Development and analysis of modular-based bioprinter for three-dimensional (3D) print of hydrogel

• Main Author: Abert Achilles Nunong, Abernice Ann
• Format: Thesis
• Language: English; English
• Published: 2024
• Online Access: http://eprints.utem.edu.my/id/eprint/28624/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=124336

Bioprinting is an emerging technology to produce biologically adaptive tissues and organs particularly useful in clinical treatment, requiring the replacement of body parts. The alternative to producing biologically adaptive material has been studied using additive manufacturing (AM) technology due to its ability to create complex geometry. However, building soft biological tissues using a three-dimensional (3D) print technology has been significant challenge in bioprinting. Furthermore, the accessibility and customisation of the existing bioprinter has its own limitation. Moreover, the existing bioprinter experiences vibration issue and volume of syringe which impacts on printing quality. Therefore, this study aims to develop the Modular-based Syringe Extruder (MSE) on the 3D printer technology to enable customised 3D printing of biomaterial. A sodium alginate with 2% (w/v) represents a medium viscosity, ideal for hydrogel print. The printing variable will be investigated for seven printing parameters, which are nozzle shape, nozzle size, layer height, print speed, infill percentage, flow rate and retraction effect. Furthermore, the optimisation of the printing parameters would have been performed using the L8(27) orthogonal array. The quality of the printed would have been measured based on the scoring system. Based on Taguchi method, the data collected from the experiment was analyzed using concept of signal-to-noise ratio (SNR). Response data reveals that the print speed and retraction effect is the most significant factor that effects the printing quality. On the other hand, response graph shows that conical nozzle shape, 18G nozzle size, 0.8 mm layer height, 4 mm/s print speed, 15% infill percentage, 100% flow rate and no retraction effect are the optimal printing parameter in order to print high quality of printed structure. Printing soft biomaterials such as sodium alginate has been a major challenge due to their susceptibility to gravitational collapse. To overcome the issue, a Freeform Reversible Embedding of Suspended Hydrogels (FRESH) method was developed, providing solution by holding the sodium alginate in gelatin slurry support bath during printing. This method polymerizes the biomaterial for crosslinking, resulting in a well-structured scaffold build-up. The experiment involved printing four different structures, including grid square, circle, zigzag and blood vein profile, all of which were successfully printed five layers of 3D printed alginate scaffold. Compression testing and microstructure analysis were conducted to evaluate strength and porosity of the hydrogel. It was found that the stress value was 0.0150.003 MPa when the hydrogel was compressed up to 70% before failure. Furthermore, microstructure analysis of the scaffold revealed a high porosity (25-255 m), which creates an ideal environment for cell attachment and migration. Overall, this research contributes valuable knowledge to the field of bioprinting and its potential applications in clinical treatments, particularly in the context of replacing degenerated body parts.