Self-assembly induced dual-wavelength active photothermal and photodynamic therapies using a near-infrared triimide dye nanoformulations

Cancer, a significant global health burden, necessitates holistic strategies due to disparities in early detection and treatment. Existing therapies have limitations, leading to the exploration of nano-mediated therapies like photothermal therapy (PTT) and photodynamic therapy (PDT). In this context, we address the need for improved agents by introducing a novel near-infrared (NIR) absorbing triimide dye, Eh-G, synthesized through a one-step Diels-Alder reaction from perylene diimides. Although Eh-G is toxic and hydrophobic, its liposome encapsulation enhances solubility in water and its biocompatibility and bioavailability in cells. The liposomal nanoformulations of Eh-G (L-Eh-G) show excellent photothermal conversion efficiency up to 42.9% under 750 nm irradiation. As a result, it effectively causes cell death in triple-negative breast cancer cell line 4T1. Interestingly, Eh-G self-assembles into nanofibers in water with red-shifted absorption beyond 800 nm. This leads to the PTT effect of L-Eh-G under 808 nm laser irradiation without compromising on photothermal conversion efficiency. Moreover, L-Eh-G also efficiently generates reactive oxygen (ROS) under both 750 nm and 808 nm laser irradiations. Thus, our study highlights Eh-G's potential for combined photothermal and photodynamic cancer therapy with dual wavelength activity, bridging a crucial knowledge gap and showcasing its promise for further development in cancer therapeutics.