Developing nanophotothermal agents (PTAs) with satisfied photothermal conversion efficiency (PTCE) in the second NIR window (1000-1350 nm, NIR II) holds great promise for enhanced photothermal therapy effect. Herein, we develop a NIR-II PTA with advanced PTCE, based on a new two-dimensional ultrathin tellurium oxide/ammonium tungsten bronze (TeO2/(NH4) xWO3) nanoribbons (TONW NRs). The doped ammonia ions-mediated-free-electrons injection into the lowest unoccupied molecular orbital band of WO3 combined with the electronic transitions between W6+ ions and the lone pair of electrons in Te atoms achieve excellent NIR absorption of TONW NRs resulting from localized surface plasmon resonance. The polyethylene glycol functionalized TONW NRs (PEG-TONW NRs) exhibit good stability and biocompatibility, displaying a PTCE high to 43.6%, surpassing many previous nano-PTAs active in the NIR II region, leading to remarkable tumor ablation ability both in vitro and in vivo. Meanwhile, advanced X-ray computed tomography (CT) and photoacoustic (PA) imaging capability of PEG-TONW NRs were also realized. Given the admirable photothermal effect in NIR II region, good biocompatibility, and advanced CT/PA imaging diagnosis capability, the novel PEG-TONW NRs is promising in future personalized medicine applications.
Keywords: Ammonium tungsten bronze; multimodal imaging; photothermal therapy; tellurium oxide; the second NIR window; two-dimensional nanomaterials.