Engineering and Evaluation of 3D Printed Polymer Scaffolds for Bone Tissue Regeneration

Overview

The regeneration of bone defects caused by trauma, fracture, and disease is a significant clinical challenge for both military and civilian patients in the United States and around the world. Currently, the annual cost for bone fracture repair exceeds $19 billion and by 2025 annual fractures and cost is projected to increase by 50%. This cost is a heavy burden for the society. There are two main types of bone grafts used in bone fracture repair, namely autografts and allografts. These grafts provide both mechanical and structural support during bone healing. Autograft bone tissue is taken from the patient’s own healthy bone and then implanted into the fractured site. On the other hand, allograft is taken from cadaver, no viable cells exist. However, the harvest site of autograft is subjected to injure by the removal of the graft and patient undergoes donor site morbidity such as blood loss, infection risk, and scar formation. The main clinical drawback from the allograft is immunologic mismatch. The ideal scaffolds for bone tissue repair should provide biocompatibility, pore architecture, biodegradability, mechanical support, and cell attachment sites. Conventionally fabricated polymer scaffolds are unable to make an ideal scaffolds for bone tissue repair. In this study, melted polycaprolactone (PCL) was used as a bioink to print the 3D porous scaffolds with computer controlled layer-by-layer process using extrusion printing. PCL is a thermoplastic polyester and melts at 58-60ºC. PCL degrades at a slow rate within 1.5-2 years and is non-toxic. In this study, new 3D printing technology was used to print porous PCL scaffolds. The hypothesis of this study is to engineer 3D printed porous PCL scaffolds that can mimic porosity, pore morphology, mechanical properties, biocompatibility and cell attachment similar to human bone. Three different types of PCL scaffolds with pore sizes 200 μm, 400 μm, and 800 μm were designed using a computer software. These scaffolds were characterized for percent porosity, pore architecture, morphology, mechanical properties, and evaluated for biocompatibility and cell attachment with murine osteoblasts. The percent porosity of these scaffolds (n=7) has significantly increased from 13 to 62 (p<0.001) with the increase of pore sizes. The average compressive modulus of scaffolds (n=7) significantly decreased with the increase of pore sizes (p<0.001). The averaged compressive modulus of scaffolds with 200 μm, 400 μm, and 800 μm pores is 83, 62, and 47 MPa, respectively. These scaffolds have shown non-cytotoxicity allowing pre-osteoblasts to attach and proliferate as determined by cell culture studies at day 4 and day 7. These scaffolds have shown the reproducibility, biocompatibility, pore interconnectivity, porosity similar to bone, and compressive modulus similar to bone and provides attachment sites for cells. Therefore, these PCL scaffolds can be potentially use to regenerate or repair bone defects caused by various reasons.

Competition history

AJAS 2018 Category not listed

Related projects

ISEF · 2017