3D Printing of a Biocompatible Double Network Elastomer with Digital Control of Mechanical Properties

The majority of 3D-printed biodegradable biomaterials are brittle, limiting their application to compliant tissues. Poly(glycerol sebacate) acrylate (PGSA) is a synthetic biocompatible elastomer and compatible with light-based 3D printing. In this article, digital-light-processing (DLP)-based 3D printing is employed to create a complex PGSA network structure. Nature-inspired double network (DN) structures consisting of interconnected segments with different mechanical properties are printed from the same material in a single shot. Such capability has not been demonstrated by any other fabrication techniques so far. The biocompatibility of PGSA is confirmed via cell-viability analysis. Furthermore, a finite-element analysis (FEA) model is used to predict the failure of the DN structure under uniaxial tension. FEA confirms that the DN structure absorbs 100% more energy before rupture by using the soft segments as sacrificial elements while the hard segments retain structural integrity. Using the FEA-informed design, a new DN structure is printed and tensile test results agree with the simulation. This article demonstrates how geometrically-optimized material design can be easily and rapidly constructed by DLP-based 3D printing, where well-defined patterns of different stiffnesses can be simultaneously formed using the same elastic biomaterial, and overall mechanical properties can be specifically optimized for different biomedical applications.