Light-Controlled Microgripper Merges Precision with Force
Researchers have developed a 3D optical fiber gripper, measuring just 38x38x61 micrometers, that combines the precision of light-based manipulation with the gripping strength of mechanical devices.
A new miniature mechanical gripper, controlled by light signals transmitted through an optical fiber, has been developed by a team led by Dong Wu at Anhui University. This innovation aims to bridge the gap between the high precision of optical tweezers and the limited force they can exert, potentially simplifying microscale object manipulation and assembly.
Traditional optical tweezers use focused laser beams to trap and move microscopic objects with piconewton forces, making them suitable for delicate items like molecules and cells but ineffective for larger, irregular, or opaque objects. To overcome this limitation, Wu's team utilized two-photon polymerization, a 3D printing technique, to fabricate a 3D optical fiber gripper (OFG) on the tip of an optical fiber. The device, measuring only 38x38x61 micrometers, integrates a light-transmitting optical fiber, a silver nanoparticle-infused hydrogel acting as a muscle, and rigid polymer claws.
When near-infrared laser light travels through the fiber and hits the nanoparticles, it heats the hydrogel, causing it to contract and open the claws. The claws close when the light is removed. This system responds quickly, with reported actuation times of 77 milliseconds and the ability to open and close up to five times per second. The OFG can generate forces in the micronewton range, significantly exceeding the capabilities of previous fiber-based tweezers.
Experiments demonstrated the gripper's versatility in handling diverse objects, including alumina spheres, silicon carbide fragments, and even long copper wires. It successfully grasped, transported, and released individual human cancer cells without causing damage. Furthermore, the device was used to assemble miniature mechanical components with micrometer precision. Its small size also allows access to confined spaces, such as channels narrower than 300 micrometers and excised animal tissue, opening possibilities for applications in single-cell biology, minimally invasive surgery, and micro-machine construction.
This development is significant as it overcomes a key limitation of optical tweezers by integrating mechanical gripping capabilities with light-based control. The ability to generate micronewton forces at the microscale, combined with micrometer precision, is crucial for advanced microassembly and manipulation tasks. This could accelerate progress in fields requiring intricate construction of microscopic devices and manipulation of biological samples, potentially impacting areas like advanced manufacturing and biomedical engineering.
Edited by the news editor with AI from the original report — please refer to the original source.