Robust Packing of a Self-Assembling Iridium Complex via Endocytic Trafficking for Long-Term Lysosome Tracking

Live cell imaging of lysosome positioning and motility is critical to studying lysosome status and function for pharmacological interventions. To create a super stable lysosomal probe for long-term live cell imaging, we have designed and synthesized an aromatic-peptide-conjugated cyclometalated iridium(III) complex that emits light via pi-pi stacking oriented self-assembly in water at extremely low concentration. Through endocytic trafficking, self-assemblies are transformed from nanoparticles into sturdily packed networks that are stabilized in lysosomal acidic environment. Upon short time/low dose treatment of the iridium complex at passage 0, live cell lysosomal tracking is applicable beyond the 14th passage of cells with high labelling rate and a mild decline in luminescence intensity. The illuminated lysosomes are trackable using super-resolution imaging to study their response to cellular processes.

Automated summary

A novel lysosomal probe was designed and synthesized in this study, which self-assembles into stable network structures at extremely low concentrations, enabling long-term live cell imaging. This probe can efficiently label lysosomes in cells up to the 14th passage with minimal impact on luminescence intensity, and illuminated lysosomes are trackable using super-resolution imaging to study their response to cellular processes.