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Updated: May 27, 2025

A Bright NIR-II Fluorescence Probe for Vascular and Tumor Imaging
Published on: March 17, 2023
Naphthalimide Nanoprobe with Enhanced Electron-Withdrawing Ability and Large Stokes Shift for NIR-II Fluorescence
Min Peng1, Haoxuan Wei1, Qixuan Wang1
1State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
Abstract:
Nanoprobes with NIR-II fluorescence and a large Stokes shift are highly desirable for high-quality bioimaging applications. However, designing NIR-II fluorescent nanoprobes with the desired photophysical properties based on small organic molecules remains a significant challenge. Herein, we report a naphthalimide (NMI)-based NIR-II fluorescent molecule, NMI-BF2, by further enhancing the electron affinity of NMI through the incorporation of boron difluoride formazanate. NMI-BF2 exhibits a sufficient NIR-II quantum yield (QY) of 0.53%, a large Stokes shift of 263 nm, and excellent photostability. For biological applications, NMI-BF2 is coassembled with fetal bovine serum (FBS) to prepare a biocompatible nanoprobe, NMI-BF2/FBS, which maintains a good NIR-II QY of 0.21% and a photothermal conversion efficiency of 32.5%. In vitro and in vivo studies verified that the NMI-BF2/FBS nanoprobe shows an excellent photothermal antitumor therapeutic effect, guided by NIR-II fluorescence and photoacoustic imaging.

