Fabrication of hybrid scaffolds by polymer deposition system and its in-vivo evaluation with a rat tibial defect model

The purpose of this study was to investigate the bone regeneration ability of a polycaprolactone (PCL) tube scaffold fabricated by using a polymer deposition system with G-code and to evaluate the biocompatibility of bone graft material with Bio-C (HA (30%)/TCP (70%)), carboxymethyl cellulose (CMC), and bone morphogenetic protein-2(BMP-2). The fabrication of a rapid prototyping-based PCL tube scaffold requires a combination of several devices, including a heater, pressure dispenser, and motion controller, etc. This system can process polymer with high precision by a 200-μm nozzle. We used scanning electron microscopy to observe the surface of fabricated scaffold. Three groups considered in this study were PCL tube scaffold (Group A), BMP-2(0.1 mg)/Bio-C/CMC/PCL scaffold (Group B), and BMP-2(0.5 mg)/Bio-C/CMC/PCL scaffold (Group C). The functional recovery and bone regeneration potential were estimated by performing an in-vivo animal experiment with a white rat model. Then, the effect of the scaffold on tibial defects in rats was examined by observing an X-ray image at 4 or 8 weeks and by carrying out histological analysis. In this study, scaffolds fabricated by using the PDS (polymer deposition system), had a diameter of 4.0 mm and a height of 8.0 mm. Moreover, we confirmed that group C exhibited better biomedical characteristics for bone formation than the other scaffolds. The evaluation of in-vivo experimental results suggested that the co-fabrication of the PCL tube scaffold with group C resulted in sustained bone regeneration, which in turn improved the biocompatibility of the bone graft material.