Fabrication of synthesized PCL‐PEG‐PCL tissue engineering scaffolds using an air pressure‐aided deposition system

Bone tissue engineering is an emerging field providing viable substitutes for bone regeneration. Poly(ε‐caprolactone) (PCL) is a good candidate for scaffold fabrication due to its high mechanical strength and excellent resistance under moist conditions, but its hydrophobicity causes cell‐attached difficulties, thus limiting its clinical application. The paper aims to develop an air pressure‐aided deposition system for fabricating scaffolds made of synthesized PCL‐PEG‐PCL copolymers and to validate the biocompatibility and hydrophilicity improvement of fabricated scaffolds.

An air pressure‐aided deposition system that involves rapid prototyping technique has been developed to fabricate scaffolds for tissue engineering (TE) application. Poly(ethylene glycol) (PEG), a hydrophilic non‐ionic polymer, is adopted to reduce the hydrophobicity of PCL alone. The synthesis process of PCL‐PEG‐PCL copolymer is briefly introduced. Effect of viscosity in regard to scanning speed on the deposited strand is investigated. Scaffolds with different mean pore sizes are fabricated using the developed system. The fibroblast cells are seeded for culturing and biocompatibility of fabricated scaffolds are validated using methylthiazol tetrazolium assay.

The study finds that the air pressure‐aided deposition system is suitable for fabricating micro‐porous cellular scaffold, especially for thermal‐sensitive copolymers. In addition, the experimental results shows that at the molecular weight of 50,000, the molten form can be stably deposited through a heating nozzle at an air pressure of 0.3 MPa and no crack occurs after it solidifies. The scaffold with mean pore size of 339×396 μm is suitable for fibroblast binding and ingrowth. The synthesized copolymers are non‐toxic, biocompatible and can be used for biomedical application.

This study shows that weight ratio of PEG, 0.1, enhances the hydrophilicity of copolymer. Improvement regarding the weight ratio of PEG is necessary. Important challenges for further research are to optimize the fabrication parameter and pore interconnection for eliminating pore size error and enhancing cells proliferation, respectively.

An air pressure‐aided deposition system is successfully proposed to construct 3D tissue scaffolds. In addition, synthesized PCL‐PEG‐PCL copolymers are verified for biocompatibility and successfully fabricated into tissue scaffold with different mean pore sizes.