Biofabrication of 3D constructs: Fabrication technologies and spider silk proteins as bioinks

Abstract

Despite significant investment in tissue engineering over the past 20 years, few tissue engineered products have made it to market. One of the reasons is the poor control over the 3D arrangement of the scaffold's components. Biofabrication is a new field of research that exploits 3D printing technologies with high spatial resolution for the simultaneous processing of cells and biomaterials into 3D constructs suitable for tissue engineering. Cell-encapsulating biomaterials used in 3D bioprinting are referred to as bioinks. This review consists of: (1) an introduction of biofabrication, (2) an introduction of 3D bioprinting, (3) the requirements of bioinks, (4) existing bioinks, and (5) a specific example of a recombinant spider silk bioink. The recombinant spider silk bioink will be used as an example because its unmodified hydrogel format fits the basic requirements of bioinks: to be printable and at the same time cytocompatible. The bioink exhibited both cytocompatible (self-assembly, high cell viability) and printable (injectable, shear-thinning, high shape fidelity) qualities. Although improvements can be made, it is clear from this system that, with the appropriate bioink, many of the existing faults in tissue-like structures produced by 3D bioprinting can be minimized.