Polybenzoxazines as new photothermal therapy agents

To make photothermal therapy an attractive alternative to conventional cancer treatments, the development of novel photothermal agents with enhanced properties is demanded. To tackle this challenge, herein we explored the use of polybenzoxazines, a well-known class of phenolic resins. Two different types of polybenzoxazine materials were prepared as potential photothermal agents: water-soluble polybenzoxazines as well as nanoparticles of hydrophobic polybenzoxazines, which can be generated in situ by polymer addition to cell culture medium. For both systems, irradiation with visible light led to significant photothermal effects, whose application to photoinduce human breast cancer cell's death was investigated in vitro. The best results were obtained for polybenzoxazine nanostructures, which exhibited successful cell internalization, minimal cytotoxicity in the dark and efficient photothermal killing of cancer cells upon illumination with high-penetrating red light. In combination with their low cost and facile preparation, this makes these polymer nanomaterials highly promising for photothermal therapy applications.