A new study including Cluster Postdoctoral Researcher Fan Nan, Doctoral Researcher Josephine Spiegelberg and Principal Investigators Martin Wegener and Moritz Kreysing presents a new, light-driven method for contact-free 3D rotation and spinning of microscopic objects in highly viscous environments. The researchers generated tiny helical fluid flows capable of moving, trapping, rotating, and spinning a broad range of structures, including spherical particles, 3D-printed microstructures, and biological cells, by rapidly scanning a mildly heating laser spot within a two-dimensional plane. The team also showed that carefully designed laser scanning patterns enable precise control of these microscopic flow fields. The highly viscous medium suppresses Brownian motion and stabilizes particle movement. When combined with volumetric microscopy, this approach enables stepwise sample rotation and multi-angle imaging. This opens new opportunities for advanced microscopy, microrobotics, and light-controlled micromanipulation.
© Nan et al., Light: Science & Applications (2026), CC BY 4.0