A method and an apparatus for providing an emotion expression service in a mobile communication terminal are provided. The light guide plate manufacturing apparatus includes a stage supporting a substrate for manufacturing the light guide plate, a screen disposed on the substrate supported by the stage, an applying part applying an etching ink onto the screen, and a squeegee pressurizing the screen with the etching ink applied thereon to form a pattern corresponding to a screen pattern in the substrate. The magneto resistive effect elements output resistance values which vary in accordance with a direction of a magnetic field to be input, and are arranged such that fixed magnetization directions of all magneto resistive effect elements are in the same direction. The video program URL is converted into a simple code, and the code is invisibly embedded by steganography in a video program which is being broadcasted. The method involves administering to a cell a hydrogel in which a therapeutic compound is noncovalently bound to heparin.