Three dimensional printed macroporous polylactic acid/hydroxyapatite composite scaffolds for promoting bone formation in a critical-size rat calvarial defect model

Haifeng Zhang,Xiyuan Mao,Zijing Du,Wenbo Jiang,Xiuguo Han,Danyang Zhao,Dong Han,Qingfeng Li

doi:10.1080/14686996.2016.1145532

Abstract

We have explored the applicability of printed scaffold by comparing osteogenic ability and biodegradation property of three resorbable biomaterials. A polylactic acid/hydroxyapatite (PLA/HA) composite with a pore size of 500 μm and 60% porosity was fabricated by three-dimensional printing. Three-dimensional printed PLA/HA, β-tricalcium phosphate (β-TCP) and partially demineralized bone matrix (DBM) seeded with bone marrow stromal cells (BMSCs) were evaluated by cell adhesion, proliferation, alkaline phosphatase activity and osteogenic gene expression of osteopontin (OPN) and collagen type I (COL-1). Moreover, the biocompatibility, bone repairing capacity and degradation in three different bone substitute materials were estimated using a critical-size rat calvarial defect model in vivo. The defects were evaluated by micro-computed tomography and histological analysis at four and eight weeks after surgery, respectively. The results showed that each of the studied scaffolds had its own specific merits and drawbacks. Three-dimensional printed PLA/HA scaffolds possessed good biocompatibility and stimulated BMSC cell proliferation and differentiation to osteogenic cells. The outcomes in vivo revealed that 3D printed PLA/HA scaffolds had good osteogenic capability and biodegradation activity with no difference in inflammation reaction. Therefore, 3D printed PLA/HA scaffolds have potential applications in bone tissue engineering and may be used as graft substitutes in reconstructive surgery.

Highlights

Regeneration of massive bone defects caused by trauma, infection, tumor resection and congenital defects is a major treatment challenge in plastic and reconstructive surgery as well as orthopedic surgery
The scaffolds of 3D printed polylactic acid/hydroxyapatite (PLA/HA) (85 wt%: 15% wt%) had relatively compact porosity with an average value of 60%; the mean pore size was 500 μm, as expected. β-tricalcium phosphate (β-TCP) ceramic scaffolds had a mean porosity of 60% and a pore diameter of 50–600 μm
The results showed that 3DP Polylactic acid (PLA)/HA scaffolds stimulated the proliferation, Alkaline phosphatase (ALP) activity and osteogenesis-related gene expression of bone marrow stromal cells (BMSCs)

Summary

Introduction

Regeneration of massive bone defects caused by trauma, infection, tumor resection and congenital defects is a major treatment challenge in plastic and reconstructive surgery as well as orthopedic surgery. Allografts and xenografts are used for repairing osseous defects with drawbacks in disease transmission and immune rejection [3]. Due to these shortcomings, the researches for different types of bone graft substitute have intensified for decades for filling defects, even when the bone mass is inadequate. The ideal bone substitute materials should fill multiple roles including the ability to deliver cells, support differentiation of regenerative cells and fabricate irregular shapes, biocompatibility, osteoconductivity, osteoinductivity, controlled biodegradability and the growth of new bone into the augmented area [7,8,9]

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