Collective transport of particles and cells enabled by wavelength-division multiplexing in microcavity cascade optical tweezers

This study presents a microcavity cascade optical tweezer (MCOT) system incorporating wavelength-division multiplexing for collective transport of particles and cells in biomedical applications. The MCOT system traps and transports yeast cells (5 μm) and silica microspheres using 980 nm and 1550 nm lasers, with a maximum capacity of six particles. Under 980 nm laser illumination, capillary microflow force surpasses optical forces, stably trapping particles and cells in the microcavity. At 1550 nm, significant heat absorption excites thermophoretic forces, which, combined with optical forces, enhance particle transport. Experimental results closely match simulations, confirming the system's potential for efficient particle and cell transport, especially for drug and cell delivery applications.