2023, Rodriguez, Gabriela Melo, Trueb, Donata, Köser, Joachim, Schoelkopf, Joachim, Gullo, Maurizio

In this work we describe the manufacturing of cellulosic, cell compatible scaffolds with an inherent 3D origami crease pattern for applications in cardiac tissue engineering. Different cellulosic materials were studied, among them cotton linters, fibers obtained from eucalyptus, pine, spruce and lyocell. Formed sheets made of cotton linters were chosen for further study due to the highest biocompatibility and mechanical properties best suited for cardiomyocytes in wet and dry conditions: E - modulus of 0.8 GPa, tensile strength of 4.7 MPa and tensile strength in wet environment of 2.28 MPa. Cell alignment is desired to achieve directional contraction of the cardiac tissue, and several options were investigated to achieve fiber alignment, e.g. a dynamic sheet former and Rapid Köthen sheet former. Although the orientation was minimal, cells cultured on the cellulose fibers grew and aligned along the fibers. Origami inspired crease patterns were applied to the cellulose scaffolds in order to introduce directional flexibility beneficial for cardiac contraction. The transfer of a Miura-ori crease pattern was successfully applied in two ways: folding of the dried sheet between PET foils pre-formed in a 3D printed mold, and in situ wet fiber molding on a 3D-patterned mesh mounted in the sheet former’s sieve section. The latter approach enables upscaling for potential mass production.