Harnessing Supramolecular J-Aggregates in Deep Eutectic Solvents for Tunable NIR Photothermal and Photodynamic...

J-aggregates of cyanine dyes have emerged as powerful photothermal and imaging agents in the near-infrared (NIR) window due to their red-shifted absorption, narrow bandwidth, and strong excitonic coupling. However, their instability in biological environments often necessitates external carriers or stabilizers that compromise efficiency and biocompatibility. Here, we introduce deep eutectic solvents (DES) as a novel biocompatible medium to enhance the photothermal behavior of J-aggregates under NIR laser irradiation. Under 785 nm laser exposure, J-ICG_DES exhibited rapid, reproducible heating and resistance to disaggregation even at low dye concentrations. Additionally, we observed enhanced in vitro reactive oxygen species (ROS) generation for the J-ICG_DES formulation compared to J-ICG_water by employing a singlet oxygen quencher. This synergistic behavior translated into potent antimicrobial efficacy, achieving complete eradication of Staphylococcus aureus within 5 min of irradiation.