Printability study of the bioink for bioprinting

• Main Author: Ho, Nicolette Yi Ting
• Other Authors: Chua Chee Kai
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/74314
• Institution: Nanyang Technological University

Advancement in 3D bioprinting has enabled this technology to be used in various biomedical applications. One possible use of 3D bioprinting is for spinal cord regeneration. To date, there is still no robust treatment discovered which restores the loss of function due to spinal cord injury (SCI). 3D bioprinting, with its ability to fabricate complex and complicated structures, could be a possible method for fabricating nerve scaffolds that can be used for spinal cord regeneration. In this study, two biomaterials, Gelatin methacryloyl (GelMA)-gellan gum (GG) composite and Pluronic F127, were printed simultaneously using an extrusion bioprinter to create a nerve scaffold consisting of two different materials. Pluronic F127 was rinsed away with water to create a desired construct consisting of hollow channels. Different concentration ratios of GelMA and GG were mixed to create the GelMA-GG composite. For the experiments, the GelMA/GG concentrations used were 7.5/0.1%, 7.5/0.2% and 7.5/0.5% w/v. The properties of the GelMA-GG composite were investigated using Scanning Electron Microscopy (SEM), rheology testing and compression testing. From SEM, it is observed that the 7.5/0.1% concentration has the largest pore size. Rheology testing reveals that all concentrations display a shear-thinning behaviour. However, a lower concentration of GG results in lower viscosity, which may compromise the printing resolution. Compression testing shows that the 7.5/0.5% concentration has the highest compressive modulus of 28.3 kPa. Printing in 2D and 3D was performed using the multi-nozzle extrusion-based bioprinter to fabricate the desired construct. By investigating the effects of pressure and feed rate on line width as well as on the stability and overall height of the printed construct, the parameters for printing the desired construct were optimized. From printing tests, it is concluded that the 7.5/0.5% concentration has the best printability to fabricate the desired construct. Through the experiments, the optimal pressures, feed rates, filament spacing, configuration and GelMA/GG concentration are obtained, which has allowed the successful printing of the desired construct. This desired construct that is printed can be used for further studies to investigate its effectiveness as a nerve scaffold for spinal cord regeneration.