title: Indirect Rapid Prototyping: Opening Up Unprecedented Opportunities in Scaffold Design and Applications.
abstract: Over the past decades, solid freeform fabrication (SFF) has emerged as the main technology for the production of scaffolds for tissue engineering applications as a result of the architectural versatility. However, certain limitations have also arisen, primarily associated with the available, rather limited range of materials suitable for processing. To overcome these limitations, several research groups have been exploring novel methodologies through which a construct, generated via SFF, is applied as a sacrificial mould for production of the final construct. The technique combines the benefits of SFF techniques in terms of controlled, patient-specific design with a large freedom in material selection associated with conventional scaffold production techniques. Consequently, well-defined 3D scaffolds can be generated in a straightforward manner from previously difficult to print and even "unprintable" materials due to thermomechanical properties that do not match the often strict temperature and pressure requirements for direct rapid prototyping. These include several biomaterials, thermally degradable materials, ceramics and composites. Since it can be combined with conventional pore forming techniques, indirect rapid prototyping (iRP) enables the creation of a hierarchical porosity in the final scaffold with micropores inside the struts. Consequently, scaffolds and implants for applications in both soft and hard tissue regeneration have been reported. In this review, an overview of different iRP strategies and materials are presented from the first reports of the approach at the turn of the century until now.
authors.affiliation: Polymer Chemistry & Biomaterials Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000, Ghent, Belgium.
authors.forename: Annemie
authors.initials: A
authors.lastname: Houben
authors.affiliation: Polymer Chemistry & Biomaterials Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000, Ghent, Belgium.|Brussels Photonics Team, Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Belgium.
authors.forename: Jasper
authors.initials: J
authors.lastname: Van Hoorick
authors.affiliation: Brussels Photonics Team, Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Belgium.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Van Erps
authors.affiliation: Polymer Chemistry & Biomaterials Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000, Ghent, Belgium.|Brussels Photonics Team, Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Belgium.
authors.forename: Hugo
authors.initials: H
authors.lastname: Thienpont
authors.affiliation: Polymer Chemistry & Biomaterials Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000, Ghent, Belgium.|Brussels Photonics Team, Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Elsene, Belgium.
authors.forename: Sandra
authors.initials: S
authors.lastname: Van Vlierberghe
authors.affiliation: Polymer Chemistry & Biomaterials Group, Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000, Ghent, Belgium. peter.dubruel@ugent.be.
authors.forename: Peter
authors.initials: P
authors.lastname: Dubruel
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000627:therapeutic use*; D006801:Humans; D066330:Printing, Three-Dimensional; D011474:Prosthesis Design / Q000379:methods*; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials
keywords: Indirect 3D printing; Indirect rapid prototyping; Indirect solid free form fabrication; Lost-mould; Tissue engineering