Department of Applied Science and Technology , Politecnico di Torino , C.so Duca degli Abruzzi 24 , 10129 Turin , Italy.
Istituto Italiano di Tecnologia, Smart Bio-Interfaces , Viale Rinaldo Piaggio 34 , 56025 Pontedera , Pisa , Italy.
ACS Appl Mater Interfaces. 2019 Jan 9;11(1):449-456. doi: 10.1021/acsami.8b20728. Epub 2018 Dec 21.
Mesoporous zinc oxide (ZnO) scaffolds coated with drop-cast graphene oxide (GO) flakes are proposed to be a novel bilayer system featuring bioactivity, biocompatibility, and promising loading/release properties for controlled drug-delivery systems. The high-surface-area ZnO scaffolds show clear apatite deposition, but their particular surface chemistry and topography prevent the formation of a continuous coating, resulting in micrometric crystalline apatite aggregates after 28 days in simulated body fluid (SBF). When gentamicin sulfate (GS) is considered as a model molecule, pure ZnO scaffolds also show functional GS loading efficiency, with fast in vitro release kinetics driven by a simple diffusion mechanism. Strikingly, the bioactivity and GS delivery properties of mesoporous ZnO are efficiently triggered by drop-casting GO flakes atop the mesoporous scaffold surface. The resulting ZnO@GO bilayer scaffolds show the formation of a uniform apatite coating after 28 days in SBF and demonstrate a biocompatible behavior, supporting the culture of SaOS-2 osteoblast-like cells. Moreover, the GO coating also leads to a barrier-layer effect, preventing fast GS release, particularly in the short time range. This barrier effect, coupled with the existence of nanopores within the GO structure, sieves drug molecules from the mesoporous ZnO matrix and allows for a delayed release of the GS molecule. We, thus, demonstrated a new-generation ZnO@GO bilayer system as effective multifunctional and biocompatible scaffold for bone tissue engineering.
介孔氧化锌 (ZnO) 支架表面涂覆了滴铸氧化石墨烯 (GO) 薄片，形成了一种具有生物活性、生物相容性和有前途的载药/释药性能的新型双层系统，适用于控制药物释放系统。高表面积的 ZnO 支架显示出明显的磷灰石沉积，但由于其特殊的表面化学性质和形貌，阻止了连续涂层的形成，导致在模拟体液 (SBF) 中培养 28 天后形成了微米级的结晶磷灰石聚集体。当硫酸庆大霉素 (GS) 被视为模型分子时，纯 ZnO 支架也表现出功能性的 GS 负载效率，具有快速的体外释放动力学，这是由简单的扩散机制驱动的。引人注目的是，将 GO 薄片滴铸在介孔支架表面上，可以有效地触发介孔 ZnO 的生物活性和 GS 输送性能。在 SBF 中培养 28 天后，所得的 ZnO@GO 双层支架形成了均匀的磷灰石涂层，并表现出生物相容性，支持 SaOS-2 成骨样细胞的培养。此外，GO 涂层还具有阻挡层效应，可防止 GS 的快速释放，尤其是在短时间范围内。这种阻挡效应，再加上 GO 结构内存在的纳米孔，将药物分子从介孔 ZnO 基质中筛出，并允许 GS 分子的延迟释放。因此，我们展示了一种新一代的 ZnO@GO 双层系统，作为用于骨组织工程的有效多功能和生物相容的支架。
