Volume Holographic Structuring of Special Hydrogel Films by Photochemical Crosslinking

Abstract

Multifunctional biomedical materials capable of integrating optical functions open up promising new possibilities for the application of photosensitive materials. For example, they are highly desirable for advanced intraocular lens (IOL) implants. For this purpose, we propose hydrogels, based on poly(ethylene glycol) (PEG) prepolymers, which are photochemically crosslinkable and thereby patternable. Various photoinitiators are used and investigated spectroscopically; those with high sensitivity in the optical region of the spectrum are advantageous. Hydrogel films have been obtained, which are applicable for light-based patterning and, hence, for functionalization of both surface and volume: It is shown that a local change in optical properties can be induced in special hydrogel films by photochemical crosslinking. Such a local light-induced material response forms the basis for volume holographic patterning. Cytocompatibility of hydrogels and compositions is evaluated via cytotoxicity tests. Exploiting the interrelationship between structure and function is highly relevant for biomedical materials with multifunctionality.