title: Three-dimensional printing of complex biological structures by freeform reversible embedding of suspended hydrogels.
abstract: We demonstrate the additive manufacturing of complex three-dimensional (3D) biological structures using soft protein and polysaccharide hydrogels that are challenging or impossible to create using traditional fabrication approaches. These structures are built by embedding the printed hydrogel within a secondary hydrogel that serves as a temporary, thermoreversible, and biocompatible support. This process, termed freeform reversible embedding of suspended hydrogels, enables 3D printing of hydrated materials with an elastic modulus <500 kPa including alginate, collagen, and fibrin. Computer-aided design models of 3D optical, computed tomography, and magnetic resonance imaging data were 3D printed at a resolution of ~200 μm and at low cost by leveraging open-source hardware and software tools. Proof-of-concept structures based on femurs, branched coronary arteries, trabeculated embryonic hearts, and human brains were mechanically robust and recreated complex 3D internal and external anatomical architectures.
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Hinton
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Quentin
authors.initials: Q
authors.lastname: Jallerat
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Rachelle N
authors.initials: RN
authors.lastname: Palchesko
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Joon Hyung
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Grodzicki
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Hao-Jan
authors.initials: HJ
authors.lastname: Shue
authors.affiliation: Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Mohamed H
authors.initials: MH
authors.lastname: Ramadan
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Hudson
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA. ; Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Adam W
authors.initials: AW
authors.lastname: Feinberg
keywords: 3D printing; alginate; biomimetic; collagen; fibrin; heart; hydrogels; perfusable vasculature; tissue engineering