Silk spinning-inspired 3D printing

Silk spinning of spiders and silkworms is a natural version of extrusion-based 3D printing, from protein-constituted secretion to 3D structures like orb webs and cocoons. Also, silk spinning is characterized by ambient and aqueous processing conditions and superior mechanical performance, exhibiting a molecular mechanism fundamentally different from conventional polymer manufacturing (involving heating and organic solvents). Thus, silk spinning represents a source of inspiration for sustainable additive manufacturing of polymers. Proteins are a major building block of living systems, implying the advantages of proteinaceous materials compared with most synthetic polymers. We have preliminarily exploited the native solvent environment of the spinning gland and developed a de novo salt bath for 3D printing with monolithic silk fibroin inks (Link). This work indicates the numerous opportunities for exploiting the underlying mechanisms of silk spinning, such as salt-induced hierarchical molecule assembly, and paves the way for additive manufacturing of proteinaceous biomedical devices.