*Article* **UV-VIS Curable PEG Hydrogels for Biomedical Applications with Multifunctionality**

**Tina Sabel-Grau \* , Arina Tyushina, Cigdem Babalik and Marga C. Lensen \***

Nanopatterned Biomaterials (Secr. C 1), Department of Chemistry, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany; arina1984@web.de (A.T.); cigdem7189@hotmail.de (C.B.) **\*** Correspondence: Tina@physik.tu-berlin.de (T.S.-G.); Marga@lensenlab.de (M.C.L.)

**Abstract:** Multifunctional biomedical materials capable of integrating optical functions are highly desirable for many applications, such as advanced intra-ocular lens (IOL) implants. Therefore, poly(ethylene glycol)-diacrylate (PEG-DA) hydrogels are used with different photoinitiators (PI). In addition to standard UV PI Irgacure, Erythrosin B and Eosin Y are used as PI with high sensitivity in the optical range of the spectrum. The minimum PI concentrations for producing new hydrogels with PEG-DA and different PIs were determined. Hydrogel films were obtained, which were applicable for light-based patterning and, hence, the functionalization of surface and volume. Cytotoxicity tests confirm cytocompatibility of hydrogels and compositions. Exploiting the correlation of structure and function allows biomedical materials with multifunctionality.

**Keywords:** hydrogels; photopolymers; volume holography; photo curing; multifunctional biomedical biomaterials; light-responsive materials
