3D printing of hydrogels for biofabrication

Recently, hydrogels have been utilized as important biomaterials for 3D printing of three dimensional scaffolds for tissue engineering. The key factor for 3D printing is to select a hydrogel with a good 3D printability. Therefore, study on selecting a hydrogel with a good 3D printability is necessary. However, the printability of hydrogels is seldom addressed. Furthermore, there is a lack of study on 3D printing of using two hydrogels containing different charges. Thus, the study of applying two hydrogels carrying different charges to print them alternatively is vital. In this project, based on the method of semi-quantification of printability, the 3D printability was quantified. Instead of using one hydrogel for 3D printing, two hydrogels with different charges were printed alternatively. Four hydrogels, alginate, xanthan gum, gelatin and chitosan, were prepared in various concentrations and maintained under the same environmental conditions. The concentration of each hydrogel with the best 3D printability was selected for the final 3D printing process. The results of this study showed that when using two hydrogels with positive and negative charges to print alternatively, the ionic bonding improved the stability and performance of the scaffold structure as compared to the use of a hydrogel with positive or negative charges alone. The optimal layers which could be printed with a combination of 6wt% xanthan gum and 5wt% gelatin solutions were 50.Bachelor of Engineering (Mechanical Engineering