4.7 Article

Tunable Enzyme-Assisted Mineralization of Apatitic Calcium Phosphate by Homogeneous Catalysis

期刊

出版社

MDPI
DOI: 10.3390/ijms24010043

关键词

biomineralization; hydroxyapatite; X-ray powder diffraction; alkaline phosphatase; carbonate; fluoride

向作者/读者索取更多资源

In this study, the effects of enzyme substrate concentration and fluoride concentration on the obtained minerals in enzyme-assisted mineralization were investigated. X-ray diffraction, infrared spectroscopy, and X-ray photoelectron spectroscopy were used to analyze the crystal structure and chemical composition of the minerals. The results showed the formation of substituted hydroxyapatite in all conditions, with expansion of the crystal unit cell parameters when the enzyme substrate concentration increased, and contraction of the crystal unit cell parameters and the formation of elongated, well-crystallized rods when the fluoride concentration increased. Complementary IR and XPS data indicated that these trends were explained by the incorporation of substituted ions in the hydroxyapatite lattice at different positions.
While it has long been mimicked by simple precipitation reactions under biologically relevant conditions, calcium phosphate biomineralization is a complex process, which is highly regulated by physicochemical factors and involves a variety of proteins and other biomolecules. Alkaline phosphatase (ALP), in particular, is a conductor of sorts, directly regulating the amount of orthophosphate ions available for mineralization. Herein, we explore enzyme-assisted mineralization in the homogeneous phase as a method for biomimetic mineralization and focus on how relevant ionic substitution types affect the obtained minerals. For this purpose, mineralization is performed over a range of enzyme substrate concentrations and fluoride concentrations at physiologically relevant conditions (pH 7.4, T = 37 degrees C). Refinement of X-ray diffraction data is used to study the crystallographic unit cell parameters for evidence of ionic substitution in the lattice, and infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) are used for complementary information regarding the chemical composition of the minerals. The results show the formation of substituted hydroxyapatite (HAP) after 48 h mineralization in all conditions. Interestingly, an expansion of the crystalline unit cell with an increasing concentration of the enzyme substrate is observed, with only slight changes in the particle morphology. On the contrary, by increasing the amount of fluoride, while keeping the enzyme substrate concentration unchanged, a contraction of the crystalline unit cell and the formation of elongated, well-crystallized rods are observed. Complementary IR and XPS data indicate that these trends are explained by the incorporation of substituted ions, namely CO32- and F-, in the HAP lattice at different positions.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.7
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据