钴铬合金表面飞秒激光图案化处理研究及其对成骨细胞/成纤维细胞的细胞行为影响

Cobalt-chromium (CoCr) based alloys are extensively used in orthopaedic surgery for their high strength and wear properties. Osseointegration of a material is possibly improved by specific topographical modifications, because the surface topography governs biocompatibility of material by influencing cell adhesion, proliferation, and cell morphology. Femtosecond laser irradiation is chosen to create micrometer and nanometer scale topographical features on CoCr surfaces in this project. Surface morphology and composition of metal were measured after laser irradiation. A simulation model of interaction between femtosecond laser and sample surface is established by COMSOL soft, and the variations of cell behavior induced by surface morphology of CoCr were systematically researched. The effect of oxides which appeared on CoCr surface during laser irradiation was analyzed. Microstructures of the alloys may be changed by it though the plasma which existed on the interface between oxide and CoCr. Furthermore, the function of oxides improving the biocompatibility of the alloys was also evaluated. Three kinds of factors were systemically studied including surface roughness, surface microstructures, and surface energy, which induced the cell behavior of osteoblasts/fibroblasts. The morphology parameters of CoCr alloy and corresponding process parameters of femtosecond laser were arranged, in order to fabricate a suitable microstructure on CoCr surface for cell growth. The relationship between CoCr surface morphology and focus position of femtosecond laser was investigated. Furthermore, a parameter compensation method was proposed to ensure the stability of morphology. This project will provide an important theoretical basis and experimental support for the improving of surface treatment of CoCr alloy implants, and it will promote the application of femtosecond laser in the surface treatment of porous CoCr implants fabricated by additive manufacturing technology.

钴铬合金因其具有的高强度和耐磨性而被广泛应用于骨科手术中。通过对材料表面进行适当的形貌修饰可以改善其生物相容性，有助于提高材料的骨整合。本项目拟采用飞秒激光对钴铬合金表面进行处理，通过对钴铬合金表面形貌、表面能以及表面成分变化进行表征，建立飞秒激光与合金表面相互作用的仿真模型，并系统研究其表面形貌变化对细胞行为所产生的影响。分析加工过程中出现的氧化物对合金表面微结构产生的影响，并评估其对改善材料生物相容性的贡献。阐明表面粗糙度、表面微结构和表面能在调控细胞行为中的作用和贡献。整理适合细胞生长的钴铬合金表面形貌特征参数范围及相应的飞秒激光加工参数，考察焦点变化对表面形貌的影响，提出保证表面形貌的稳定的参数补偿方法。本项目将为钴铬合金植入物的表面处理提供重要的理论基础和实验支持，对未来飞秒激光加工技术应用于3D打印钴铬合金多孔结构的表面处理上具有一定的推动作用。

钴铬合金因其优秀的耐摩性、耐腐蚀性和良好的生物相容性而被广泛应用于制备齿科、骨科以及血管支架等植入物。有大量研究表明，具有微纳复合结构的粗糙植入物表面比光滑的植入物表面更有助于提高植入物的骨整合，因此多种改性手段被应用于植入物的表面处理。飞秒激光加工方法是一种无接触、无污染的方便快捷加工技术。对于飞秒激光在钛合金表面改性方面进行了大量的研究，但是有关飞秒激光对钴铬合金表面改性的研究报道有限。本项目针对这一情况开展了采用飞秒激光对钴铬合金进行表面处理的研究。本项目取得的研究成果包括：（1）通过对不同飞秒激光加工参数下制备的钴铬合金表面形貌、表面能以及表面成分变化进行表征，研究飞秒激光与钴铬合金表面的相互作用机制，发现具有铁磁性的钴与等离子体电磁场响应，导致堆积在飞秒激光烧蚀沟槽两侧的微纳合金颗粒随着脉冲重叠率的增加组成片状结构，最终形成穹顶覆盖在沟槽上方。（2）通过拉曼光谱观察到出现在脊状结构顶部的纳米三氧化二铬的表面振动模并首次对其进行指认。（3）通过分析合金表面形貌变化对细胞行为所产生的影响，评估了在改性过程中产生的表面周期结构和纳米氧化物聚合体对改善材料生物相容性的影响。本项目对未来飞秒激光加工技术应用于3D打印钴铬合金多孔结构的表面处理上具有一定的推动作用。本项目在项目执行期间共发表标注论文3 篇，申请专利1项。