Plasmonic Copper Sulfide Nanocrystals Exhibiting Near-Infrared Photothermal and Photodynamic Therapeutic Effects

TLDR

Plasmonic copper sulfide nanocrystals have attracted attention for photothermal therapy, but prior studies linked cell death solely to heat and have not reported photodynamic effects. The study aimed to produce physiologically stable near‑infrared copper sulfide nanocrystals and evaluate their photothermal and photodynamic therapeutic potential in melanoma cells and a mouse model. The authors synthesized stable NIR‑responsive Cu₂₋ₓS nanocrystals and assessed their photothermal and photodynamic properties in vitro and in vivo. High PTT efficacy combined with intrinsic NIR photodynamic activity that generates reactive oxygen species was observed, alongside acute in vitro and in vivo toxicity, underscoring a NIR‑induced cancer therapy mechanism that may guide more effective nanotherapeutics.

Abstract

Recently, plasmonic copper sulfide (Cu2-xS) nanocrystals (NCs) have attracted much attention as materials for photothermal therapy (PTT). Previous reports have correlated photoinduced cell death to the photothermal heat mechanism of these NCs, and no evidence of their photodynamic properties has been reported yet. Herein we have prepared physiologically stable near-infrared (NIR) plasmonic copper sulfide NCs and analyzed their photothermal and photodynamic properties, including therapeutic potential in cultured melanoma cells and a murine melanoma model. Interestingly, we observe that, besides a high PTT efficacy, these copper sulfide NCs additionally possess intrinsic NIR induced photodynamic activity, whereupon they generate high levels of reactive oxygen species. Furthermore, in vitro and in vivo acute toxic responses of copper sulfide NCs were also elicited. This study highlights a mechanism of NIR light induced cancer therapy, which could pave the way toward more effective nanotherapeutics.