Designing bioactive porous titanium interfaces to balance mechanical properties and in vitro cells behavior towards increased osseointegration
Designing bioactive porous titanium interfaces to balance mechanical properties and in vitro cells behavior towards increased osseointegration
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DOI：
10.1016/j.surfcoat.2019.03.001
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发表时间：
2019-06-25
影响因子：
5.4
通讯作者：
Torres, Yadir
中科院分区：
文献类型：
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作者：
Civantos, Ana;Dominguez, Cristina;Torres, Yadir
钛种植体的失败主要与应力遮挡现象和细胞与宿主骨组织的相互作用差有关。开发具有生物活性和仿生性的钛支架用于骨再生仍然是一个挑战，这就需要设计具有增强骨整合的钛种植体。在此背景下，采用传统的粉末冶金方法制备了全致密、致密腐蚀、多孔钛和多孔钛4种类型的钛样品。采用间隔器技术，以碳酸氢铵颗粒为间隔物，制备了三种不同粒径范围(100~200微米、250~355微米和355~500微米)的多孔样品。通过在不同时间(125时和62时S)对衬底进行化学腐蚀，并从微观结构、形貌和力学角度对其进行了表征。蚀刻表面显示出优先位于气孔内的额外粗糙度。体外实验表明，所有底物都是生物相容的(细胞存活率的80%)，证实了预母细胞的细胞黏附。同样，成骨细胞在第4天表现出相似的细胞增殖率，但在第7天观察到完全致密和致密蚀刻表面的细胞代谢活性更高。相反，与对照表面(致密和致密腐蚀)相比，多孔性和多孔性蚀刻样品中碱性磷酸酶的表达显著增加，注意到合适的表面修饰参数(孔隙率和粗糙度)以改善细胞分化。此外，多孔钛基质的孔洞和粗糙表面的存在显著减少了巨噬细胞的激活，减少了M1表型极化以及M1细胞标志的表达。因此，成功地对多孔钛支架进行了表面改性，以减少应力遮挡现象，促进骨整合，达到生物力学和生物功能的平衡。
Titanium implant failures are mainly related to stress shielding phenomenon and the poor cell interaction with host bone tissue. The development of bioactive and biomimetic Ti scaffolds for bone regeneration remains a challenge which needs the design of Ti implants with enhanced osseointegration. In this context, 4 types of titanium samples were fabricated using conventional powder metallurgy, fully dense, dense etched, porous Ti, and porous etched Ti. Porous samples were manufactured by space holder technique, using ammonium bicarbonate particles as spacer in three different ranges of particle size (100-200 mu m, 250-355 mu m and 355-500 mu m). Substrates were chemically etched by immersion in fluorhydric acid at different times (125 and 625 s) and subsequently, were characterized from a micro-structural, topographical and mechanical point of view. Etched surfaces showed an additional roughness preferentially located inside pores. In vitro tests showed that all substrates were biocompatible (80% of cell viability), confirming cell adhesion of premioblastic cells. Similarly, osteoblast showed similar cell proliferation rates at 4 days, however, higher cell metabolic activity was observed in fully dense and dense etched surfaces at 7 days. In contrast, a significant increase of alkaline phosphatase enzyme expression was observed in porous and porous etched samples compared to control surfaces (dense and dense etched), noticing the suitable surface modification parameters (porosity and roughness) to improve cell differentiation. Furthermore, the presence of pores and rough surfaces of porous Ti substrates remarkably decreased macrophage activation reducing the M1 phenotype polarization as well M1 cell marker expression. Thus, a successful surface modification of porous Ti scaffolds has been performed towards a reduction on stress shielding phenomenon and enhancement of bone osseointegration, achieving a biomechanical and biofunctional equilibrium.