Poly(2-Oxazolines) as Biomaterial ink and Bioink: from MEW printing vasculature to on-chip fabricationand in-flow 3D-printing of cell-laden microgel constructs

This lecture will focus on the exploitation of POx for biofabrication and show examples for the application of different POx-polymers as biomaterials inks as well as bioinks. The first part of the lecture will focus on Poly(2-n-propyl-2-oxazoline) and poly(2-cyclopropyl-2-oxazoline) as biomaterial inks for Melt-Electrowriting and show how these polymers and their (switchable) thermoresponsive solution behaviour can be used to generate microvascular structures within hydrogels or also collagen mimetic bundles of nanofibrils. The second part will introduce a random copolymer of 2-ethyl-2-oxazoline (EtOx) and 2-butenyl-2-oxazoline (ButEnOx) with variation of ButEnOx-content as UV-crosslinkable hydrophilic POx-bioink. This polymer was developed and tuned for the direct coupling of microfluidics and 3D-printing for the microfluidic production of cell-laden microgels with direct in-flow bioprinting into stable scaffolds. The methodology enables the continuous on-chip encapsulation of cells into monodisperse microdroplets with subsequent in-flow cross-linking to produce cell-laden microgels, which after exiting a microtubing are automatically jammed into thin continuous microgel filaments. The integration into a 3D printhead allows direct in-flow printing of the filaments into free-standing three-dimensional scaffolds