以微弧氧化法於鈦基材製備含銀之氫氧基磷灰石塗層生醫特性研究

摘要

氫氧基磷灰石（HA）具有優異的生醫活性與生醫相容性，在臨床上已被廣泛用來作為金屬醫材的表面塗層，然而，HA抗菌能力不足，而Ag是被公認最佳的抗菌劑，但添加後對生醫活性可能會產生不良的影響，添加量過多亦會產生細胞毒性。本研究目的為使用微弧氧化（MAO）於Ti基材表面製備含Ag之HA塗層，MAO參數設定二種放電電壓（300、400V），搭配固定的放電電流（0.6A）與放電時間（5min），電解液以0.2 mol/L醋酸鈣（C₄H₈CaO₅·H₂O）與0.1 mol/L磷酸二氫鈉（NaH₂PO₄·2H₂O）作為基礎溶液，並分別添加0、0.001與0.002 mol/L之硝酸銀（AgNO₃）。研究結果顯示，添加與未添加Ag之塗層表面皆可形成生醫性質優異的花狀結構，在添加Ag試件之EDS皆出現微量（0.11~0.66 at％）的銀元素，而XRD分析則無Ag或Ag之化合物出現，所有MAO試件塗層之化合物均為由Ti、Anatase、Rutile、HA與DCPD所組成，並呈現超親水性（接觸角≈0°）。在生醫活性試驗中，試件浸泡人工模擬體液7天即可生成大量磷灰石並幾乎覆蓋塗層表面，顯示在0、0.001與0.002 mol/L之AgNO₃添加量仍可維持相當優異的生醫活性。

Abstract

Hydroxyapatite (HA) exhibits excellent bioactivity and biocompatibility and has been widely used clinically as a surface coating for biometallic materials. However, HA has poor antibacterial properties. Silver (Ag) is recognized as the best antibacterial agent, but its addition may adversely affect bioactivity, and excessive amounts can cause cytotoxicity. This study aims to prepare silver-containing HA coatings on titanium substrates using micro-arc oxidation (MAO) under different applied voltages (300V and 400V) while maintaining a fixed applied current (0.6A) and duration (5 minutes). The electrolyte consists of 0.2 mol/L C₄H₈CaO₅•H₂O and 0.1 mol/L NaH₂PO₄•2H₂O as base solutions, with AgNO₃ added at concentrations of 0, 0.001, and 0.002 mol/L. It was found that the coating surface with and without Ag can form flower-like surface structures with excellent biomedical properties. A trace amount (0.11~0.66 at%) of Ag element was detected in the EDS spectrum of silver-added samples. However, XRD analysis of the MAO coatings showed no presence of Ag or Ag compounds. All specimens were composed of Ti, TiO₂-A (anatase), TiO₂-R (rutile), HA, and DCPD, and exhibited superhydrophilicity (contact angle ≈ 0°). In bioactivity tests, a large amount of apatite was produced, roughly covering the coating surface after immersion in artificial simulated body fluid (SBF) for 7 days. This finding indicates that excellent bioactivity can still be maintained when the addition amount of AgNO3 is 0, 0.001 and 0.002 mol/L.