SILK-BASED MATERIALS TO CREATE HIGH RESOLUTION THREE-DIMENSIONAL STRUCTURES USING ELECTROHYDRODYNAMIC PRINTING

Abstract

Mimicking the complex hierarchical structure of the extracellular matrix (ECM) has always been a major goal in tissue engineering (TE) approaches [1] [2]. Despite the great advances in biomaterial processing technologies, the main limitation concerns the resolution of the fibers, which hampers the reproduction of ECM. Here, we combine Silk Fibroin (SF) [5], a highly potent biomaterial that intrinsically has the characteristics of making fibrous structures, with Electrohydrodynamic printing, an innovative 3D printing technique that allows patterning at micro and sub micro scale. To fabricate these complex structures, Electrohydrodynamic printing applies a voltage between the needle and the collector screen to charge the polymer solution, with a consequent thinning of the fibers, making it possible to reach optimal resolutions for recreating the hierarchical and fibrillar structure of ECM [3] [4]. We have studied SF in its chemical structure to allow a better understanding of the structural and mechanical behaviour of the material before and after printing. We have demonstrated the printability of SF with Electrohydrodynamic printing and, just by tuning the rheological properties, it is possible to obtain straight fibers with a resolution of 10‐20 mm. We have also demonstrated that these fibers can be physically crosslinked inducing the formation of b‐sheets structure in the protein chain; after crosslinking the fibers are stable and don't dissolve in water. SF is therefore proving to be an optimal material for this application and is gaining strong interest in soft tissue engineering.