Solid freeform fabrication and in-vitro response of osteoblast cells of mPEG-PCL-mPEG bone scaffolds

Abstract

Bone tissue engineering is an emerging approach to provide viable substitutes for bone regeneration. Poly(ethylene glycol) (PEG) is a good candidate of bone scaffold because of several advantages such as hydrophilicity, biocompatibility, and intrinsic resistance to protein adsorption and cell adhesion. However, its low compressive strength limits application for bone regeneration. Poly(ε-caprolactone) (PCL), a hydrophobic nonionic polymer, is adopted to enhance the compressive strength of PEG alone.We aimed to investigate the in-vitro response of osteoblast-like cells cultured with porous scaffolds of triblock PEG-PCL-PEG copolymer fabricated by an air pressure-aided deposition system. A desktop air pressure-aided deposition system that involves melting and plotting PEG-PCL-PEG was used to fabricate three-dimensional scaffolds having rectangular pores. The experimental results showed that PEG-PCL-PEG with a molecular weight of 25,000 can be melted and stably deposited through a heating nozzle at an air pressure of 0.3 MPa and no crack occurs after it solidifies. The scaffolds with pre-determined pore size of 400× 420 μm and a porosity of 79 % were fabricated, and their average compressive strength was found to be 18.2 MPa. Osteoblast-like cells, MC3T3-E1, were seeded on fabricated scaffolds to investigate the in-vitro response of cells including toxicity and cellular locomotion. In a culture period of 28 days, the neutral-red stained osteoblasts were found to well distributed in the interior of the scaffold. Furthermore, the cellular attachment and movement in the first 10 h of cell culture were observed with time-lapse microscopy indicating that the porous PEG-PCL-PEG scaffolds fabricated by air pressure-aided deposition system is non-toxicity for osteoblast-like cells.

The Osteogenesis of Bone Marrow Stem Cells on mPEG-PCL-mPEG/Hydroxyapatite Composite Scaffold via Solid Freeform Fabrication

“…The mPEG-PCL-mPEG triblock polymer was synthesized as in previous report [7]. In brief, the diblock copolymers were synthesized by ring-opening polymerization of ε -caprolactone in the presence of mPEG-OH as a macroinitiator with Sn(Oct) 2 serving as a catalyst.…”

“…A desktop air pressure-aided deposition system was used for this study as in previous report [7]. The hardware component consists of an XYZ position system, a material heating module, a temperature control system, and an air pressure control system with an air compressor machine.…”

“…In this study, we have tailor-made an air pressure-aided deposition (APAD) system to fabricate the BTE scaffold [7]. Previously, we have demonstrated the successful scaffold fabrication by APAD with biodegradable mPEG-PCL-mPEG triblock (PCL) copolymers and mPEG-PCL-mPEG/hydroxyapatite (PCL/HA) biocomposite [7].…”

“…Previously, we have demonstrated the successful scaffold fabrication by APAD with biodegradable mPEG-PCL-mPEG triblock (PCL) copolymers and mPEG-PCL-mPEG/hydroxyapatite (PCL/HA) biocomposite [7]. Both scaffolds were shown to provide good support for osteoblasts' attachment and proliferation.…”

Nanoengineered biomaterials for repair and regeneration of orthopedic tissue interfaces

“…To overcome these limitations, recent approaches have shifted towards additive manufacturing. Some of the additive manufacturing approaches that can be used to engineer interface tissues include 3D printing, [133][134][135] stereolithography, air pressure aided deposition, [136,137] and robotic dispensing [138][139][140]. These freeform prototyping techniques face problems of bio-printability, which limit the use of printing cells with the scaffolds.…”