A method of stabilizing riboflavin by affixing the riboflavin to at least one substrate for the riboflavin by covalent bonding, hydrogen bonding, Van der Waals forces, or a combination thereof, to form an optically-activated complex, is provided. When activated by absorption of light in the ultraviolet (UV) to visible region of the electromagnetic spectrum the riboflavin in the complex re-emits light of longer wavelength in the blue-green-yellow region of the electromagnetic spectrum.