John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, University College London, Royal National Orthopaedic Hospital, Stanmore HA7 4LP, United Kingdom. Regenerative Biomaterials Group, RAFT Institute of Plastic Surgery, Mount Vernon Hospital, Northwood HA6 2RN, United Kingdom.
Biomed Mater. 2017 Nov 22;13(1):015008. doi: 10.1088/1748-605X/aa87e6.
Titanium and its alloys or tantalum (Ta) are materials used in orthopaedic and dental implants due to their excellent mechanical properties and biocompatibility. However, their bioactivity and osteoconductivity is low. With a view to improving the bioactivity of these materials we hypothesised that the surface of Ta and TiAl6V4 can be functionalised with biomimetic, amorphous nano-sized calcium phosphate (CaP) apatite-like deposits, instead of creating uniform coatings, which can lead to flaking, delamination and poor adherence. We used Ta and TiAl6V4 metal discs with smooth and rough surfaces. Amorphous CaP apatite-like particles were deposited on the different surfaces by a biomimetic rapid two-step soaking method using concentrated simulated body fluid (SBF) solutions without a pre-treatment of the metal surfaces to induce CaP deposition. Immersion times in the second SBF solution of 48 and 18 h for Ta and TiAl6V4 respectively produced CaP deposits composed of amorphous globular nano-sized particles that also contained Mg, C and O. Longer immersion times produced more uniform coatings as well as an undesired calcite mineral phase. Prediction of in vivo behaviour by immersion in regular SBF showed that the obtained CaP deposits would act as a catalyst to rapidly form a Ca deficient CaP layer that also incorporates Mg. The amorphous CaP apatite-like deposits promoted initial attachment, proliferation and osteogenic differentiation of bone marrow derived mesenchymal stem cells. Finally, we used our method to functionalise 3D porous structures of titanium alloy made by selective laser sintering. Our study uses a novel and cost-effective approach to functionalise clinically relevant metal surfaces in order to increase the bioactivity of these materials, which could improve their clinical performance.
钛及其合金或钽（Ta）由于其优异的机械性能和生物相容性而被用于骨科和牙科植入物。然而，它们的生物活性和骨传导性较低。为了提高这些材料的生物活性，我们假设可以用仿生的、非晶纳米级磷酸钙（CaP）磷灰石样沉积物来对 Ta 和 TiAl6V4 的表面进行功能化，而不是制造均匀的涂层，因为那样可能会导致剥落、分层和不良附着。我们使用了具有光滑和粗糙表面的 Ta 和 TiAl6V4 金属盘。通过使用浓缩模拟体液（SBF）溶液进行仿生两步快速浸泡方法，在不预先处理金属表面的情况下诱导 CaP 沉积，在不同表面上沉积了非晶 CaP 磷灰石样颗粒。Ta 和 TiAl6V4 分别在第二 SBF 溶液中浸泡 48 和 18 小时，产生了由非晶球形纳米颗粒组成的 CaP 沉积物，其中还含有 Mg、C 和 O。更长的浸泡时间会产生更均匀的涂层以及不希望的方解石矿物相。通过在常规 SBF 中浸泡来预测体内行为表明，所获得的 CaP 沉积物将作为催化剂迅速形成包含 Mg 的缺 CaP 层。非晶 CaP 磷灰石样沉积物促进了骨髓间充质干细胞的初始附着、增殖和成骨分化。最后，我们使用我们的方法对选择性激光烧结制成的钛合金 3D 多孔结构进行功能化。我们的研究使用了一种新颖且具有成本效益的方法来对临床相关金属表面进行功能化，以提高这些材料的生物活性，从而改善其临床性能。
