Special Poster Session Biofabrication
The combination of bioprinting and additive manufacturing of a supporting polymer construct is a promising approach in the area of biofabrication to tailor the mechanical properties, enhance the structural integrity and improve the cell encapsulation of the employed low viscosity bioinks.1 Up to now, reported supporting materials are either hydrophobic semi-crystalline polymers with opaque properties, such as poly(ε-caprolactone) or materials which are chemically crosslinked after the printing process.2,3 There is a need for new polymers which can be processed from the melt with additive manufacturing techniques like extrusion-based 3D printing or melt electrowriting (MEW) and swell in aqueous media to hydrogels with adjustable mechanical properties.
Herein, we report the development of tailored (AB)n-segmented copolymers designed with polyethylene glycol (PEG) soft segments and thermoreversible physically crosslinked bisurea hard segments with n repeating units. The polymers were synthesized by step-growth polymerization from amino-terminated PEG (Jeffamine®, ED-900 g/mol) and either hexamethylene (HM) or 4,4’-methylene-bis(cyclohexyl) (mbCH) diisocyanate. The polymerization degree n was regulated by the addition of the monofunctional n-butylamine as terminating reagent in various equivalencies. Polymers with mbCH hard segments do not dissolve in aqueous media, but form stable hydrogels. Polymers with HM hard segments first swell but later slowly dissolve completely in aqueous media. We successfully prepared 3D scaffolds by both MEW and extrusion-based 3D printing. We see applications of these polymers as scaffolds or for the assembly of bioinks which will extend the biofabrication processing window.
1. Malda J.; Adv. Mater., 2013, 25, 5011.
2. Brown T.D.; Adv. Mater., 2011, 23,5651.
3. Chen F.; Biomacromolecules, 2016, 17, 208.