In various embodiments, the present invention is directed to a facile one-pot reverse emulsion process to assemble core-shell nanoparticles (CS-SMNPs) into bright and noniridescent photonic supraballs. In one or more embodiments, the present invention is directed to core-shell nanoparticles having an inner high refractive index (RI) core and an outer low RI shell. In one or more embodiment, the present invention includes core-shell nanoparticles using high RI (1.74) melanin cores and low-RI (1.45) silica shells. In various embodiments, these nanoparticles may be self-assembled into bright and noniridescent supraballs using a scalable one-pot reverse emulsion process. According to various embodiments of the present invention, it is possible to generate a full spectrum of structural colors with the combination of only two ingredients, synthetic melanin and silica.