title: A mechanical characterization of polymer scaffolds and films at the macroscale and nanoscale.
abstract: Biomaterials should be mechanically tested at both the nanoscale and macroscale under conditions simulating their working state, either in vitro or in vivo, to confirm their applicability in tissue engineering applications. In this article, polyester-urethane-based films and porous scaffolds produced by hot pressing and thermally induced phase separation respectively, were mechanically characterized at both the macroscale and nanoscale by tensile tests and indentation-type atomic force microscopy. All tests were conducted in wet state with the final aim of simulating scaffold real operating conditions. The films showed two distinct Young Moduli populations, which can be ascribed to polyurethane hard and soft segments. In the scaffold, the application of a thermal cooling gradient during phase separation was responsible for a nanoscale polymer chain organization in a preferred direction. At the macroscale, the porous matrices showed a Young Modulus of about 1.5 MPa in dry condition and 0.3 MPa in wet state. The combination of nanoscale and macroscale values as well as the aligned structure are in accordance with stiffness and structure required for scaffolds used for the regeneration of soft tissues such as muscles.
authors.affiliation: Dipartimento di Ingegneria Meccanica e Aerospaziale, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Boffito
authors.forename: Ettore
authors.initials: E
authors.lastname: Bernardi
authors.forename: Susanna
authors.initials: S
authors.lastname: Sartori
authors.forename: Gianluca
authors.initials: G
authors.lastname: Ciardelli
authors.forename: Maria Paola
authors.initials: MP
authors.lastname: Sassi
mesh_terms: D001672:Biocompatible Materials; D055119:Elastic Modulus; D018625:Microscopy, Atomic Force; D011108:Polymers / Q000737:chemistry*; D054457:Tissue Scaffolds
chemical_list: D001672:Biocompatible Materials; D011108:Polymers
keywords: indentation-type atomic force microscopy; macroscale; mechanical properties; nanoscale; tissue engineering