A PolyU research team including Dr HE Yi, a postdoctoral fellow, together with Mr LUO Guojie (first author) and Mr ZHANG Wanglinhan, PhD students from PolyU’s Department of Mechanical Engineering, under the supervision of Prof. SU Zhongqing (corresponding author), Head and Chair Professor of Intelligent Structures and Systems from the same department, secured the Second Prize for Outstanding Report at the 7th International Symposium on Laser Ultrasonics and Advanced Sensing (LU2024) held in China in October. The team presented a paper titled “Photoacoustics-driven annular tweezers for acoustofluidic manipulation of particles" at the symposium.

The research pertains to developing a photoacoustics-driven annular tweezer for manipulating tiny particles or cells in micro/nanofluidics research, an intelligent manufacturing technique that brings significant applications in cell biology, clinical research, and biomedical engineering. The photoacoustics-driven annular tweezer developed in this research enables accurate, noncontact manipulation of particles or cells. Both theoretical modelling and in situ experiments have proven the effectiveness of this approach in the accurate micromanipulation of individual particles with a diameter of tens of microns in a fully noncontact manner (Figure 1).

Figure 1. Experimental Results

(a) Manipulation of a single silicon particle (~50 μm) The figure demonstrates the use of annular photoacoustic tweezers to selectively manipulate silica microspheres with a diameter of approximately 50 micrometres. The selected particles are gathered at the centre of the circle, while the unselected ones remain outside the laser ring.

(b)(c) Manipulation of a group of hydrogel droplets (~10 μm) The figures illustrate how annular photoacoustic tweezers selectively manipulate a group of hydrogel microspheres with a diameter of approximately 10 micrometres, gathering them at the centre of the circle.

LU2024, organised by the Nanjing University of Science & Technology, is dedicated to the latest scientific results, methodological and technological advancements, and applications of laser ultrasound, optoacoustics, phononics and light-matter-sound interactions. More than 65 papers and 23 posters were presented at the symposium.

Luo, G., He, Y., Zhang, W., & Su, Z. (2024). Photoacoustics-driven annular tweezers for acoustofluidic manipulation of particles. In Proceedings of the 7th International Symposium on Laser Ultrasonics & Advanced Sensing. 21-25 October 2024, Nanjing, China.