Dispensing of hydrogel ink onto electrospun biodegradable paper for biomedical applications

In this contribution we present the development of a biobased hybrid material made from a mechanically stable, paper-like fleece combined with a hydrogel, which mimics the extracellular matrix (ECM) of soft tissue. We used methacryl-modified gelatin as described earlier for the formulation of dispensable hydrogel precursor-solutions (bioinks). By variation of the degree of modification we provided viscous liquid inks and physically gelling inks. After deposition, such bioinks could be chemically crosslinkend by UVB irradiation to form non-soluble hydrogels. We produced cell-free hydrogels as well as hydrogels loaded with human fibroblasts from skin biopsies. Freeform fabrication of thin hydrogel-coatings or of three-dimensional (3D) hydrogel constructs was achieved by application of digital 3D printing (bioprinting). For stabilization of the hydrogels we used fleece substrates produced from the biodegradable polymer poly (L-lactide) (PLA) and the modified biopolymer gelatin by electrospinning. The presence of the biomolecule component in the fleece added a more hydrophilic character to the PLA non-wovens, which was crucial for stable bonding of hydrogel and fleece.