注银碳基生物医学材料的抗菌机理研究

Study on bactericidal mechanism of silver implanted carbon based biomedical materials

选用革兰氏阴性菌-大肠杆菌,采用平板菌落计数法对注银碳基生物医学材料样品直接接触和间接接触的抗菌效果进行对比.研究结果表明:注银后材料表面形成的富银层是材料抗菌性的主要原因.对注银剂量相同的样品,直接接触比其滤液的抗菌效果好,说明注银碳基材料的抗菌性是溶出的银离子和材料表面未溶出的络合状银离子共同作用的结果,且以银离子溶出杀菌为主.通过紫外光谱法探究银离子和细菌染色体DNA的相互作用机制,发现银离子与DNA之间存在静电和碱基作用,导致DNA分子天然构象遭到破坏,起到抗菌作用.

The bactericidal mechanism of Ag＋-implanted carbon based biomedical materials is investigated with Gram-negative E.coli.Standard agar dilution method is used to compare the antibacterial effects between immediate contact and mediate contact.The results show that Ag-rich surface layer is formed on the surface of material.With the same ion dose,the antibacterial effect of Ag＋-implanted carbon based biomaterial is better than its filtrate and it indicates that the antibacterial effect of Ag＋-implanted carbon based biomaterial is determined by both dissolved out silver ions and undissolved complex silver ions on the surface of materials.Further more,the dissolved silver ions play more important role in killing bacteria.The mechanism of interactions between the silver ions and DNA is studied by UV spectrum,namely,electrostatic and base effect exist between silver ions and DNA.The electrostatic reaction can destroy the natural framework of DNA molecular so that the bactericidal effect is carried out.