Photodynamic treatment of acute vascular occlusion by using an iron–nitrosyl complex

Retinal vascular occlusion (RVO) is a common cause of visual impairment. Although several approaches, including vasodilators, have been explored to treat retinal vascular occlusion, there is no proper method to treat this obstruction today. We report a strategy that aims to pierce clogged blood vessels with a spatiotemporally controllable nitric oxide transporter, [Fe(TBDAP)(NO)(H2O)]2+ (1), which was synthesized and precisely characterized by various physicochemical methods, including X-ray crystallography. In the animal model, normal retinal blood vessels were confirmed to be dilated by the photoresponsive iron–nitrosyl complex. Furthermore, occluded retinal blood vessels were effectively reperfused after the immediate delivery of nitric oxide using light in animal disease models. These studies suggest an unprecedentedly selective and controllable treatment option for acute vascular occlusive diseases, including cardiovascular and cerebrovascular diseases.