評估電解質溶液中鈷離子濃度對鈷氫氧基磷灰石磁特性之影響

氫氧基磷灰石在生物醫學領域是廣泛被使用的材料，使用電化學沉積法合成的鈷氫氧基磷灰石（CoHA）是由奈米等級球狀結晶所構成，而鈷離子取代比例的適當增加，對於飽和磁化強度以及生物活性皆具有提升效果。 若使用以往的電解質溶液配方並直接增加氯化亞鈷添加量，會導致試片上淺色CoHA沉積粉體分佈量逐漸減少，並且產生大量的深色結晶物。 本研究中藉由測試F1及F2兩種不同的電解質溶液配方以及調整電解質溶液成份參數以改善試片上淺色CoHA粉體分佈比例，同時增加鈷離子濃度以合成出具有更高鈷取代比例的CoHA，並評估對於粉體樣本磁特性的影響。 EDS及ICP-OES測試結果顯示，所製備的F2 CoHA粉體之缺鈣結構及元素分佈比例較為接近預期。 XRD測試顯示，當F1電解質溶液中鈷離子濃度遠高於製備CoHA所需求的比例時，會導至產生的沉積粉體中含有大量鈷粉，此為深色結晶物的主要成份。 SQUID測試結果顯示，F2-30 CoHA樣本具有較以往更高的鈷元素重量佔比以及較高的飽和磁化強度，可獲得良好的MRI影像對比度。 藉由數學模型所繪製的電解質溶液等效阻抗曲線，所計算出的正/反面電流密度及電場值，可說明試片上粉末沉積的模式。 生物降解測試顯示，粉體的酸性鈷離子釋出會影響磷酸鹽緩衝溶液的酸鹼度，進而影響鈣離子、磷酸根離子濃度以及磷酸鈣的沉積量。 以上結果顯示，F2配方具有較佳的鈷離子取代合成效果，而其中F2-30 CoHA樣本之磁特性測試結果符合預期設計目標，可做為 後續 MRI 及CT影像驗證用樣本。

Hydroxyapatite is a widely used material in biomedicine field, and the Cobalt hydroxyapatite (CoHA) synthesized by electrochemical deposition is composed by nano-grade spherical crystals, and appropriately increase the replacement ratio of cobalt ions can enhance the effect of saturation magnetization and biological activity. If previous electrolyte formula is used and directly increase the amount of cobalt chloride, the distribution of light-colored CoHA deposited powder on test piece will gradually reduce, and large amount of dark-colored crystals be produced. By testing two different electrolyte formulations F1 and F2 in this study, and adjusting electrolyte to improve the distribution ratio of light-colored CoHA powder on test piece, meanwhile increasing cobalt ion concentration to synthesize higher cobalt proportion of substitution CoHA, and evaluate influence to magnetic properties. EDS and ICP-OES test results show that F2 CoHA sample has expected calcium-deficient structure and element distribution ratio. XRD test result shows that F1 electrolyte’s cobalt ion concentration exceeded the preparation requirement ratio of CoHA will cause large amount of cobalt powder in deposited powder, which is the main component of dark-colored crystals. SQUID test result shows that F2-30 CoHA sample with higher weight ratio of cobalt ions than before also has stronger saturation magnetization, and good MRI image contrast be obtained. The calculated front / back current density and electric field of test pieces can explain the pattern of powder deposition by using the equivalent impedance curve of electrolyte drawn by mathematical model. Biodegradation test shows that the release of acidic cobalt ions from powder will affect the pH value of phosphate buffered saline,which affect the concentration of calcium and phosphate ions and calcium phosphate deposition. The above results show that F2 formula has better synthesis effect in cobalt ion substitution, and the magnetic properties test results of F2-30 CoHA sample meets the expected design purpose, and can be used as sample for subsequent MRI and CT imaging verification.