Materials Science and Engineering Program, University of California, Riverside, Riverside, California 92521, United States.
Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093, United States.
ACS Appl Bio Mater. 2022 Jun 20;5(6):2664-2675. doi: 10.1021/acsabm.2c00119. Epub 2022 Jun 7.
Transparent yttria-stabilized zirconia (YSZ) ceramics are promising for cranial window applications because of their good mechanical and optical properties as well as biocompatibility. YSZ discs with different yttria concentrations were either processed via current-activated pressure-assisted densification (CAPAD) using commercial nanoparticles or densified via spark plasma sintering (SPS) using pyrolysis-synthesized nanoparticles in-house. This study provided critical results to screen composition, processing, microstructure, and cytocompatibility of transparent YSZ discs for cranial window applications. CAPAD-processed YSZ discs with 6 or 8 mol % yttria (6YSZ and 8YSZ) and SPS-densified YSZ discs with 4 mol % yttria (4YSZ_P) showed 200-350 nm polycrystalline grains containing 20-30 nm crystallite domains. SPS-densified YSZ discs with 8 mol % yttria (8YSZ_P) showed larger polycrystalline grains of 819 ± 155 nm with 29 ± 5 nm crystallite domains. CAPAD-processed YSZ discs with 3 mol % yttria (3YSZ) showed 39 ± 9 nm grains. Bone-marrow-derived stem cells (BMSCs) on the polished YSZ discs showed statistically higher spreading areas than those on the unpolished YSZ discs of the same compositions. Generally, polished 8YSZ, 4YSZ_P, and 8YSZ_P discs and unpolished 8YSZ_R, 4YSZ_PR, and 8YSZ_PR discs had lower average cell adhesion densities than other YSZ discs under direct contact conditions. Under indirect contact conditions, all the YSZ disc groups showed similar average cell adhesion densities to the Cell-only control. The groups of polished 4YSZ_P and 8YSZ_P discs, unpolished 4YSZ_PR and 8YSZ_PR discs, and particle control of 8YSZ_Pnp showed higher Y ion concentrations than other groups. No mineral deposition was detected on the polished YSZ discs after cell culture. Considering multiple factors such as cytocompatibility, cell adhesion density, Y ion release, mineral deposition, and optical transparency collectively, 8YSZ may be the best candidate for the cranial window applications. Further studies are needed to evaluate the long-term transparency and biocompatibility of YSZ discs.
透明氧化钇稳定氧化锆（YSZ）陶瓷因其良好的机械和光学性能以及生物相容性，有望应用于颅窗。不同氧化钇浓度的 YSZ 圆盘分别通过使用商业纳米粒子的电流激活压力辅助致密化（CAPAD）或通过使用内部热解合成纳米粒子的火花等离子体烧结（SPS）进行致密化。这项研究提供了关键结果，用于筛选用于颅窗应用的透明 YSZ 圆盘的组成、加工、微观结构和细胞相容性。具有 6 或 8 摩尔%氧化钇（6YSZ 和 8YSZ）的 CAPAD 处理的 YSZ 圆盘和具有 4 摩尔%氧化钇（4YSZ_P）的 SPS 致密化的 YSZ 圆盘显示出 200-350nm 的多晶晶粒，包含 20-30nm 的微晶畴。具有 8 摩尔%氧化钇（8YSZ_P）的 SPS 致密化的 YSZ 圆盘显示出较大的多晶晶粒，粒径为 819±155nm，微晶畴为 29±5nm。具有 3 摩尔%氧化钇（3YSZ）的 CAPAD 处理的 YSZ 圆盘显示出 39±9nm 的晶粒。在抛光的 YSZ 圆盘上的骨髓源性干细胞（BMSCs）比具有相同成分的未抛光 YSZ 圆盘上的 BMSCs 具有统计学上更高的扩展面积。一般来说，在直接接触条件下，与其他 YSZ 圆盘相比，抛光的 8YSZ、4YSZ_P 和 8YSZ_P 圆盘以及未抛光的 8YSZ_R、4YSZ_PR 和 8YSZ_PR 圆盘的平均细胞黏附密度较低。在间接接触条件下，所有 YSZ 圆盘组的平均细胞黏附密度与细胞对照相似。抛光的 4YSZ_P 和 8YSZ_P 圆盘组、未抛光的 4YSZ_PR 和 8YSZ_PR 圆盘组以及 8YSZ_Pnp 的颗粒对照组的 Y 离子浓度高于其他组。细胞培养后，在抛光的 YSZ 圆盘上未检测到矿物质沉积。综合考虑细胞相容性、细胞黏附密度、Y 离子释放、矿物质沉积和光学透明度等多种因素，8YSZ 可能是颅窗应用的最佳候选材料。还需要进一步的研究来评估 YSZ 圆盘的长期透明度和生物相容性。
