Direct Writing Of Silk Fibroin For Use In Three Dimensional Culture Models Of Mammary Gland Tissue

Abstract

While the emergence of additive manufacturing, or “3D printing”, as an affordable and readily available new technology seems to dominate technical media outlets and news stories for its promise in manufacturing plastic shapes and forms, the process has particularly interesting applications with forms and materials in the biomedical field as well. Whereas easily-editable forms and shapes have obvious uses at the macro-scale for applications like joint and bone replacements, the ability of additive manufacturing to create forms with micrometer-scale resolution will allow for a deeper understanding of how tissues form and differentiate. Here, we examined best practices for additive manufacturing of Bombyx mori silk fibroin, a protein with previously demonstrated benefit in applications of tissue engineering and culture models. We found that silk fibroin could be used as a substratum onto which EpH4 mammary cells could attach and proliferate, and that this effect was greatly improved with incorporation of fetal bovine serum (FBS), as silk fibroin does not otherwise offer many surface molecules to which mammary cells can attach. Finally, we applied 3D printing of silk fibroin to create fibers for use in three dimensional collagen culture models, in order to investigate mechanisms through which cancerous mammary cells can metastasize.