Non-Invasive Interception of Circulating Leukocyte In Vivo by Optical Tweezer Array

The ability to non-invasively manipulate and isolate specific cell populations in vivo is critical for advancing real-time diagnostics, precision medicine, and immunological research. Here, we present a novel and broadly applicable optical trapping system based on a custom-designed 2×3 optical tweezer array, which enables the real-time interception and manipulation of circulating leukocytes in live animals. By utilizing intrinsic velocity differences between leukocytes and red blood cells, the system achieves stable trapping of individual leukocytes in vessels 15 - 20 μm in diameter and decelerates multiple cells in vessels greater than 20 μm. Notably, it also enables the optical blockage of lymphatic vessels exceeding 50 μm, a previously unreported capability. This label-free, non-invasive approach operates without repeated blood draws and is compatible with diverse vessel geometries and flow dynamics. The system offers a generalizable solution for in vivo cell extraction and analysis, paving the way for high-precision single-cell technologies in biomedical research and clinical translation.