Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Department of Biological & Agricultural Engineering, Louisiana State University and Agricultural Center, Baton Rouge, Louisiana 70803, United States.
ACS Appl Mater Interfaces. 2021 Jun 16;13(23):26824-26840. doi: 10.1021/acsami.1c09034. Epub 2021 Jun 7.
Hydroxyapatite (HA)-coated metals are biocompatible composites, which have potential for various applications for bone replacement and regeneration in the human body. In this study, we proposed the design of biocompatible, flexible composite implants by using a metal mesh as substrate and HA coating as bone regenerative stimulant derived from a simple sol-gel method. Experiments were performed to understand the effect of coating method (dip-coating and drop casting), substrate material (titanium and stainless steel) and substrate mesh characteristics (mesh size, weave pattern) on implant's performance. HA-coated samples were characterized by X-ray diffractometer, transmission electron microscope, field-emission scanning electron microscope, nanoindenter, polarization and electrochemical impedance spectroscopy, and biocompatibility test. Pure or biphasic nanorod HA coating was obtained on mesh substrates with thicknesses varying from 4.0 to 7.9 μm. Different coating procedures and number of layers did not affect crystal structure, shape, or most intense plane reflections of the HA coating. Moduli of elasticity below 18.5 GPa were reported for HA-coated samples, falling within the range of natural skull bone. Coated samples led to at least 90% cell viability and up to 99.5% extracellular matrix coverage into a 3-dimensional network (16.4% to 76.5% higher than bare substrates). Fluorescent imaging showed no antagonistic effect of the coatings on osteogenic differentiation. Finer mesh size enhanced coating coverage and adhesion, but a low number of HA layers was preferable to maintain open mesh areas promoting extracellular matrix formation. Finally, electrochemical behavior studies revealed that, although corrosion protection for HA-coated samples was generally higher than bare samples, galvanic corrosion occurred on some samples. Overall, the results indicated that while HA-coated titanium grade 1 showed the best performance as a potential implant, HA-coated stainless steel 316 with the finest mesh size constitutes an adequate, lower cost alternative.
羟基磷灰石（HA）涂层金属是生物相容性复合材料，具有在人体中替代和再生骨骼的各种应用的潜力。在这项研究中，我们提出了使用金属网作为基底和 HA 涂层作为骨再生刺激物的生物相容性、柔性复合植入物的设计，该涂层是通过简单的溶胶-凝胶方法获得的。进行了实验以了解涂层方法（浸涂和滴铸）、基底材料（钛和不锈钢）和基底网孔特性（网孔尺寸、编织图案）对植入物性能的影响。通过 X 射线衍射仪、透射电子显微镜、场发射扫描电子显微镜、纳米压痕仪、极化和电化学阻抗谱以及生物相容性测试对 HA 涂层样品进行了表征。在网孔基底上获得了纯或双相纳米棒 HA 涂层，厚度从 4.0 到 7.9 μm 不等。不同的涂层程序和层数不影响 HA 涂层的晶体结构、形状或最强平面反射。报道的 HA 涂层样品的弹性模量低于 18.5 GPa，处于天然颅骨骨的范围内。涂层样品导致细胞活力至少达到 90%，细胞外基质覆盖率高达 3D 网络的 99.5%（比裸基底高 16.4%至 76.5%）。荧光成像显示涂层对成骨分化没有拮抗作用。更细的网孔尺寸增强了涂层的覆盖率和附着力，但保持开放网孔区域以促进细胞外基质形成的少量 HA 层更为可取。最后，电化学行为研究表明，尽管 HA 涂层样品的腐蚀保护通常高于裸样品，但一些样品发生了电偶腐蚀。总的来说，结果表明，尽管 HA 涂层的 1 级钛表现出作为潜在植入物的最佳性能，但具有最细网孔尺寸的 HA 涂层的 316 级不锈钢构成了一种足够的、成本较低的替代方案。
