Nanographene-Based\nPolymeric Nanoparticles as Near-Infrared\nEmissive Neuronal Tracers

Precise tracking\nof axonal transport is key to deciphering neuronal\nfunctions. To achieve long-term imaging at both ultrastructural and\nmacroscopic resolutions, it is critical to develop fluorescent transport\ntracers with high photostability and biocompatibility. Herein, we\nreport the investigation of nanographene (NG)-based polymeric nanoparticles\n(NPs) as near-infrared (NIR)-emissive neuronal tracers. Dibenzo[<i>a</i>,<i>m</i>]dinaphtho[3,2,1-<i>ef</i>:1′,2′,3′-<i>hi</i>]coronene (DBDNC)\nwas employed as the NG, which exhibited a broad NIR emission with\na maximum at 711 nm inside the NPs. DBDNC-NPs displayed high photostability\nand low cytotoxicity, enabling live tracing of retrograde axonal transport\nin mouse sensory neurons cultured in microfluidic chambers. We also\nelucidated how DBDNC-NPs undergo retrograde axonal transport following\nthe endolysosomal pathway. This work provides a proof of concept for\nNIR-emissive, NG-based neuronal tracers with potential for applications\nin neurobiology.