氫氧基磷灰石 (Ca10(PO4)6(OH)2, HA) 相似於人體骨骼和牙齒的礦物成分，由於其良好的生物相容性和生物活化性，因此廣泛的應用在包括骨填料、表面塗層以及支架上。由於奈米級氫氧基磷灰石比一般的氫氧基磷灰石具有較高的表面能，因此具有更好的生物性質。特別的是，人體內的天然磷灰石含有約3-8 %(w/w)的碳酸鹽，此外，也預計奈米級氫氧基磷灰石將有更好的生物活性。本實驗是想要利用仿生法的過程來合成創造新的材料，也就是說，無機物和一個複雜的有機高分子的基質蛋白、多醣或脂類結合，不僅可控制合成粉末顆粒的大小和形狀，同時也能控制粉末顆粒團聚現象發生。本研究係利用水熱法，將碳酸鈣(CaCO3)和磷酸(H3PO4)溶液在密閉的高壓力釜中產生反應。實驗結果發現，添加植物皮萃取物在150 ºC 持溫48 h，pH值為10 的條件下，可以得到單相的棒狀奈米級氫氧基磷灰石結晶相。此外，蛋殼和生物分子的有效利用，可以大大提高經濟效率以及減少對環境的污染。

Hydroxyapatite(Ca10(PO4)6(OH)2, HA) is similar to the mineral constituents of human bone and teeth. Because of its excellent biocompatibility and bioactivity, it is applied widely in bone fillers, surface coatings, and unloaded scaffolds.Nano-HA particles exhibit enhanced biological properties compared with normal HA particles because of their high surface energy and increased specific area. The natural apatite in the human body contains approximately 3%-8% (w/w) carbonate. Nanostructured HA is expected to have greater bioactivity than HA with coarser crystals does. Creating new synthetic materials by mimicking the processes involves combining minerals with a complex organic macromolecular matrix of proteins, polysaccharides and lipids to control the size and shape of synthesized particles. We used a hydrothermal method to create carbonate (CaCO3) and phosphoric acid (H3PO4）solutions that react with each other and form high pressure in a closed autoclave. A single phase of HA, the nanorod crystalline phase, was obtained when plant peel extracts were added and a temperature of 150 ºC and a pH value of 10 were maintained for 48 h.The effective use of eggshell and biomolecule waste greatly enhances economic efficiency and reduces
environmental pollution.