Design and fabrication of biodegradable bone tissue scaffolds based on the nuclear pasta theory

Abstract

Globally, around 2.2 million bone graft procedures are performed annually, with costs reaching approximately $664 million as of 2021. The number of surgeries to repair bone defects is projected to increase by about 13 % each year. However, traditional bone grafts often carry risks such as donor site morbidity and limited availability, driving the need for innovative solutions. This study explores the fabrication of biodegradable bone tissue scaffolds inspired by the nuclear pasta theory using extrusion-based Fused Deposition Modeling (FDM). The nuclear pasta theory, which describes complex geometrical formations within neutron stars, serves as a novel source of inspiration for designing scaffolds with enhanced mechanical properties and optimized porosity. Two bio-based, biodegradable polymers, Luminy LX175 and ecoPLAS, were used to fabricate scaffolds via an in-house filament extrusion process utilizing the Filabot EX6 system. The extrusion parameters were optimized to achieve a consistent filament diameter of 1.75 mm suitable for 3D printing on a Creality K1C printer. Seven scaffold designs were developed, including five based on Triply Periodic Minimal Surfaces (TPMS) and two inspired by nuclear pasta configurations, namely “lasagna” and a hybrid “lasagna-spaghetti” structure. The scaffolds were evaluated for their mechanical properties using uniaxial compression testing. Results showed that TPMS-inspired designs generally achieved a favorable balance between porosity and mechanical strength, while the nuclear pasta-inspired designs exhibited unique anisotropic and isotropic compression characteristics. The study concluded that nuclear pasta-inspired scaffold architectures exhibit unique mechanical properties and porosity characteristics, emphasizing their potential for future optimization in bone tissue engineering applications. Additionally, these structures can be further reinforced through material modifications or hybrid scaffold designs to enhance their load-bearing capabilities. This work demonstrates the potential of using bio-inspired designs in conjunction with sustainable, biodegradable materials for bone tissue engineering. Future research will focus on optimizing co-extrusion techniques and exploring composite materials to further enhance scaffold properties for clinical applications.