Star PEG– from biofunctional coatings to 3D scaffolds for tissue engineering

POLY 370

Jürgen Groll, groll@dwi.rwth-aachen.de, DWI and der RWTH Aachen e.V, Pauwelsstrasse 8, 52074 Aachen, Germany, Paul D. Dalton, DWI an der RWTH Aachen e.V, Pauwelsstrasse 8, 52074 Aachen, and Martin Moeller, moeller@dwi.rwth-aachen.de, Institute of Technical and Macromolecular Chemistry, RWTH-Aachen University, Pauwelsstr. 8, Aachen, 52056, Germany.
Scaffolds formed through uniaxial freezing have a remarkable morphological similarity to the naturally formed scaffold for peripheral nerve regeneration over long distances, termed the Bands of Büngner. The process is inexpensive and simple to employ. We propose uniaxial freezing not of polymer solutions or during gelation of a hydrogel but within pre-formed hydrogels. For this purpose we use six arm star shaped prepolymers consisting of statistically polymerized ethylene oxide (EO) and propylene oxide (PO) in the ratio 4 to 1 and functional isocyanate (NCO) endgroups (star PEG). The star PEG system has successfully been applied as highly functional coatings system. Here we demonstrate that 3D gels can simply be manufactured by dissolving the material in water at a certain concentration. Oriented porous scaffolds can be created in pre-formed star PEG hydrogels by uniaxial freezing that show a remarkable morphological similarity to the Bands of Büngner.