Abstract

3D Bioprinting with Stem Cells for Soft Tissue Engineering

Paul Gatenholm, Professor/Director of 3D Bioprinting Center, Chalmers University Sweden

The introduction of 3D bioprinting is expected to revolutionize the field of tissue engineering and regenerative medicine, which enables the reconstruction of living tissue and organs using the patient’s own cells. We have developed novel bioinks based on polysaccharide nanofibrils with unique combination of printing fidelity good mechanical properties and biocompatibility. Nanofibril dispersion have extremely shear thinning properties and high zero shear viscosity. 3D bioprinting fidelity which is achieved with these bioinks made it possible to print complex cartilage tissue shapes such as ear, nose and meniscus. We have also studied addition of the second polysaccharide such as alginate and hyaluronic acid to achieve crosslinking after bioprinting. Crosslinked structures exhibit an excellent shape and size stability and good mechanical properties. The most challenging part has been to secure good cell viability during printing of cell-laden hydrogel constructs using ink jet printing head. Different procedures of mixing of bone marrow derived mesenchymal stem cells have been evaluated and viability of cells was evaluated using live-dead assays. The shear thinning properties of NFC with orientation of nanofibrils during the printing operation made it possible to achieve high cell viability. The bioprinted cell-laden NFC constructs were cultivated in in vitro culture and showed remarkable cell proliferation and growth of human cartilage tissue. The preclinical evaluation has been initiated in collaboration with plastic surgeons and we see great future for 3D bioprinting of soft tissue such as skin, cartilage and adipose tissue using stem cells and polysaccharide bioinks which are now in translation under trade name CELLINK.