Used as a lipophilic fluorescent tracer for cell membrane labeling in biological imaging. It integrates into lipid bilayers and allows long-term cell tracking due to its photostability and low cytotoxicity. Commonly applied in fluorescence microscopy and flow cytometry to monitor cell migration, fusion, and proliferation. Effective in both in vitro and in vivo studies, especially for neuronal tracing and tumor cell monitoring. Excited in the far-red to near-infrared range, enabling deep tissue imaging with minimal background autofluorescence.