Vienna University of Technology

About: Vienna University of Technology is a education organization based out in Vienna, Austria. It is known for research contribution in the topics: Laser & Cloud computing. The organization has 16723 authors who have published 49341 publications receiving 1302168 citations.

Hydrogels for Two-Photon Polymerization: A Toolbox for Mimicking the Extracellular Matrix

Abstract: The natural extracellular matrix (ECM) represents a complex and dynamic environment. It provides numerous spatio-temporal signals mediating many cellular functions including morphogenesis, adhesion, proliferation and differentiation. The cell–ECM interaction is bidirectional. Cells dynamically receive and process information from the ECM and remodel it at the same time. Theses complex interactions are still not fully understood. For better understanding, it is indispensable to deconstruct the ECM up to the point of investigating isolated characteristics and cell responses to physical, chemical and topographical cues. Two-photon polymerization (2PP) allows the exact reconstruction of cell specifi c sites in 3D at micro- and nanometer precision. Processing biocompatible synthetic and naturally-derived hydrogels, the microenvironment of cells can be designed to specifi cally investigate their behavior in respect to key chemical, mechanical and topographical attributes. Moreover, 3D manipulation can be performed in the presence of cells, guiding biological tissue formation in all stages of its development. Here, advances in 2PP microfabrication of synthetic and naturally based hydrogels are reviewed. Key components of photopolymerizable hydrogel precursors, their structure–property relationships and their polymerization mechanisms are presented. Furthermore, it is shown how biocompatible 2PP fabricated constructs can act as biologically relevant matrices to study cell functions and tissue development.

Combining Ring-Opening Metathesis Polymerization (ROMP) with Sharpless-Type “Click” Reactions: An Easy Method for the Preparation of Side Chain Functionalized Poly(oxynorbornenes)

Abstract: Sharpless 1,3-dipolar cycloadditions (“click reactions”) between azides and acetylenes were used to prepare functional poly(oxynorbornenes) within their side chains. Two different strategies were applied to combine the preparation of ROMP polymers with the 1,3-dipolar cycloaddition approach: (a) the attachment of functional groups (i.e., hydrophobic and hydrogen bonding units) by 1,3-dipolar cycloaddition reactions to 7-oxynorbornenes bearing acetylenes and subsequent ROMP yielding the final polymers; (b) the ROMP polymerization furnishing first poly(oxynorbornenes) bearing acetylenic and azido moieties and subsequently attaching the functional units by use of the “click” reactions onto the modified polymers. Both strategies show efficient functionalization behavior with a high tolerance of functional groups with respect to the functional units attached as demonstrated by 1H and 13C NMR spectroscopy, opening the possibility to prepare a large variety of functionalized poly(oxynorbornenes) by use of only ...