Mocanu Aurora, Cadar Oana, Frangopol Petre T, Petean Ioan, Tomoaia Gheorghe, Paltinean Gertrud-Alexandra, Racz Csaba Pal, Horovitz Ossi, Tomoaia-Cotisel Maria
Faculty of Chemistry and Chemical Engineering, Physical Chemistry Centre, Chemical Engineering Department, Babes-Bolyai University of Cluj-Napoca, 11 Arany J. Street, 400028 Cluj-Napoca, Romania.
INCDO INOE 2000, Research Institute for Analytical Instrumentation, 67 Donath Street, 400293 Cluj-Napoca, Romania.
R Soc Open Sci. 2021 Jan 13;8(1):201785. doi: 10.1098/rsos.201785. eCollection 2021 Jan.
Multi-substituted hydroxyapatites (ms-HAPs) are currently gaining more consideration owing to their multifunctional properties and biomimetic structure, owning thus an enhanced biological potential in orthopaedic and dental applications. In this study, nano-hydroxyapatite (HAP) substituted with multiple cations (Sr, Mg and Zn) for Ca and anion ( ) for and OH, specifically HAPc-5%Sr and HAPc-10%Sr (where HAPc is HAP-1.5%Mg-0.2%Zn-0.2%Si), both lyophilized non-calcined and lyophilized calcined, were evaluated for their ions release. These nanomaterials were characterized by scanning electron microscopy, field emission-scanning electron microscopy and energy-dispersive X-ray, as well as by atomic force microscope images and by surface specific areas and porosity. Further, the release of cations and of phosphate anions were assessed from nano-HAP and ms-HAPs, both in water and in simulated body fluid, in static and simulated dynamic conditions, using inductively coupled plasma optical emission spectrometry. The release profiles were analysed and the influence of experimental conditions was determined for each of the six nanomaterials and for various periods of time. The pH of the samples soaked in the immersion liquids was also measured. The ion release mechanism was theoretically investigated using the Korsmeyer-Peppas model. The results indicated a mechanism principally based on diffusion and dissolution, with possible contribution of ion exchange. The surface of ms-HAP nanoparticles is more susceptible to dissolution into immersion liquids owing to the lattice strain provoked by simultaneous multi-substitution in HAP structure. According to the findings, it is rational to suggest that both materials HAPc-5%Sr and HAPc-10%Sr are bioactive and can be potential candidates in bone tissue regeneration.
多取代羟基磷灰石（ms-HAPs）由于其多功能特性和仿生结构，目前正受到更多关注，因此在骨科和牙科应用中具有增强的生物学潜力。在本研究中，对用多种阳离子（Sr、Mg和Zn）取代Ca以及用阴离子（ ）取代 和OH的纳米羟基磷灰石（HAP），特别是冻干未煅烧和冻干煅烧的HAPc-5%Sr和HAPc-10%Sr（其中HAPc是HAP-1.5%Mg-0.2%Zn-0.2%Si）的离子释放情况进行了评估。这些纳米材料通过扫描电子显微镜、场发射扫描电子显微镜和能量色散X射线进行表征，以及通过原子力显微镜图像、表面比面积和孔隙率进行表征。此外，使用电感耦合等离子体发射光谱法，在静态和模拟动态条件下，评估了纳米HAP和ms-HAPs在水和模拟体液中的阳离子和磷酸根阴离子的释放情况。分析了六种纳米材料在不同时间段的释放曲线，并确定了实验条件的影响。还测量了浸泡在浸泡液中的样品的pH值。使用Korsmeyer-Peppas模型对离子释放机制进行了理论研究。结果表明，其机制主要基于扩散和溶解，可能有离子交换的作用。由于HAP结构中同时进行多取代引起的晶格应变，ms-HAP纳米颗粒的表面更容易溶解到浸泡液中。根据研究结果，合理的建议是HAPc-5%Sr和HAPc-10%Sr这两种材料都具有生物活性，并且可能是骨组织再生的潜在候选材料。
