Significant increase in the water dispersibility of zinc phthalocyanine nanowires and applications in cancer phototherapy

Hee Cheul Choi, Sang Ho Lee and co-workers have devised a way to improve the dispersibility of light-sensitive molecules in water. Using light to treat medical conditions, including tumours, can be less invasive and toxic than other approaches. Such photodynamic and photothermal therapies rely on a light-sensitive molecule — a photo-sensitizer — that is excited under irradiation to release either reactive oxygen species or heat, respectively, which in turn can destroy targeted cells. Most photo-sensitizers, however, suffer from poor solubility in aqueous physiological media, which hinders their applications in the body. This is the case for zinc phthalocyanine, a macrocyclic compound hosting a zinc atom in its central cavity. Rather than trying to alter its chemical composition, the researchers have now observed that converting the powder form into crystalline nanowires significantly increased its dispersibility in water. Furthermore, the nanowires were found to be promising for both photothermal and photodynamic therapies.