Physical characterization of 3D-printed gelatin and gelatin derivatives

Gelatin-based derivates, Gelatin Methacrylate (GelMA), has been recognised as the new and potential ways to encapsulate cells which shows promises in fabricating replaceable organs. Pluronics®, a synthetic polymer, has the property of reverse thermal gelation and the low toxicity which makes it popular for controlled protein delivery systems. In this study, it aims to develop an indirect extrusion bioprinting process via the use of sacrificial mould. For the experiments, 5% GelMA, 5% Cal-GelMA, 24.5% Pluronic and Plu-Alg are used to fabricate circular GelMA hydrogels. It is fabricated by extruding one layer of GelMA (or Cal-GelMA) and followed by, extruding one layer of Pluronic (or Plu-Alg) using a specific parameters. Before analysing the results, the rheology of pluronic of 20%, 24.5% and 30% and Plu-Alg were obtained. For the SEM and mechanical testing, the casting method of GelMa and Cal-GelMA were added. The SEM results showed that when printing Plu-Alg and Cal-GelMA, there will have marks left on the interface of the hydrogels which is caused by the Plu-Alg mould. Also, for the top surface of the hydrogels, all the samples have relatively non-porous surface with different degree of shrinkage due to drying process. Lastly, the mechanical testing tells that the hydrogels with highest compression modulus were prepared by 3D printing of Plu-Alg and Cal-GelMA. This is because of the formation of alginate gels with pluronic filling up the pores which decreases the diffusivity of the GelMA solution with the mould. By using Cal-GelMA instead of GelMA or using Pluronic as the mould, it lowered the compression modulus across all the samples.Bachelor of Engineering (Mechanical Engineering