Optically Driven Gear-Based Mechanical Microtransducer for a Lab-on-a-Chip

Lee, Yi-Hsiung; Liu, Yi-Jui; Tzou, Ching-Fu; Bouriau, Michel; Baldeck, Patrice L.; Lin, Chih-Lang
In this study, we propose an optically driven gear-based microtransducer composed of a mechanical arm, a sphere, and two gears, which are fabricated by two-photon polymerization technique. Optical tweezers is employed to grasp the sphere as a force exerted point to manipulate the mechanical arm. The two gears with different diameters to form a required gear ratio are meshed for the tranducing demonstration. Thanks to the classic lever function, the mechanical arm can multiply the optical tweezers force as the request of tranducing performance. The experimental result indicates that the transducer enables precise applied forces and the directions of the microtransducer by optical tweezers at micron scale. The ratio of rotational angles has good agreement with the gear ratio as the classic gear function. Such gear-based optically driven mechanical transducer provides a possibility for driving micron-sized complex mechanisms, which is expected to perform as a mechanical operator in micro-channels for the applications of the “Lab-on-a-chip.“
DOI

Design and Two-Photon Polymerization of Complex Functional Micro-Objects for Lab-on-a-Chip: Rotating Micro-Valves

Chung, Tien-Tung; Tseng, Chang-Li; Hung, Chia-Ping; Lin, Chih-Lang; Baldeck, Patrice L.
Two-Photon Polymerization is a powerful technology that can be used to fabricate complex functional micro-objects in lab-on-a-chip platforms. It is a laser-based prototyping technique with full tri-dimensional capability and sub-micron resolution. We report on the development of a computer-assisted design and fabrication process based on Q-switched Nd:YAG microlasers and AutoCAD environment. Microlasers with sub-nanosecond pulses of visible light are efficient and low cost lasers for two-photon microfabrication. Polymerization is easily obtained with sub-milliwatt average powers (12 kHz repetition rate). The microfabrication software has been developed to design the micro-object models and to calculate their laser trajectories using AutoCAD. It is open platform for the design of 3D solids with full access to entities information, and an efficient slicing command that can cut solids from any orientation plane. As a typical example of complex functional micro-object, we report on the fabrication of laser-driven rotating micro-valves. The design parameters have been optimized to allow a free movement of the valve around its axis using the optical force of a laser tweezers.
DOI