A novel direct ink writing manufacturing system to 3D print highly concentrated silk fibroin

Abstract

Silk fibroin has demonstrated high biocompatibility in contact with the human tissue and in cell culture. As a result, it has been studied to develop very promising medical devices. The medical field has initiated a trend towards customization that will prevail in the recent future. That is why, 3D printed medical devices are gaining attention and becoming more relevant. This work attempts to unify silk fibroin with 3D printing. For this purpose, a high-concentration silk fibroin extrusion system has been designed. This system consists of a novel method to concentrate the fibroin to an optimal viscosity for direct ink writing. This could be accomplished due to the shear shinning property of the silk, after being expelled the viscosity keeps the shape of the silk in the place where it was deposited. Then, the system applies temperature to the silk to create a solid structure. A modular prototype has been created. It can print on any type of surface, flat or tubular. To evaluate the accuracy of the system on a flat printing bed, fluid flow rate and nozzle speed were evaluated in the fabrication of a mesh that simulated a flat cardiovascular stent. Images of the results were captured with a stereoscopic microscope, the dimensions of the result were calculated and compared with the chosen parameters. Thus, this work characterizes these features with the print resolution of the system. Finally, it opens a new paradigm for 3D printed medical devices based on silk fibroin.