keywords AACHEN-KERATOPROSTHESIS ALPHACOR-KERATOPROSTHESIS BIOLOGICAL RESPONSE CROSS-LINKED COLLAGEN Engineering Engineering, Biomedical IMMOBILIZED POLY(VINYL ALCOHOL) IN-VIVO Life Sciences & Biomedicine Medicine, Research & Experimental NETWORK HYDROGELS Ophthalmology Research & Experimental Medicine SCAFFOLD SEOUL-TYPE KERATOPROSTHESIS Science & Technology TEMPORARY IMPLANT Technology artificial cornea collagen corneal cells corneal tissue engineering synthetic polymers