NIR-IIb fluorescence ratiometric imaging of tumor-associated neutrophils for immunotherapy efficacy monitoring and strategy optimization.

ABSTRACT: Imaging the immune activation status of tumor-associated neutrophils (TANs) provides insights into cancer immunotherapeutic strategy improvement. Here we show a ratiometric nanoprobe responding to tumor microenvironment and enabling NIR-IIb quantitative fluorescence imaging of TANs with overexpression of neutrophil elastase (NE). The ratiometric nanoprobe integrates erbium-based nanoparticles (ErNPs) with NE-cleavable peptide-caged near-infrared-II (NIR-II) fluorescence dye. Upon systemic delivery, the nanoprobe actively targets tumor microenvironment, where NE cleaves the caging peptide to trigger energy transfer within ErNPs under 808 nm excitation, yielding enhanced NIR-IIb fluorescence emission at 1532 nm. In contrast, the NE-independent fluorescence of ErNPs at 1532 nm remains stable

SUBMITTER: Li Y 

PROVIDER: S-EPMC12680687 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature