Sacrificial 3D printing of shrinkable silicone elastomers for enhanced feature resolution in flexible tissue scaffolds

Elham Davoodi; Hossein Montazerian; Ali Khademhosseini; Ehsan Toyserkani

doi:10.1016/j.actbio.2020.10.001

Sacrificial 3D printing of shrinkable silicone elastomers for enhanced feature resolution in flexible tissue scaffolds

Acta Biomater. 2020 Nov:117:261-272. doi: 10.1016/j.actbio.2020.10.001. Epub 2020 Oct 6.

Authors

Elham Davoodi¹, Hossein Montazerian², Ali Khademhosseini², Ehsan Toyserkani³

Affiliations

¹ Multi-Scale Additive Manufacturing Lab, Mechanical and Mechatronics Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada; Department of Bioengineering, University of California, Los Angeles, 410 Westwood Plaza, Los Angeles, CA 90095, USA; Center for Minimally Invasive Therapeutics (C-MIT), California NanoSystems Institute (CNSI), University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, CA 90095, USA.
² Department of Bioengineering, University of California, Los Angeles, 410 Westwood Plaza, Los Angeles, CA 90095, USA; Center for Minimally Invasive Therapeutics (C-MIT), California NanoSystems Institute (CNSI), University of California, Los Angeles, 570 Westwood Plaza, Los Angeles, CA 90095, USA; Terasaki Institute for Biomedical Innovation, Los Angeles, CA 90024, USA.
³ Multi-Scale Additive Manufacturing Lab, Mechanical and Mechatronics Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada. Electronic address: ehsan.toyserkani@uwaterloo.ca.

PMID: 33031967
DOI: 10.1016/j.actbio.2020.10.001

Abstract

Silicone implants and scaffolds are emerging as potential replacement of flexible tissues, cosmetic and biomedical device implants due to their bioinert and flexible characteristics. The state-of-the-art direct-write silicone three-dimensional (3D) printers however cannot easily 3D print structures with sub-millimeter dimensions because of high viscosity and long curing times of their prepolymers. In the present study, a template-assisted 3D printing of ordered porous silicone constructs is demonstrated. The sacrificial molds were fabricated by low-cost and well-accessible material extrusion 3D printers. The 3D printed molds represent interconnected tortuous high specific surface area porous architectures based on triply periodic minimal surfaces (TPMS) in which the silicone prepolymer is cast and cured. We engineered silicone prepolymer with additives allowing on-demand structural shrinkage upon solvent treatment. This enabled 3D printing at a larger scale compatible with extrusion 3D printer resolution followed by isotropic shrinkage. This procedure led to a volumetric shrinkage of up to ~70% in a highly controllable manner. In this way, pore sizes in the order of 500-600 µm were obtained. The porous constructs were characterized with full strain recovery under extreme compressive deformations of up to 85% of the initial scaffold length. We further demonstrated the ability to infill cell-laden hydrogels such as gelatin methacryloyl (GelMA) into the interconnected pores while maintaining the cell viability of ~90%.

Keywords: 3D printing; Additive manufacturing; Mechanical properties; Shrinkage; Silicone; TPMS.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Gelatin
Porosity
Printing, Three-Dimensional
Silicone Elastomers*
Tissue Engineering
Tissue Scaffolds*

Substances

Silicone Elastomers
Gelatin