Polaron engineering promotes NIR-II absorption of carbon quantum dots for bioimaging and cancer therapy

Menée à l'aide de lignées cellulaires et de modèles murins, cette étude présente une stratégie pour synthétiser des points quantiques de carbone capables d'absorber la lumière en proche infrarouge de type II (longueur d'onde : 1000-1700 nm) pour dégager de l'énergie thermique et émettre une fluorescence puis met en évidence l'intérêt de ces nanostructures pour la bio-imagerie et le traitement des cancers par photothermie

Résumé en anglais

Recent years have witnessed a surge of interest in tuning the optical properties of organic semiconductors for diverse applications. However, achieving control over the optical bandgap in the second near-infrared (NIR-II) window has remained a major challenge. To address this, here we report a polaron engineering strategy that introduces diverse defects into carbon quantum dots (CQDs). These defects induce lattice distortions resulting in the formation of polarons, which can absorb the near-field scattered light. Furthermore, the formed polarons in N-related vacancies can generate thermal energy through the coupling of lattice vibrations, while the portion associated with O-related defects can return to the ground state in the form of NIR-II fluorescence. On the basis of this optical absorption model, these CQDs have been successfully applied to NIR-II fluorescence imaging and photothermal therapy. This discovery could open a promising route for the polarons of organic semiconductor materials as NIR-II absorbers in nanomedical applications. Polaron engineering is a strategy for regulating the optical properties of nanomaterials.