Abstract
Near-infrared-II carbon dots offer exceptional deep-tissue penetration for biomedical imaging, but challenges remain in their synthesis and photoluminescence mechanisms. Here, we report three carbon dots (CDs-1, CDs-2, CDs-3) with tunable emission from the visible to the Near-infrared-II (480–1265 nm), synthesized by constructing extended aniline-based frameworks from p-phenylenediamine. Combined structural and density functional theory analyses reveal that the Near-infrared-II redshift arises from the enhanced molecular dipole moments and electron-acceptor ability of the precursor, as well as the accumulation of graphene domains and pyrrolic nitrogen doping during carbonization polymerization, which collectively drive the narrowing of the energy gap. CDs-3 shows 15 mm penetration depth in gallbladder Near-infrared-II imaging (vs. clinically used indocyanine green 2 mm). With 1.44 signal-to-noise ratio and 334.5 μm resolution, it enables precise monitoring of biliary strictures/leakage. Selenium-doping-derived functionalized composite nanomaterials (CDs-3@pPB) exhibit potent reactive oxygen species scavenging and theranostic efficacy in liver fibrosis. This work elucidates the mechanism underlying the redshift of carbon dots emission into the Near-infrared-II and establishes a nanoplatform for hepatobiliary theranostics, demonstrating substantial clinical potential.
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All data are available in the main text or the supplementary materials. The atomic coordinates of the optimized computational models reported in this paper have been deposited in the figshare database under the (https://doi.org/10.6084/m9.figshare.30889529). Any additional data supporting the findings of this study are available from the corresponding authors upon request. Source data are provided with this paper.
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Acknowledgements
This work was supported by the National Key Research and Development Program of China (2023YFB3810000 [G.L.], 2023YFC2415700[Z.L.]), the National Natural Science Foundation of China (U22A20333[G.L.], U24A20525[G.L.], 32571591[Z.L.]), Xiang’an Innovation Laboratory Science and Technology Project (2024XAKJ0102008[Z.L.]), Xiamen Natural Science Foundation of China (3502Z202572009[G.L.], 2024Y9716[G.L.], 2025XAKJ0201002[Z.L.]), the Fundamental Research Funds for the Central Universities (20720240051[Z.L.]), the Clinical Research Center for Radiation and Therapy Open Project Innovation Team Project of Sichuan Province (2024ZX02[G.L.] and 2024YBUYXJJ051[G.L.]), and the Program for New Century Excellent Talents in University, China (NCET-13-0502) [G.L.].
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L.Y.: Writing original draft, Project administration, Methodology, Investigation, Conceptualization. M.Li.: Writing original draft, Methodology, Investigation, Conceptualization. Y.P.: Writing–original draft, Project administration, Methodology, Data curation. Y.Z.: Resources, Methodology, Formal analysis. J.Z.: Resources, Methodology, Formal analysis. H.L. and W.Z.: Supervision, Methodology, Formal analysis. J.L. (Jie Liu), P.H., F.D., J.Z. and J.L. (Jing Lin): Resources, Investigation. G.L., Z.L., S.Q.: Writing–review & editing, Writing–original draft, Funding acquisition, Data curation.
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Yang, L., Li, M., Peng, Y. et al. Engineering NIR-II carbon dots through aniline extension with graphene and nitrogen enrichment for hepatobiliary theranostics. Nat Commun (2026). https://doi.org/10.1038/s41467-026-70150-7
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DOI: https://doi.org/10.1038/s41467-026-70150-7
