Department of Materials, Imperial College London, London SW7 2AZ, UK.
Acta Biomater. 2010 Dec;6(12):4596-604. doi: 10.1016/j.actbio.2010.06.027. Epub 2010 Jun 30.
We present a novel route for producing a new class of titanium foams for use in biomedical implant applications. These foams are hierarchically porous, with both the traditional large (>300μm) highly interconnected pores and, uniquely, wall struts also containing micron scale (0.5-5μm) interconnected porosities. The fabrication method consists of first producing a porous oxide precursor via a gel casting method, followed by electrochemical reduction to produce a metallic foam. This method offers the unique ability to tailor the porosity at several scales independently, unlike traditional space-holder techniques. Reducing the pressure during foam setting increased the macro-pore size. The intra-strut pore size (and percentage) can be controlled independently of macro-pore size by altering the ceramic loading and sintering temperature during precursor production. Typical properties for an 80% porous Ti foam were a modulus of ∼1GPa, a yield strength of 8MPa and a permeability of 350 Darcies, all of which are in the range required for biomedical implant applications. We also demonstrate that the micron scale intra-strut porosities can be exploited to allow infiltration of bioactive materials using a novel bioactive silica-polymer composite, resulting in a metal-bioactive silica-polymer composite.
我们提出了一种生产用于生物医学植入物应用的新型钛泡沫的新途径。这些泡沫具有分级多孔结构，既有传统的大尺寸（>300μm）高度连通的孔隙，又有独特的壁支柱，其中还包含微米级（0.5-5μm）连通的孔隙。该制造方法包括首先通过凝胶铸造法生产多孔氧化物前体，然后通过电化学还原生产金属泡沫。与传统的空间保持技术不同，这种方法提供了在几个尺度上独立定制孔隙率的独特能力。在泡沫设置过程中降低压力会增加大孔尺寸。通过改变陶瓷负载和前驱体制备过程中的烧结温度，可以独立于大孔尺寸控制内支柱的孔径（和百分比）。80%多孔 Ti 泡沫的典型性能为模量约为 1GPa、屈服强度为 8MPa 和渗透率为 350 达西，所有这些都在生物医学植入物应用所需的范围内。我们还证明，微米级的内支柱孔隙可以被利用来允许使用新型生物活性硅-聚合物复合材料进行生物活性材料的渗透，从而形成金属-生物活性硅-聚合物复合材料。
