Preparation and Characterization of Tadpole- and Sphere-Shaped Hemin Nanoparticles for Enhanced Solubility

Hemin is a potent iron supplement. A major limitation of the applicability of hemin is its extremely low aqueous solubility and bioavailability. The aim of this work is to prepare hemin nanoparticles with improved solubility. Transmission electron microscopic images showed that hemin nanoparticles with different initial concentrations of hemin (0.1 and 0.5 mg/mL) were tadpole-shaped (head of approximately 200 nm and tail of 100 nm) and sphere-shaped (50-100 nm), respectively. Moreover, hemin nanoparticles exhibited higher solubility than free hemin. The solubility of sphere-shaped nanoparticles was 308.2-fold higher than that of pure hemin at 25 °C. The hemin nanoparticles were stable in acidic conditions and displayed excellent thermal stability. These results suggested that hemin nanoparticles could serve as a potential iron supplement with potential applications in the food, biomedical, and photodynamic-photothermal therapy fields.