Mitochondria-Targeted BODIPY Nanoparticles for Enhanced Photothermal and Photoacoustic Imaging In Vivo.

Short-wavelength absorption and emission (<600 nm), hydrophobicity, and low selectivity have greatly restricted the biomedical applications of BODIPY. Herein, a series of mitochondria-targeted BODIPY nanoparticles with a cationic triphenylphosphine (TPP) group ( NPs) bearing different lengths of ethylene glycol (0-4 units), along with without a cationic TPP group for comparison, have been rationally designed and prepared to investigate the interplay between their structures and the related properties. Our studies found that NPs showed a tendency of aggregation and precipitation while NPs could be stable in aqueous solutions. Compared with , tailor-made possessed a high photothermal conversion efficiency (PCE) of 76.6 vs 9.0% and exhibited the highest photoinduced cytotoxicity. Upon NIR irradiation, the temperature induced by NPs increased rapidly from room temperature to 76.0 °C in vitro and 50.0 °C at the tumor site in vivo within 5 min. Furthermore, effective mitochondrial imaging in vitro, photothermal imaging (PTI), and photoacoustic imaging (PAI) in vivo were achieved. In this paper, we developed tailor-made photothermal agents for targeting mitochondria and enhancing the PTI and PAI performances, which could be potentially applied in clinical precision theranostics.