Chirality is widespread in nature and governs the properties of various materials including inorganic nanomaterials. However, previously reported chiral inorganic materials have been limited to a handful of compositions owing to the physicochemical restrictions that impart chirality. Herein, chiral nanopaint applicable to diverse inorganic materials is presented. Various metal oxide nanoparticles (NPs) show chiroptical properties after coating with our chiral nanopaint, while maintaining their properties, such as magnetic properties. The combination of magnetism and chirality brings biomedical functionalities to chiral NPs, such as anticancer hyperthermia treatment. In vitro, d-nanopainted iron oxide NPs showed more than 50% higher cellular uptake compared to l-nanopainted iron oxide NPs, and this was due to the enantiospecific interaction between the cellular receptors on the cell surface and the chiral NPs. In vivo, d-nanopainted iron oxide NPs showed 4-fold superior anticancer efficiency by magnetic hyperthermia compared to l-nanopainted iron oxide NPs owing to improved adsorption to tumors. These chiral nanoparticles may provide potential synthesis strategies for chiral inorganic biomaterials, which exhibit elaborate combinations of intrinsic physical properties and extrinsic enantioselective properties for a variety of applications.
Keywords: anticancer; biomaterials; chirality; hyperthermia; metal oxides.