Department of Physics, Department of Materials Science and Engineering, Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
Center for Human Tissues and Organs Degeneration, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
Biomater Adv. 2022 Mar;134:112701. doi: 10.1016/j.msec.2022.112701. Epub 2022 Feb 8.
Polypyrrole (PPy) which is a conductive polymer with excellent biocompatibility has enormous potential in implantable electronics. However, pristine PPy does not have sufficient bacterial resistance and hence, bacterial infection poses serious threats in vivo. Silver is an excellent antibacterial agent but the optimal concentration is critical because excessive silver is detrimental to human health. In this study, electrochemical polymerization is carried out to fabricate PPy coatings and silver ions (Ag) are introduced by plasma immersion ion implantation (PIII). The optimal Ag ion fluence is determined by monitoring the antibacterial efficiency and cytotoxicity. Our results show that the optimal balance between the antibacterial ability and cytocompatibility can be attained from sample Ti-PPy@Ag-4 implanted with a silver ion fluence of 4 × 10 ions cm. In addition to retaining good cytocompatibility, 92% of the bacteria Staphylococcus aureus (S. aureus) can be eliminated. The intricate balance between antibacterial effects and biocompatibility arises from the levels of intracellular reactive oxygen species (ROS) in S. aureus and MC3T3-E1 osteoblasts on Ti-PPy@Ag-4. The antibacterial capability and biocompatibility are verified by the subcutaneous infection model in rats in vivo. The results reveal a simple strategy to improve the bacterial resistance of polymers such as PPy while not compromising the inherent biosafety of the materials. To the best of our knowledge, this is the first attempt to functionalize PPy by Ag PIII to create the proper balance between the antibacterial capacity and biosafety of biomedical implants.
聚吡咯（PPy）是一种具有优异生物相容性的导电聚合物，在可植入电子领域具有巨大的潜力。然而，原始的 PPy 没有足够的抗菌性，因此，细菌感染在体内会构成严重威胁。银是一种极好的抗菌剂，但最佳浓度是关键，因为过量的银对人体健康有害。在这项研究中，通过电化学聚合来制备 PPy 涂层，并通过等离子体浸没离子注入（PIII）引入银离子（Ag）。通过监测抗菌效率和细胞毒性来确定最佳的 Ag 离子注入剂量。我们的结果表明，从银离子注入剂量为 4×10 离子/cm 的 Ti-PPy@Ag-4 样品中可以获得抗菌能力和细胞相容性之间的最佳平衡。除了保持良好的细胞相容性外，还可以消除 92%的金黄色葡萄球菌（S. aureus）。Ti-PPy@Ag-4 上金黄色葡萄球菌和 MC3T3-E1 成骨细胞内的细胞内活性氧（ROS）水平导致了抗菌效果和细胞相容性之间的复杂平衡。通过体内大鼠皮下感染模型验证了其抗菌性能和生物相容性。结果表明了一种提高聚合物（如 PPy）抗菌性而不损害材料固有生物安全性的简单策略。据我们所知，这是首次尝试通过 Ag PIII 功能化 PPy，以在生物医学植入物的抗菌能力和生物安全性之间创造适当的平衡。
