Novel small molecule-based organic nanoparticles for second near-infrared photothermal tumor ablation.

Second near-infrared (NIR-II,1000 âˆ¼ 1700 nm) therapeutic window presents an increased tissue penetration and elevated maximal permissible exposure in the application of photothermal therapy (PTT). However, the lack of NIR-II photothermal conversion agents (PCAs) limit their further development. In this work, we rationally designed and successfully developed three novel indolium-like heptamethine cyanine dyes (NFs) by installing N,N-diethylamino on the terminal ends of a conjugated polyene backbone and replacing the middle chlorine atom with o-mercapto benzoic acid and p-mercapto benzoic acid. Notably, NF2 with stronger rotating group encapsulated in organic nanoparticles (NF2 NPs) exhibited high photothermal conversion efficiency (PCE), which could come up to (61.3 %). Then we conducted serial experiments to further investigate PTT capability of NF2 NPs 4 T1 cell line and nude mice bearing 4 T1 tumor. As expected, the resulting NF2 NPs presented the excellent photothermal conversion ability and superb PTT effect both in vivo and in vitro. This study will inspire more work for future design and clinical applications of NIR-II therapeutic agents.

Tumor-Targeting Near-Infrared Dimeric Heptamethine Cyanine Photosensitizers with an Aromatic Diphenol Linker for Imaging-Guided Cancer Phototherapy.

Phototherapy is considered a promising alternative to conventional tumor treatments due to its noninvasive modality and effective therapeutic effect. However, designing a photosensitizer with satisfactory therapeutic effect and high security remains a considerable challenge. Herein, a series of dimeric heptamethine cyanine photosensitizers with an aromatic diphenol linker at the meso position is developed to improve the photothermal conversion efficiency (PCE). Thanks to the extended conjugate system and high steric hindrance, the screened 26NA-NIR and 44BP-NIR exhibit high PCE (≈35%), bright near-infrared (NIR) fluorescence, excellent reactive oxygen species (ROS) generation capability, and improved photostability. Furthermore, their outstanding performance on imaging-guided PDT-PTT synergistic therapy is demonstrated by in vivo and in vitro experiments. In conclusion, this study designs a series of dimeric heptamethine cyanine photosensitizers and presents two compounds for potential clinical applications. The strategy provides a new method to design NIR photosensitizers for imaging-guided cancer treatment.