3D bioprinting of alginate and calcium phosphate cement (CPC) scaffolds for drug delivery and tissue regeneration

3D bioprinting is manufactural biotechnology which was used to create a drug delivery system with advanced functions and personalised tissue regeneration. In this study, 3D scaffolds were bio-printed using different bio-ink formulations including pure alginate, alginate-methylcellulose (MC), polylactic acid (PLA) with polyethylene glycol (PEG), and calcium phosphate cement (CPC). The properties of biomaterials were analysed by viscometer and texture analyser. Confocal microscopy, scanning electron microscopy (SEM) and X-Ray powder diffraction (XRD) were applied for surface evaluation of the samples. In vitro cell studies were used for testing cell viability and anti-cancer function of 3D bio-printed scaffolds. The mathematical models between the concentration of pure alginate (C) and viscosity (V) in different pH have been explored, which were V=0.0019C4.9061 at pH=1.2, V=73.097e0.1788C at pH=6.6 and V=0.4059C2.7997 at pH=7.2 respectively. Among all the 3D bio-printed alginate-MC scaffolds, the scaffold made from alginate-MC with a ratio of 1:1 showed a positive effect on cancer cells and inhibited the growth of cancer cells within 4 days, indicating its effective function in anti-cancer drug delivery system. Besides, 3D bio-printed PLA/PEG scaffolds loaded with growth factor erythropoietin (EPO) were proved to be valid for assisting cell repair. And 5-Fluorouracil (5-FU) coated CPC scaffolds showed effective controlled-release drug delivery and anti-cancer function within 4 days. Those 3D bio-printed novel scaffolds illustrated their outstanding potential for future clinical use in both drug delivery and tissue engineering field. Finally, the change of cell behaviour was observed visually by culturing scaffolds with 1BR, HEK293T-GFP and U2OS-GFP cell lines for 28 days. The quantitative analysis showed that the size and structure of scaffolds were two important factors affecting the behaviour of cells and 3D CPC scaffolds in size S (diameter ~9.4mm) is the most suitable one culturing with 1BR cells. The whole thesis explored 3D bio-printed scaffolds in three perspectives, formulations, scaffolds and in vitro functions, which contributed to understanding bio-inks/scaffolds’ physical-chemical properties, clinical functions and cell-scaffold interactions