Abstract
Additive manufacturing has transformed and disrupted the manufacturing economy radically and is currently driving the fourth industrial revolution. Scientists and engineers have joined the bandwagon to exploit 3D printing immensely to achieve better outcomes in areas such as microfabrication to engineer biomimetic tissues. In particular, 3D printing using commercially available FDM 3D printers have potentiated the fabrication of scaffolds and sacrificial molds to recreate the complex architecture that can coax human tissues to grow on the bench. Sacrificial molds can be designed digitally to act as replicas to the human vasculature. The molds, when embedded in a hydrogel, could recreate these replicas (microchannel) after they were removed. Despite efforts to use the sacrificial molding method to create these replicas of the vasculature, progress is still hampered by the lack of methods to print complex geometry and the choice of robust material for use in the water-rich hydrogel. Herein, we demonstrate three techniques to overcome and print complex geometry with the FDM 3D printer and invented one material that is water resilient in removal in water. Firstly, we designed and printed delicate features on the sacrificial mold, which used to fabricate a micromixer within the microchannel. We created modular pieces of sacrificial mold, which was preassembled into 3D to fabricate microchannel with truly 3D interconnects. Secondly, we use dual extrusion to print two sacrificial materials that were sequentially removed to fabricate microchannels with overhang, helical and pyramidal geometries. Thirdly, we optimized and the printing parameters on the FDM 3D printers to print very long and thin bridges to fabricate microchannels with a circular, symmetrical cross-section. The bridges have high autonomy and can be printed in multiple configurations. Fourthly, we invented a novel material that is water resilient and water removal. The use of the material has enabled us to surpass the resolution of microchannel fabricated in hydrogels. Also, the novel material was used to fabricate a vasculature capable of effecting a pulsatile blood flow and create vascular disease models. The thesis has contributed a total of eight peer-reviewed journal publications, three conference papers, sixteen conference talk or posters, two best poster paper awards, and one technology disclosure was filed.