A Chinese research team has made new progress in the field of micro-nano manipulation. A collaborative team from Anhui University and the University of Science and Technology of China has successfully developed three-dimensional fiber optic micro-tweezers integrated at the tip of an optical fiber, enabling high-precision, low-damage, and programmable three-dimensional manipulation of micrometer-scale targets. The related findings have been published in the international academic journal Nature.
This research addresses long-standing bottlenecks in existing micro-manipulation technologies. Traditional optical tweezers offer advantages such as non-contact operation and high precision, but their output force is weak, and they impose high requirements on target transparency and operating environment. While mechanical, pneumatic, or hydraulic micro-grippers can provide greater force, their system size and external drive structures are complex, making it difficult to access narrow spaces at the hundred-micrometer scale, such as microvessels and bile ducts.
The research team proposed a femtosecond laser composite manufacturing method for fiber-based integrated devices, constructing three-dimensional fiber optic micro-tweezers at the tip of a commercial optical fiber. This device integrates light transmission, photothermal conversion, soft material response, and rigid microstructure mechanical output at the tip of a single fiber, transforming the fiber from merely a channel for transmitting optical signals and energy into an integrated platform capable of performing microscale mechanical operations.
The working principle of the three-dimensional fiber optic micro-tweezers is analogous to a "miniature dexterous hand" at the cellular scale. External light is transmitted through the fiber to the tip microstructure, triggering material response and microstructure deformation, which is then converted into controllable opening and closing actions and mechanical output. By adjusting the input optical power, researchers can continuously control the opening and closing state and force magnitude of the micro-tweezers, achieving precise micro-manipulation through "light-driven force."
Experimental results show that the output force of this new micro-tweezers is over 100,000 times greater than that of traditional optical tweezers. It can not only precisely manipulate micrometer-scale targets but also perform complex microstructure assembly and microscale sampling in narrow spaces at the hundred-micrometer scale. The related paper also demonstrates the potential applications of this device in three-dimensional fine manipulation of single cells, assembly of micro-mechanical structures, and bionic sampling in confined environments.
Femtosecond laser micro-nano processing is a key enabler of this achievement. This technology can fabricate complex three-dimensional structures at the micrometer or even nanometer scale and, combined with multi-material composite design, form microsystems with driving, response, and mechanical output capabilities. For the extremely small space at the fiber tip, high-precision processing capability directly determines whether the device can achieve stable opening and closing, controllable gripping, and repeatable operation.
This achievement provides new technical pathways for fields such as life sciences, minimally invasive medicine, cell manipulation, and advanced manufacturing. In the future, if the three-dimensional fiber optic micro-tweezers can be further validated in terms of biocompatibility, stability, batch manufacturing, and clinical scenarios, they are expected to be applied in areas such as single-cell manipulation, microscale sampling, minimally invasive endoscopic tools, and complex microstructure assembly.
Subsequent research will focus on device reliability, operational safety, adaptability to different biological samples, and system integration level. The three-dimensional fiber optic micro-tweezers still require further validation before practical medical or industrial applications, but their high output force, miniaturization, and fiber integration characteristics in precise micrometer-scale manipulation have already provided a new design direction for micro-nano manipulation tools.