Poly(propylene fumarate) stars, using architecture to reduce the viscosity of 3D printable resins

Abstract

Additive manufacturing is changing tissue engineering by offering pathways to otherwise unattainable, highly complex scaffold morphologies. Linear poly(propylene fumarate) (PPF) oligomers have demonstrated remarkable properties for 3D printing of porous gyroid scaffolds using continuous digital light processing (cDLP). Nevertheless, the narrow molar mass range with suitable viscosity properties for printing severely limits the printing speed, the breadth of mechanical properties, and the resorption window of the scaffolds. To overcome this constraint, we report the divergent synthesis of four-arm PPF using the sugar-based alcohol meso-erythritol as an initiator. Using a combination of ¹H NMR spectroscopy, size exclusion chromatography (SEC), MALDI-ToF spectrometry and viscosity measurements, the well-defined star-shape architecture was confirmed. Subsequently, printable resins based on star PPF were prepared and showed complex viscosity decreasing as the total increases, allowing rapid printing of PPF with nearly eight times larger than the largest linear PPF oligomer printed previously.