title: The stiffness and structure of three-dimensional printed hydrogels direct the differentiation of mesenchymal stromal cells toward adipogenic and osteogenic lineages.
abstract: The mechanical and physicochemical effects of three-dimensional (3D) printable hydrogels on cell behavior are paramount features to consider before manufacturing functional tissues. We hypothesize that besides good printability and cytocompatibility of a supporting hydrogel for the manufacture of individual tissues, it is equally essential to consider beforehand the desired tissue (bone, cartilage, fat). In light of its application, the structure and stiffness of printable hydrogel matrices influence cell geometry, which in turn impacts the differentiation fate. Embedded human mesenchymal stromal cells in printable type I collagen- and chitosan-agarose blends were induced to differentiate toward osteoblasts and adipocytes. Hydrogels' printability in air versus submerged printing in perfluorocarbon was evaluated according to the height, diameter, uniformity, and stability of 3D printed vertical cylinders. Bipotent differentiation within hydrogels was assessed histologically (morphology, cellularity), by immunohistochemistry (vimentin, smooth muscle actin), two-photon microscopy (spatial distribution), and real-time polymerase chain reaction (ALP, BGLAP, OPN, RUNX2, COL 1, aP2, PPARγ-2). Agarose and agarose blends revealed the most valid printability properties by generating uniform cylinders with an average height of 4 mm. Osteogenic differentiation was preferably achieved in anisotropic soft collagen-rich substrates, whereas adipogenic differentiation mostly occurred in isotropic stiff agarose-rich matrices. The conjugation of type I collagen to agarose with varying ratios is possibly a suitable bioink for a broad range of 3D printed mesenchymal tissues.
authors.affiliation: 1 Department of Dental Materials and Biomaterials Research, RWTH Aachen University Hospital , Aachen, Germany .
authors.forename: Daniela F
authors.initials: DF
authors.lastname: Duarte Campos
authors.forename: Andreas
authors.initials: A
authors.lastname: Blaeser
authors.forename: Anne
authors.initials: A
authors.lastname: Korsten
authors.forename: Sabine
authors.initials: S
authors.lastname: Neuss
authors.forename: Jörg
authors.initials: J
authors.lastname: Jäkel
authors.forename: Michael
authors.initials: M
authors.lastname: Vogt
authors.forename: Horst
authors.initials: H
authors.lastname: Fischer
mesh_terms: D017667:Adipocytes / Q000166:cytology; D050156:Adipogenesis / Q000502:physiology*; D001672:Biocompatible Materials / Q000138:chemical synthesis; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D019245:Compressive Strength; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D010006:Osteoblasts / Q000166:cytology; D010012:Osteogenesis / Q000502:physiology*; D066330:Printing, Three-Dimensional; D023822:Tissue Engineering / Q000295:instrumentation; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels