The Effect of Strontium-Substituted Hydroxyapatite Nanofibrous Matrix on Osteoblast Proliferation and Differentiation.

Shiao-Wen Tsai,Yu-Wei Hsu,Whei-Lin Pan,Fu-Yin Hsu

doi:10.3390/membranes11080624

Abstract

Natural bone tissue consists primarily of bioapatite and collagen. Synthetic hydroxyapatite (HA) possesses good biocompatibility, bioactivity, and osteoconductivity due to its chemical and biological similarity to bioapatite. Hence, HA has been widely used as a bone graft, cell carrier and drug/gene delivery carrier. Moreover, strontium-substituted hydroxyapatite (SrHA) can enhance osteogenic differentiation and inhibit adipogenic differentiation of mesenchymal stem cells. Hence, SrHA has the potential to be used as a bone graft for bone regeneration. It is widely accepted that cell adhesion and most cellular activities are sensitive to the topography and molecular composition of the matrix. Electrospun polymer or polymer-bioceramic composite nanofibers have been demonstrated to enhance osteoblast differentiation. However, to date, no studies have investigated the effect of nanofibrous bioceramic matrices on osteoblasts. In this study, hydroxyapatite nanofiber (HANF) and strontium-substituted hydroxyapatite nanofiber (SrHANF) matrices were fabricated by electrospinning. The effect of the HANF components on MG63 osteoblast-like cells was evaluated by cell morphology, proliferation, alkaline phosphatase activity (ALP) and gene expression levels of RUNX2, COLI, OCN and BSP. The results showed that MG63 osteoblast-like cells exhibited higher ALP and gene expression levels of RUNX2, COLI, BSP and OCN on the SrHANF matrix than the HANF matrix. Hence, SrHANFs could enhance the differentiation of MG63 osteoblast-like cells.

Highlights

The development of multifunctional bioactive materials for repairing large bone defects caused by trauma, infection, skeletal abnormalities or tumor resection is an important issue [1,2,3]
The RUNX2 gene expression of MG63 cells was significantly higher in the strontium-substituted hydroxyapatite nanofibers (SrHANFs) and hydroxyapatite nanofiber (HANF) matrices than in the control group
Osteoblast-like MG63 cells grown on SrHANF matrix showed higher levels of collagen type I (COLI), RUNX2, bone sialoprotein (BSP), and OCN mRNA and higher Alkaline Phosphatase (ALP) activity than those grown on HANF matrix

Summary

Introduction

The development of multifunctional bioactive materials for repairing large bone defects caused by trauma, infection, skeletal abnormalities or tumor resection is an important issue [1,2,3]. Bone defects caused by infected nonunion make it difficult to eradicate pathogens. Chronic bone infection usually needs long-term systemic antibiotic treatment after surgical debridement. Zhang et al [5] pointed out that Sr-substituted hydroxyapatite (SrHA) obtained by the partial substitution of Ca2+ by Sr2+ has higher solubility than pure HA. Ni et al [7] found that HA ceramics with 5 and 10 mol% Sr substitution enhanced osteoblastic cell differentiation and mineralization. Sr ions may promote the differentiation of osteoblast cells by activating downstream Cbfa1 [8]. Ravi et al [11] found that SrHA exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus

Objectives

Methods

Findings

Conclusion