3D Printed Polyurethane Scaffolds for the Repair of Bone Defects

Abstract

Critical-size bone defects are those that will not heal without intervention and can arise secondary to trauma, infection, and surgical resection of tumors. Treatment options are currently limited to filling the defect with autologous bone, of which there is not always an abundant supply, or ceramic pastes that only allow for limited osteo-inductive and-conductive capacity. In this study we investigate the repair of bone defects using a 3D printed LayFomm scaffold. LayFomm is a polymer blend of polyvinyl alcohol (PVA) and polyurethane (PU). It can be printed using the most common method of 3D printing, fused deposition modeling, before being washed in water-based solutions to remove the PVA. This leaves a more compliant, micro-porous PU elastomer. In vitro analysis of dental pulp stem cells seeded onto macro-porous scaffolds showed their ability to adhere, proliferate and form mineralized matrix on the scaffold in the presence of osteogenic media. Subcutaneous implantation of LayFomm in a rat model showed the formation of a vascularized fibrous capsule, but without a chronic inflammatory response. Implantation into a mandibular defect showed significantly increased mineralized tissue production when compared to a currently approved bone putty. While their mechanical properties are insufficient for use in load-bearing defects, these findings are promising for the use of polyurethane scaffolds in craniofacial bone regeneration.

The 3D Bioprinted Scaffolds for Wound Healing

“…They can be easily modified for improving physicochemical properties, and also functionalised with different molecules to meet particular requirements [215]. Among the synthetic polymers that are commonly printed are polylactic acid (PLA) [216], polyethylene glycol (PEG) [217], polycaprolactone (PCL) [218], polyglycolic acid (PGA) [219], polyurethane (PU) [220], and polylactic-co-glycolic acid (PLGA) [221].…”

Clinically relevant preclinical animal models for testing novel cranio‐maxillofacial bone 3D‐printed biomaterials

“…The most used cutting device for creating segmental defects in the mandibular is the reciprocating bone saw, which is mainly used for large animals 92,161 . The spherical burr, 162 diamond burr 163 and surgical drill 164 are also used for segmental defects in small animals. However, it is crucial that care must be taken to limit additional soft tissue damage during the procedure (e.g.…”

Recent Developments in Polyurethane-Based Materials for Bone Tissue Engineering

“…PU-based blends and composites can be processed into filament, pellets or powders to enable 3D scaffolds printing using high temperature melting-extrusion and sintering as well as dissolved in organic/aqueous solvents to allow micro extrusion-based 3D printing at low temperature [ 125 ]. Hence, Cooke et al [ 126 ] show that PU/PVA blends can be printed using themost 3D printing equipment to prepare 3D scaffold with promising properties for the craniofacial bone regeneration. Hung et al [ 127 ] prepared biodegradable waterborne PUs with PCL and poly(ethylene-butylene adipate) (PEBA) diols as soft segments in the form of NPs in water-based process.…”