Introduction

It is urgently needed to develop composite bone scaffold with excellent mechanical properties and bioactivity in bone tissue engineering. Combining graphene oxide (GO) and hydroxyapatite (HAP) for the reinforcement of biopolymer bone scaffold has emerged as a promising strategy. However, the dispersion of GO and HAP remains to be a big challenge.

Objectives

In this present work, the mechanical properties of GO and the bioactivity of and HAP were combined respectively via in situ synthesis for reinforcing biopolymer bone scaffold.

Methods

GO nanosheets were employed to in situ synthesize GO-HAP nanocomposite via hydrothermal reaction, in which their abundant oxygen-containing groups served as anchor sites for the chelation of Ca²⁺ and then Ca²⁺ absorbed HPO₄^2- via electrovalent bonding to form homogeneously dispersed HAP nanorods. Thereby, the GO-HAP nanocomposite was blended with biopolymer poly-L-lactic acid (PLLA) for fabricating biopolymer scaffold by selective laser sintering (SLS).

Results

GO nanosheets were uniformly decorated with HAP nanorods, which were about 60 nm in length and 5 nm in diameter. The compressive strength and modulus of PLLA/12%GO-HAP were significantly increased by 53.71% and 98.80% compared to the pure PLLA scaffold, respectively, explained on the base of pull out, crack bridging, deflection and pinning mechanisms. Meanwhile, the mineralization experiments indicated the PLLA/GO-HAP scaffold displayed good bioactivity by inducing the formation of apatite layer. Besides, cell culturing experiments demonstrated the favorable cytocompatibility of scaffold by promoting cell adhesion and proliferation.

Conclusions

The present findings show the potential of PLLA/GO-HAP composite scaffold via in situ synthesis in bone tissue engineering.

中文翻译：

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氧化石墨烯纳米片上羟基磷灰石纳米棒的原位合成及其在生物聚合物支架中的增强

介绍

骨组织工程迫切需要开发具有优异力学性能和生物活性的复合骨支架。结合氧化石墨烯（GO）和羟基磷灰石（HAP）来增强生物聚合物骨支架已成为一种有前途的策略。然而，GO和HAP的分散仍然是一个巨大的挑战。

目标

在目前的工作中，GO的机械性能和HAP的生物活性分别通过原位合成结合起来，用于增强生物聚合物骨支架。

方法

采用GO纳米片通过水热反应原位合成GO-HAP纳米复合材料，其中丰富的含氧基团作为Ca ²⁺螯合的锚定位点，然后Ca ²⁺通过电价键合吸收HPO ₄ ^2-形成均匀分散的HAP纳米棒。因此，将GO-HAP纳米复合材料与生物聚合物聚L-乳酸（PLLA）混合，通过选择性激光烧结（SLS）制备生物聚合物支架。

结果

GO纳米片上均匀地装饰有HAP纳米棒，其长度约为60 nm，直径约为5 nm。与纯 PLLA 支架相比，PLLA/12%GO-HAP 的抗压强度和模量分别显着增加了 53.71% 和 98.80%，这基于拔出、裂纹桥接、偏转和钉扎机制进行了解释。同时，矿化实验表明PLLA/GO-HAP支架通过诱导磷灰石层的形成而表现出良好的生物活性。此外，细胞培养实验证明了支架通过促进细胞粘附和增殖而具有良好的细胞相容性。

结论

目前的研究结果显示了 PLLA/GO-HAP 复合支架通过原位合成在骨组织工程中的潜力。