Key Lab of Inorganic Coating Materials CAS, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Science, Beijing 100049, China.
Langmuir. 2021 Sep 14;37(36):10786-10796. doi: 10.1021/acs.langmuir.1c01666. Epub 2021 Aug 31.
Defects in hydroxyapatite (HA) have attracted increasing research interest due to their significant functions to increase the bioactivity and antibacterial ability of hard-tissue implants. However, little is known about the natural property and functional mechanism of the defects in HA. Herein, we reported on the defect property concerned with the coordination state and charge distribution in Al doped HA, as well as the consequent interface and protein capture ability for improved antibacterial activity. Systemic investigations suggested that Al replacing Ca in HA induced coordination defect with decreased coordination number and bond distance, caused charge transfer and redistribution of surrounding O atom and resulted in an increase in negative charge of coordinated O atoms. These O atoms coordinated with Al further served as docking sites for lysozyme molecules via electrostatic and H-bonding interaction. The capacity of lysozyme adsorption for Al-HA increased approximately 10-fold more than that of HA, which significantly increased the antibacterial activity through lysozyme-catalyzed splitting of cell wall of bacteria. Moreover, in vitro studies indicated that Al-HA materials showed good cytocompatibility. These findings not only provided new insights into the important effect of defects on the performances of HA biomaterials by modulation of the coordination state, charge distribution, and chemical activity, but also proposed a promising method for efficient antibacterial activity of HA biomaterials.
由于羟基磷灰石（HA）的缺陷能够显著提高硬组织植入物的生物活性和抗菌能力，因此引起了越来越多的研究兴趣。然而，对于 HA 缺陷的天然性质和功能机制知之甚少。在此，我们报道了 Al 掺杂 HA 中与配位状态和电荷分布有关的缺陷性质，以及由此产生的界面和蛋白质捕获能力，以提高抗菌活性。系统研究表明，HA 中 Al 取代 Ca 会导致配位缺陷，配位数和键距减小，引起周围 O 原子的电荷转移和重新分布，导致配位 O 原子的负电荷增加。这些与 Al 配位的 O 原子进一步通过静电和氢键相互作用作为溶菌酶分子的对接位点。与 HA 相比，Al-HA 的溶菌酶吸附能力增加了约 10 倍，通过溶菌酶催化细菌细胞壁的分裂，显著提高了抗菌活性。此外，体外研究表明 Al-HA 材料具有良好的细胞相容性。这些发现不仅为通过调节配位状态、电荷分布和化学活性对 HA 生物材料性能的重要影响提供了新的见解，而且为提高 HA 生物材料的抗菌活性提出了一种很有前途的方法。
