Synthesis and characterization of photopolymerizable triblocks for 3D printing tissue engineering scaffolds

Abstract

While previous research on polycaprolactone (PCL) and polyethylene glycol (PEG) triblock copolymers has focused on their use as hydrogels or with conventional scaffold fabrication methods, this work concentrates on producing viable photocurable resins from synthesized triblocks for use in a layer-by-layer 3D printer. After successful synthesis of PCL-PEG-PCL and PCL-PEG-PCL-diacrylate triblocks, they were combined with (hydroxyethyl)methacrylated polyethylene glycol (PEG-HEMA) and used as biomaterials in a dynamic masking 3D printing system to fabricate porous scaffolds. Diacrylation of the polymer (PCL-PEG-PCL-DA) revealed a substantial increase in mechanical strength and resulting compound resolved the re-dissolving issue significantly during the 3D printing process. Degradation tests were carried out by incubation in phosphate-buffered saline, and both biomaterials demonstrated their degradation resistance with steady pH levels and mass loss plateauing at 20% over a sixty day timeframe. Preliminary MG63 cell culture tests on the cross-linked 3D porous structures showed no significant cytotoxicity and MTT assay data verified cell proliferation on the photocured samples after three days. As a result, end-capping PCL-PEG-PCL with acrylates demonstrated advantages over PCL-PEG-PCL while keeping similar performance in degradation and biocompatibility. Overall results from this work demonstrate the suitability of the novel triblocks for use as biomaterials in tissue engineering scaffolds.