Surfactant-free HEMA crystal colloidal paint for structural color contact lens.

Structural color originates from physical interactions of light with submicron ordered structures. Structural color is also the optimal candidate as a method for coloring contact lenses because of its vivid iridescence and being free of pigment. Here, we report a facile approach for fabricating a novel structural color contact lens by decorating with structural color paint through UV polymerization in a mould. The paints were fabricated by dispersing poly(methyl methacrylate-hydroxyethyl methacrylate) (PMH) nanoparticles in 2-hydroxyethyl methacrylate (HEMA) solvent without additional surfactants. The obtained structural color contact lenses showed high light transmission as well as gorgeous structural color, varying by adjusting the particle sizes. Moreover, cell viability assay and cell morphology observation revealed that the structural color contact lenses are cytocompatible. With high light transmission, gorgeous structural color, as well as good cytocompatibility, the structural color contact lenses are very promising as potential substitutes of traditional color contact lenses dyed by chemical pigments.