Department of Materials Science and Technology, Nagaoka University of Technology, Kamitomioka 1603-1, Nagaoka, Niigata 940-2188, Japan.
Japan Society for the Promotion of Science, 5-3-1 Koji-machi, Chiyoda-ku, Tokyo 102-0083, Japan.
Phys Chem Chem Phys. 2022 Mar 16;24(11):6788-6802. doi: 10.1039/d1cp04768j.
Silicate-containing hydroxyapatite (SiHA) particles were synthesized and functionalized with polyethylene glycol-silane (PEG-silane) for clarifying the effect of the bioceramic surface hydration layer states on the collagen (Col) fibrillation degree. Plate-like SiHA particles were obtained containing the SiO ion inside and/or outside the particles. PEG-silane was successfully functionalized on SiHA particles, and the hydration layer and Col adlayer states on the particles were precisely investigated for exemplifying the importance of the water molecular states at the interface. The ratio of free to intermediate water in the hydration layers of the particles decreased when containing silicate components, and it significantly increased with increasing PEG-silane molecular occupancy, where the asymmetric stretching vibration component ratio in the free water clearly increased. In a quartz crystal microbalance with dissipation (QCM-D) measurement, the frequency change (Δ) and the energy dissipation change (Δ) values increased with Col adsorption on the particles for 32-34 min and then Δ slightly increased (or stopped increasing) and Δ dramatically increased, indicating the effective water mobility and state changes with the Col fibrillation at the interface. The Col fibrillation degree evaluated by tan and the protein secondary structure of the adlayers clearly increased due to the PEG-silane functionalization, and the tendency was supported by the increase in the fibril density under SEM observation. Surprisingly, it was found that the fibrillation degree based on the protein secondary structure was significantly correlated with the asymmetric stretching vibration component ratio in the free water molecules of the hydration layer on the particles, suggesting the importance of the hydration layer states on bioceramics for controlling Col fibrillation.
含硅羟基磷灰石（SiHA）颗粒被合成，并通过聚乙二醇硅烷（PEG-silane）进行功能化，以澄清生物陶瓷表面水合层状态对胶原蛋白（Col）纤度的影响。得到了含有 SiO 离子的板状 SiHA 颗粒，位于颗粒内部和/或外部。PEG-silane 成功地在 SiHA 颗粒上进行了功能化，并且对颗粒上的水合层和 Col 吸附层状态进行了精确研究，以例证界面水分子状态的重要性。当含有硅酸盐成分时，颗粒水合层中自由水和中间水的比例降低，而随着 PEG-silane 分子占有率的增加，其显著增加，其中自由水中不对称伸缩振动分量的比例明显增加。在石英晶体微天平（QCM-D）测量中，随着 Col 在颗粒上的吸附，频率变化（Δ）和能量耗散变化（Δ）值增加了 32-34 分钟，然后Δ略微增加（或停止增加），而Δ急剧增加，表明界面处 Col 纤维化时有效水的流动性和状态发生了变化。通过 tan 和吸附层中蛋白质二级结构评估的 Col 纤维化程度由于 PEG-silane 功能化而明显增加，并且这种趋势得到了 SEM 观察下纤维密度增加的支持。令人惊讶的是，发现基于蛋白质二级结构的纤维化程度与颗粒水合层中自由水分子的不对称伸缩振动分量的比例显著相关，这表明生物陶瓷水合层状态对控制 Col 纤维化的重要性。
