Advanced cell-instructive photo-hydrogels for laser-based high-resolution 3D printing

Elucidating the mechanisms of mammalian cell interaction of with their surrounding matrix is one of the biggest scientific challenges of modern times. The knowledge gained from such research has an enormous innovative potential and would benefit a number of critical areas including drug development, regenerative medicine, and studies of disease progression. Possibility to reproduce natural cell culture conditions in vitro would greatly accelerate such research by enabling systematic studies in well-controlled and reproducible manner. The main objective of this proposal is to develop a material toolkit enabling realization of precisely engineered biomimetic artificial 3D cell culture matrices. The two-photon polymerization (2PP) technique will be used to noninvasively pattern cell- containing hydrogels in 3D. The material concept is based on combination of naturally-based (collagen derived) and synthetic poly(2-oxazoline)s (PAOx) hydrogel precursors. These compounds will be modified with reactive groups that undergo radical chain growth polymerization. In addition to classical (meth)acrylate chemistry, a new generation of biocompatible polymerizable groups based on vinylesters will be utilized. In parallel, novel water-soluble photoinitiators based on a chromophore involving a cleavable 1,4-pentazadiene-core (PADE) will be developed. The resulting photosensitive hydrogels will enable realization of complex structures via high resolution 3D printing based on 2PP. Most importantly such innovative hybrid gels exhibit a number of relevant properties: 1) adjustable cell adhesion and biodegradation properties; 2) precise control of local mechanical properties within the structure; 3) well-defined thermoresponsive behavior, adding an independent degree of freedom for 3D printing. After initial characterization these materials will be used to establish procedures for local tuning of mechanical properties of produced structures on a sub- cellular level in 3D by adjusting the parameters of 2PP processing. As a proof-of-principle the correlations between response of stems cells and hydrogel matrix properties will be evaluated. The envisioned developments will facilitate realization of elegant biological in vitro experiments, helping to elucidate biomimetic aspects of cell interaction with the surrounding environment. Furthermore, availability of physiologically relevant cell cultures will help to reduce the need for animal studies.

The project "Advanced cell-instructive photo-hydrogels for laser-based high-resolution 3D printing" was conducted in collaboration between TU Wien (Vienna, Austria), Ghent University (Gent, Belgium) and Vrije Universiteit Brussel (Brussels, Belgium). In the course of the project several novel photosensitive formulations designed for biomedical applications were developed. Among other breakthroughs these materials enabled high-resolution bioprinting using two-photon polymerization (2PP) technology. The results of the project were reported at multiple international conferences and made available vie the open access peer-reviewed publication.