镁合金表面非晶/多巴胺复合层的制备及模拟体内微动摩擦学行为研究

Refering to the requirements for the degradable materials in the clinical treatment of fracture fixation at the present stage, Mg-Zn-Ca alloy is chosen as the matrix and an amorphous layer is fabricated on the surface of the magnesium alloy by means of laser amorphousizing technique. The PDA film is then deposited on the amorphous layer to increase its bone inductivity and conductivity. The composite structure of crystalline matrix / amorphous layer / organic film is thus fabricated to meet the comprehensive requirements of body micro-environment for strength - corrosion resistance - osteoconductivity. A fretting device is designed to simulate the environment of human body. Using the method combined with experimental research theoretical analysis and numerical simulation, changes of mechanical strength in the degradation process will be studied systematically, and fretting biotribology behavior under the combined action of both mechanics and biology in simulated body fluid will also be investigated. A reasonable model of corrosion wear will be proposed to elucidate the corrosive wear mechanism under the synergistic action between fretting and bio-corrosion in the humoral environment. The decline law of the strength in accordance with degradation time and its regulation mechanism will be figured out to solve a series of forward-looking key scientific theories regarding controlled degradation, mechanical adaptation, and biological friction involved in the clinical applications. The target of the physiological adaptation of magnesium alloy, including controlled degradation absorption and tissue repairing in the human body, will be achieved, and the theoretical basis for its clinical applications will be provided.

针对当前骨折内固定治疗对可降解材料的要求，以非晶形成能力较高的Mg-Zn-Ca合金为基体，采用激光表面非晶化法在其表面形成非晶层，然后再沉积聚多巴胺薄膜(PDA)，增加其骨诱导和骨传导性，获得“晶态基体/非晶层/有机膜”的镁合金多层复合结构，以达到人体微环境对“强度-耐腐蚀性-骨传导性”的综合要求。设计出模拟人体环境的微动磨损装置，结合实验研究、理论分析和模拟仿真，系统研究镁合金在降解过程中的力学变化，以及在模拟体液中“力学和生物学”双因素共同作用下的微动生物摩擦学行为，建立合理的腐蚀磨损模型，阐明体液环境下，微动磨损和生物腐蚀协同作用下的腐蚀磨损机制，得出强度随降解时间的衰变规律及调控机制，解决临床治疗应用中涉及到的可控降解、力学适配、生物摩擦等一些前瞻的关键科学问题，以实现镁合金在人体环境下可控降解吸收与组织修复生理适配的目标，为镁合金的最终临床应用提供理论基础。

针对当前骨折内固定治疗对可降解材料的要求，以非晶形成能力较高的Mg-Zn-Ca合金为基体，采用激光表面非晶化法在合金表面形成非晶层，然后沉积活性有机涂层，获得“晶态基体/非晶层/有机膜”的镁合金多层复合结构，增加了器件的骨诱导和骨传导性，实现了人体微环境对“强度-耐腐蚀-骨传导”的综合要求。项目围绕镁合金在人体环境下可控降解吸收与组织修复生理适配的目标，研究了Mg-Zn-Ca合金表面非晶层的形成和可控降解中的关键应用基础科学问题，取得的主要研究结论和成果如下：1）揭示了Mg-Zn-Ca合金激光加工表面非晶层的形成条件，优化了功率、速度、扫描方式等工艺技术参数，得到了性能稳定的非晶涂层；2）搭建了模拟人体环境的微动磨损装置，结合实验研究、理论分析和模拟仿真，建立了合理的腐蚀磨损模型；3）阐明了体液环境下，微动磨损和生物腐蚀协同作用下的腐蚀磨损机制，得到复合涂层的强度随降解时间的衰变规律及调控机制；4）解决了临床治疗应用中涉及到的可控降解、力学适配、生物摩擦等一些前瞻的关键科学问题，验证了技术的可行性。项目研究在国内外学术期刊上发表论文14篇，其中SCI检索13篇；授权国家发明专利5项；培养硕士生4人；部分相关成果获江苏省科学技术二等奖1项。研究成果促进了镁合金在新一代可降解吸收内固定器械的临床应用，提升了镁合金的医用经济价值，同时对镁合金在其他领域的应用也将具有广泛的借鉴作用。