Polymer-ceramic composites for fused deposition modeling of biomimetic bone scaffolds

Abstract

Current surgical treatments for segmental bone loss do not reliably result in healing, typically necessitate multiple surgeries, and may result in amputation. Although we have demonstrated that polybutylene terephthalate (PBT) scaffolds can regenerate large critical size bone defects, the material is non-resorbable and may lead to problems including acting as a nidus for infection. New strategies have emerged that use resorbable polymers, ceramics, and composite materials to produce patient specific scaffolds that stimulate rapid bone formation without retention of foreign material. This work describes the production of a composite polymer ceramic material composed of polylactic acid (PLA) and tricalcium phosphate (TCP) that can be used with additive manufacturing techniques to rapidly produce scaffolds with custom geometries. The technique we describe can be used to produce composite materials with a ratio of up to 50-50 PLA-TCP that is suitable for fused deposition modeling and does not necessitate the use of solvents. In this study the properties of PBT, PLA, 75-25 PLA-TCP, and 50-50 PLA-TCP materials are compared. PLA and PLA-TCP materials had a higher compressive elastic modulus compared to PBT, while composite PLA-TCP materials had a higher tensile elastic modulus compared to PLA and PBT. Cell culture experiments demonstrated that all materials were non-toxic to cells. Optimal printing parameters are provided for using pure polymer and composite materials for fused deposition modeling. The results of this study demonstrate that resorbable polymer ceramic materials with a high ceramic composition can be produced for additive manufacturing without necessitating solvents.