不同雷射指示功率披覆TiO2於活化熱處理鉭基材之生物活性研究

A Study on the Bioactivity of Cladding TiO2 on Tantalum Substrate after Heat Treatment Activation Using Various Specific Laser Power

鉭金屬因具有優良的生醫性質，且其彈性係數低、疲勞強度強，能有效改善早期不鏽鋼、鈷鉻合金與鈦合金等生醫材料所面臨之應力遮蔽效應與有害金屬離子釋放等問題。為使鉭金屬達到更佳之生物活性，本研究使用Nd：YAG雷射披覆TiO2粉末於NaOH活化熱處理後之鉭金屬基材上，使用之雷射指示功率為10.42 J/mm3~33.33 J/mm3等，以探討指示功率大小對披覆層生物活性之影響。研究結果顯示，鉭金屬經NaOH活化熱處理後會在表面形成TaOH層。披覆層之結合特性與生物活性試驗結果亦顯示，在低指示功率（10.42與12.5 J/mm3）下，披覆材無法與基材成功結合，所形成之披覆層易脫落，浸泡人工模擬體液(SBF)後，表面僅有結晶物質生成，幾乎沒有沉積物出現；在中指示功率(25 J/mm3)下，浸泡SBF初期即有磷灰石生成，生物活性明顯提升；而在較高(33.33 J/mm3)的指示功率下，因披覆層與基材結合最佳，在浸泡SBF後亦生成最多之磷灰石，顯示其生物活性最佳。在硬度量測結果顯示中、高指示功率(25 J/mm3、27.78 J/mm3、33.33 J/mm3)下硬度值高於低指示功率(13.89 J/mm3、16.67 J/mm3、20.83 J/mm3)。

Due to its excellent biocompatible properties like low coefficient of elasticity, good corrosion resistance and high fatigue strength, tantalum (Ta) metal is able to effectively avoid the stress shielding effect, toxic metal ion release of stainless steel, cobalt-chromium and titanium alloys. In order to achieve better Ta bioactivity, in this study, we use Nd:YAG laser to clad TiO2 powder on the tantalum metal substrate after NaOH heat treatment activation. The applied specific power of the laser was from 10.42 J/mm3 - 33.33 J/mm3, so as to investigate the effect of the specified power magnitude to the bioactivity of the cladded layer. The results showed that Ta metal forms a TaOH layer on the surface after NaOH heat treatment activation. For the low specific power (10.42~12.5 J/mm3) specimens, the coated material could not be successfully combined with the substrate, and the cladded layer easily turned into scrap. After soaking it in the simulated body fluid (SBF), only crystalline materials were generated on the surface, almost without any precipitates. For the medium specific power (25 J/mm3) specimen, upon initial immersion in SBF, an apatite was generated, and bioactivity improved significantly. For the high specific power (25~33.33 J/ mm3) specimens, because the combination of the cladded layer and substrate was at its best, a great quantity of hydroxyapatite was generated after immersion in SBF, showing the best biological activity. Furthermore, the hardness of cladding layer under medium and high specific power were greater than that of in the lower specific power specimens.