allowing precise, light-controlled micromachine operation at the microscale.

Findings

Successful fabrication of gear trains with two-photon polymerization

Demonstration of continuous rotation and motion transmission

Out-of-plane gear rotations enabled by design

Abstract

The miniaturization of mechanical mechanisms is crucial to enable the development of compact, high-performance micromachines. However, the downscaling actuation of conventional gears and micromotors has remained limited by the inherent challenges of implementing mechanical/electrical powering. Here, we present the design, fabrication, and characterization of an optomechanical, gear-driven micromachine realized through two-photon polymerization 3D printing. The actuation is achieved using optical tweezers. The device integrates a microgear transmission system with an optically actuated part, enabling light-controlled micromachines. When illuminated by a highly focused laser source, the first gear generates rotational torque within the gear assembly, converting optical energy into directional mechanical work that can be transmitted to the coupled gear. We demonstrate the fabrication of micromachines using two-photon polymerization (2PP) laser writing, enabling the fabrication of spur gear trains and bevel gears that can produce out-of-plane rotations, which is not achievable with traditional micromachining fabrication techniques. The micromachines are composed of a single gear or a train of two or three gears without any unwanted adhesion between the components, leading to functioning systems. Experimentally, the fabricated micromachines were actuated using optical tweezers, demonstrating continuous gear rotation, effective motion transmission in gear trains, out-of-plane rotations, and the ability to amplify velocity or torque. Optical-tweezer actuation broadens the potential applications of these micromachines, particularly in biomedical and lab-on-a-chip systems, where precise, minimally invasive control at the microscale is essential.