Special Poster Session Biofabrication
Over the last years, bioink development was one of the key aspects in the interdisciplinary field of biofabrication, especially for dispense plotting. Natural derived biopolymers are preferred as bioinks due to their often good cytocompatibility. However, in various applications scenarios, biopolymers also have limitations, such as suboptimal viscoelastic properties. Arguably, synthetic polymers can be tuned more easily for specific applications, in particular platforms that allow fine-tuning of physicochemical and viscoelastic properties are favourable. Poly(2-oxazoline)s are widely discussed as biomaterials in literature. Lorson et al. established a thermogelling (G´ ~ 4 kPa) and printable poly(2-oxazoline)/poly(2-oxazine) (POx/POzi) supramolecular hydrogel with defined, reversible and fast sol/gel transition. We recently investigated the inverse thermogelation properties of aqueous ABA triblock copolymers based on POx/POzi solutions into shear thinning and printable inks that feature a very large range of storage moduli (G´=0.1-110 kPa) and sol/gel transitions depending on polymer concentration and composition. Using these platforms as support materials in hybrid systems and support bath approaches during 3D bioprinting we demonstrate the advantages of different thermogelling structures. For advanced utilization of the described synthetic platforms as functional bioinks, two major limitations, namely long-term stability and biofunctionalization, have to be addressed. To introduce cell recognition peptide sequences and chemical crosslinking to ensure temporal mechanical control via Diels-Alder reaction, we adapted the well-established post polymerization modification (PPM) approach, and examined the influence of modification and crosslinking regarding printability, cross-linking kinetics and swelling followed by first long-term cell culture experiments using RGD-sequences as cell adhesion motives to ensure cell attachment of NIH 3T3 cells. In summary, we developed different physical hydrogels as support materials for bioprinting. Furthermore, via PPM we could overcome limitations regarding long term stability and bio-functionality to obtain a versatile synthetic bioink platform, applicable in many applications in the field of biofabrication.