Constructing a Sr2+-Substituted Surface Hydroxyapatite Hexagon-Like Microarray on 3D-Plotted Hydroxyapatite Scaffold to Regulate Osteogenic Differentiation.

Yingqi Wei,Yingjun Wang,Lijing Hao,Xuetao Shi,Huichang Gao

doi:10.3390/nano10091672

Abstract

Surface topography and chemical characteristics can regulate stem cell proliferation and differentiation, and decrease the bone-healing time. However, the synergetic function of the surface structure and chemical cues in bone-regeneration repair was rarely studied. Herein, a strontium ion (Sr2+)-substituted surface hydroxyapatite (HA) hexagon-like microarray was successfully constructed on 3D-plotted HA porous scaffold through hydrothermal reaction to generate topography and chemical dual cues. The crystal phase of the Sr2+-substituted surface microarray was HA, while the lattice constant of the Sr2+-substituted microarray increased with increasing Sr2+-substituted amount. Sr2+-substituted microarray could achieve the sustainable release of Sr2+, which could effectively promote osteogenic differentiation of human adipose-derived stem cells (ADSCs) even without osteogenic-induced media. Osteogenic characteristics were optimally enhanced using the higher Sr2+-substituted surface microarray (8Sr-HA). Sr2+-substituted microarray on the scaffold surface could future improve the osteogenic performance of HA porous scaffold. These results indicated that the Sr2+-substituted HA surface hexagon-like microarray on 3D-plotted HA scaffolds had promising biological performance for bone-regeneration repair scaffold.

Highlights

For large bone defects caused by severe fractures, tumor resection, or osteonecrosis, bone tissue itself cannot fully repair and regenerate [1,2]
The results showed that the adipose-derived stem cells (ADSCs) proliferated and spread well on HA scaffold surfaces with different Sr2+-substituted HA hexagon-like microarray, and spread over the entire scaffold surface after culture for 7 days, demonstrating that the HA scaffold with hexagon-like microarray surface
ADSCs could spontaneously adhere to the scaffold surface with the Sr2+-substituted and filopodia could be clearly observed, indicating that the cells were in a spreading state. These results showed that the HA scaffolds with the Sr2+-substituted microarray has good cell compatibility

Summary

Introduction

For large bone defects caused by severe fractures, tumor resection, or osteonecrosis, bone tissue itself cannot fully repair and regenerate [1,2]. Tissue engineering could effectively break through the barriers of existing treatment methods and improve bone tissue repair. During the repair of damaged bones, bone repair scaffold as carrier for repairing bone defects can provide effective mechanical support [3]. Scaffold serves as a bridge between natural tissue and seed cells, providing spatial structure and growth templates for cell adhesion, proliferation and differentiation in bone regeneration and repair with the potential to regulate cell activity and fate [4,5]. Material selection and structural design of scaffold are key considerations in the process of bone repair

Objectives

Results

Conclusion