Northiosquaraine-Based Nanoparticles for Red-Light-Induced\nPhotodynamic Therapy via Singlet Oxygen Generation

Phototheranostics\nhave captured growing attention for their undenying\nsuperiority over traditional cancer therapy treatments. The integration\nof all phototheranostics modalities from ensuring near-infrared absorption-emission\nproperties to an efficient photodynamic therapy (PDT) behavior in\na single molecule is a challenging task. Herein, we have achieved\nthis by self-assembled northiosquaraine nanoparticles (TSQ-NPs) that\nexhibit high water dispersion ability, good biocompatibility, good\noptical behaviors, and a metal-free design. The synthesized TSQ-NPs\nhave been found to exhibit one of the highest values of singlet oxygen\nquantum yield and appreciable photostability among the reported organic\nnanoparticles. The <i>in vitro</i> studies of TSQ-NPs on\nKB and HeLa cells suggest efficient cell uptake within an hour, a\nstructure inherent mitochondrion targeting property, and ability to\nyield intracellular reactive oxygen species (ROS) under illumination\nof light that can be used for cell therapy applications. The excellent\nPDT effect induced by red light by nanoparticles originating from\na single organic compound is promising for the future of cancer diagnostics,\ntherapy, and molecular imaging.