SEG-CEMMPRE Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra, Portugal.
CEB, Centre of Biological Engineering, LIBRO-Laboratório de Investigação em Biofilmes Rosário Oliveira, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal.
ACS Appl Mater Interfaces. 2020 Jun 3;12(22):24555-24563. doi: 10.1021/acsami.0c02821. Epub 2020 May 20.
The purpose of this work is the development of Ag/a:C and Ag-Au/a:C coatings for ureteral stents, to provide them with antimicrobial characteristics. Silver was selected because of its well-known antibacterial properties, while gold was included to assess its capacity to accelerate the silver ion release forming a galvanic couple between Au and Ag. Thus, the metallic (Ag) and bimetallic clusters (Ag-Au) were produced by three different configurations: (i) unbalanced magnetron sputtering (conventional sputtering), (ii) plasma gas condensation process, and by (iii) a combination between both previous approaches. Coatings with Ag-Au bimetallic clusters were characterized by transmission electron microscopy (TEM) in order to study the arrangement (alloy, core-shell, and galvanic couple) of these particles in the carbon matrix. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to quantify the Ag ions released through artificial urine from the different coatings deposited on thermoplastic polyurethane tape (one of the materials used in the manufacture of the ureteral stent ). Then, the antibacterial and cytotoxicity properties of Ag and Ag-Au/a:C coatings were evaluated. TEM shows that a biphasic structure was not detected, thus not allowing to anticipate the establishment of a galvanic couple. The ICP-OES results demonstrate that the silver ionization is mainly a function of the amount of silver incorporated in the amorphous carbon (a:C) matrix, and the formation of a bimetallic alloy has a detrimental effect on release of the silver ions. The antibacterial activity was regulated by the silver ionization mechanisms because the coatings with higher Ag release had a higher antibacterial activity.
本工作的目的是开发用于输尿管支架的 Ag/a:C 和 Ag-Au/a:C 涂层，为其提供抗菌特性。选择银是因为其众所周知的抗菌性能，而金则被包括在内，以评估其形成金-银电偶对加速银离子释放的能力。因此，通过三种不同的配置生产了金属（Ag）和双金属簇（Ag-Au）：（i）不平衡磁控溅射（常规溅射），（ii）等离子体气体冷凝过程，以及（iii）两者的组合。通过透射电子显微镜（TEM）对具有 Ag-Au 双金属簇的涂层进行了表征，以研究这些颗粒在碳基质中的排列（合金、核壳和电偶）。电感耦合等离子体发射光谱（ICP-OES）用于定量分析从沉积在热塑性聚氨酯带（输尿管支架制造中使用的材料之一）上的不同涂层中通过人工尿液释放的 Ag 离子。然后，评估了 Ag 和 Ag-Au/a:C 涂层的抗菌和细胞毒性特性。TEM 表明未检测到双相结构，因此不能预期建立电偶。ICP-OES 结果表明，银的离子化主要是银在非晶态碳（a:C）基质中含量的函数，而双金属合金的形成对银离子的释放有不利影响。抗菌活性受银离子化机制的调节，因为具有更高 Ag 释放的涂层具有更高的抗菌活性。
