Dopamine-Melanin Colloidal Nanospheres for MRI-Guided Photothermal Therapy

Abstract

Owing to high selectivity and minimal invasiveness, photothermal therapy is emerging as a powerful technique for cancer treatment. However, currently available photothermal therapeutic (PTT) agents have not yet achieved clinical implementation, stemming from great concerns regarding their long-term safety. From this point of view, we develop in this chapter a novel PTT agent based on dopamine-melanin colloidal nanospheres. Benefiting from wide distribution of their component in human naturally, this new PTT agent show biodegradability, a high median lethal dose, and does not induce long-term toxicity during their retention in rats. Moreover, this agent can offer much higher photothermal conversion efficiency than previously reported PTT agents. Upon irradiation with 808 nm laser, dopamine-melanin colloidal nanospheres can efficiently absorb light and transfer it into heat. Both in vitro and in vivo experiments prove that these nanospheres can destroyed tumor tissue and inhibit the regrowth of the tumor. Furthermore, dopamine-melanin colloidal nanospheres can be easily attached to conjugates with other interesting biofunctionalities. By covalent modification of Gd-DTPA, MRI-guided tumor targeted photothermal therapy is achieved.