Precision extruding deposition (PED) fabrication of polycaprolactone (PCL) scaffolds for bone tissue engineering

Abstract

Bone tissue engineering is an emerging field providing viable substitutes for bone regeneration. Recent advances have allowed scientists and engineers to develop scaffolds for guided bone growth. However, success requires scaffolds to have specific macroscopic geometries and internal architectures conducive to biological and biophysical functions. Freeform fabrication provides an effective process tool to manufacture three-dimensional porous scaffolds with complex shapes and designed properties. A novel precision extruding deposition (PED) technique was developed to fabricate polycaprolactone (PCL) scaffolds. It was possible to manufacture scaffolds with a controlled pore size of 350 microm with designed structural orientations using this method. The scaffold morphology, internal micro-architecture and mechanical properties were evaluated using scanning electron microscopy (SEM), micro-computed tomography (micro-CT) and mechanical testing, respectively. An in vitro cell-scaffold interaction study was carried out using primary fetal bovine osteoblasts. Specifically, the cell proliferation and differentiation was evaluated by Alamar Blue assay for cell metabolic activity, alkaline phosphatase activity and osteoblast production of calcium. An in vivo study was performed on nude mice to determine the capability of osteoblast-seeded PCL to induce osteogenesis. Each scaffold was implanted subcutaneously in nude mice and, following sacrifice, was explanted at one of a series of time intervals. The explants were then evaluated histologically for possible areas of osseointegration. Microscopy and radiological examination showed multiple areas of osseous ingrowth suggesting that the osteoblast-seeded PCL scaffolds evoke osteogenesis in vivo. These studies demonstrated the viability of the PED process to fabricate PCL scaffolds having the necessary mechanical properties, structural integrity, and controlled pore size and interconnectivity desired for bone tissue engineering.

Fabrication, mechanical and in vivo performance of polycaprolactone/tricalcium phosphate composite scaffolds

“…Wiria et al [23] reported on the in vitro cell ingrowth of PCL/HA scaffolds fabricated via SLS, however, even though the success of the addition of a bioactive phase is anticipated, the in vivo performance of such composite scaffolds has not been extensively reported. Reports on in vivo testing of PCL based scaffolds fabricated by other rapid prototyping techniques are limited to small animal models [30][31][32][33][34][35][36].…”

BMSCs-laden gelatin/sodium alginate/carboxymethyl chitosan hydrogel for 3D bioprinting

“…[35][36][37] Among them, the microextrusion bioprinters controlled by the extrusion of a material robotically with a microextrusion nozzle has been widely used in 3D bioprinter development. The stage or microextrusion head moves along x and y axis, in this way a layer is deposited as a foundation for the next layer when the extrusion head rises along z axis.…”

3D printing of hydrogel composite systems: Recent advances in technology for tissue engineering

“…Nozzle-based printing can be categorized into two groups: techniques with melting process and techniques without melting process. Nozzle-based printing with melting process include fused deposition modelling (FDM), precise extrusion manufacturing (PEM), multiphase jet solidification (MJS), precision extrusion deposition (PED), and 3D fiber deposition [31][32][33][34] . FDM technique is the most commonly used nozzle based 3D printing method in which thermoplastic filaments such as poly(lactice acid) (PLA) and acrylonitrile-butadienestyrene (ABS) are melted by heating and extruded on the build plate [35] .…”