An Easily Accessible NIR‐Absorbing Tetraimide Dye and its Biotherapeutics Based Photothermal and Photodynamic Therapy

Abstract

AbstractOrganic π‐systems with strong absorption in the near‐infrared (NIR) region are promising candidates for photothermal therapy (PTT) and photodynamic therapy (PDT). However, the synthesis of NIR π‐systems involves several steps and many of them display poor photothermal conversion efficiency (PTCE). Here we present the synthesis of a tetraimide‐based donor‐acceptor NIR π‐system, 2EHex‐B having absorbance in the range of 350–900 nm. Importantly, 2EHex‐B is synthesized in two steps with a 70 % high yield. Moreover, 2EHex‐B shows excellent PTCE up to 50 % and good biocompatibility when encapsulated in liposomes. The liposome coated 2EHex‐B, (L‐2EHex‐B) showed good thermal stability and efficiently kills cancer cells via PTT. Additionally, L‐2EHex‐B shows good reactive singlet oxygen generation ability when irradiated with a 750 nm laser. 3D cell culture model ‐ multicellular spheroids test was performed to evaluate the efficiency of PTT. The spheroids treated with L‐2EHex‐B after NIR light irradiation showed increased cell death from the core of the tumor toward the periphery. The easy access to 2EHex‐B makes it a potential candidate for minimally invasive cancer treatment.