Tissue engineering and regenerative medicine are currently seen as excellent alternatives for the rehabilitation or replacement of damaged tissues through the use of scaffolds. However, it is still a challenge that how to select materials and their manufacturing methods to fabricate tissue-adapted and customizable scaffolds. Biodegradable polymers with good biocompatibility, appropriate mechanical properties, easy processing and controlled degradation have attracted much attention. Herein, we aim to develop biodegradable and biocompatible polymers with customized mechanical properties and degradation time according to the target tissue, and to use them to manufacture customized and personalized scaffolds by 3D printing.
Firstly, biodegradable and biocompatible polycaprolactone-co-poly(ethyleneglycol)-co-polycaprolactone
(PCL-PEG-PCL) copolymers with adjustable mechanical properties were developed. They were synthesized by ring-opening polymerization (ROP) of Ɛ-caprolactone (Ɛ-CL) using PEG as an initiator. By adjusting the molecular weight, type and ratio of the initiator, the thermal properties and mechanical properties of PCL-PEG-PCL copolymer can be adjusted between a wide range to target different tissues. Degradation tests showed that the copolymers can maintain their shape for 3 months at 37 ℃ or 50 ℃, indicating good stability. Biological tests in vitro showed that the mitochondrial activity was always higher than 70 % and many cells with mononucleated, fibroblast-like shape appeared on the surface of materials, proving that PCL-PEG-PCL copolymers are non-toxic and have good cell compatibility and cell attachment.
Secondly, biodegradable, biocompatible and porous Poly (glycerol sebacate) (PGS) polymers with were obtained following different curing conditions. By adjusting curing conditions and pore size, the mechanical properties of porous PGS can be tailored and one of them reached an elastic modulus of 1 MPa which is close to that of muscle. Degradation test showed that PGS presents a faster degradation rate than PCL-PEG-PCL and was fully degraded after 1 month at 50 ℃ and after 3 months at 37 ℃.
Biological test in vitro also showed good cytocompatibility (higher than 70%) as well as cell attachment.
This first year assessment provides a material basis for the design and fabrication of scaffolds in tissue engineering. We will use 3D printing to fabricate scaffolds with complex shape and delve into degradation and biological properties in the following work.