New 3D Optical Fibre Gripper Enables High-Precision Micromanipulation

Researchers have developed a novel 3D optical fibre gripper (OFG) that bridges the gap between the delicate, low-force capabilities of optical tweezers and the bulkier, high-force nature of mechanical micro-tools. Measuring just 38 by 38 by 61 micrometres, this device utilizes a two-step, two-photon polymerization process to integrate rigid photoresist microclaws with a thermoresponsive hydrogel muscle doped with silver nanoparticles. This unique architecture allows for precise, reversible, and tunable gripping at a scale previously difficult to achieve.

The OFG demonstrates a force-to-mass ratio approximately 100 to 1,000 times greater than existing fibre-integrated tweezers. Its ability to manipulate opaque, irregular objects and diverse single-cell types makes it a versatile tool for both biological research and micro-engineering. By leveraging photothermal actuation, the gripper can operate effectively within confined spaces, such as narrow channels under 300 micrometres, where traditional mechanical tools would be too large and optical tweezers would lack the necessary force.

This innovation holds significant implications for the future of micro-assembly and biomedical sampling. By enabling the construction of complex micro-devices—such as miniature bearings, shafts, and gearboxes—and facilitating delicate single-cell manipulation, the OFG provides a robust platform for high-performance micromanipulation. As a compact, fibre-tip solution, it offers a scalable path toward more sophisticated, automated micro-robotic systems capable of performing intricate tasks in environments that were once considered inaccessible.