Division of Bioengineering, National University of Singapore, Singapore.
Biomed Mater. 2012 Feb;7(1):015001. doi: 10.1088/1748-6041/7/1/015001. Epub 2011 Dec 9.
The time required for osseointegration with a metal implant having a smooth surface ranges from three to six months. We hypothesized that biomimetic coating surfaces with poly(lactic-co-glycolic acid) (PLGA)/collagen fibers and nano-hydroxyapatite (n-HA) on the implant would enhance the adhesion of mesenchymal stem cells. Therefore, this surface modification of dental and bone implants might enhance the process of osseointegration. In this study, we coated PLGA or PLGA/collagen (50:50 w/w ratio) fiber on Ti disks by modified electrospinning for 5 s to 2 min; after that, we further deposited n-HA on the fibers. PLGA fibers of fiber diameter 0.957 ± 0.357 µm had a contact angle of 9.9 ± 0.3° and PLGA/collagen fibers of fiber diameter 0.378 ± 0.068 µm had a contact angle of 0°. Upon n-HA incorporation, all the fibers had a contact angle of 0° owing to the hydrophilic nature of n-HA biomolecule. The cell attachment efficiency was tested on all the scaffolds for different intervals of time (10, 20, 30 and 60 min). The alkaline phosphatase activity, cell proliferation and mineralization were analyzed on all the implant surfaces on days 7, 14 and 21. Results of the cell adhesion study indicated that the cell adhesion was maximum on the implant surface coated with PLGA/collagen fibers deposited with n-HA compared to the other scaffolds. Within a short span of 60 min, 75% of the cells adhered onto the mineralized PLGA/collagen fibers. Similarly by day 21, the rate of cell proliferation was significantly higher (p ⩽ 0.05) on the mineralized PLGA/collagen fibers owing to enhanced cell adhesion on these fibers. This enhanced initial cell adhesion favored higher cell proliferation, differentiation and mineralization on the implant surface coated with mineralized PLGA/collagen fibers.
具有光滑表面的金属植入物的骨整合时间范围为 3 至 6 个月。我们假设在植入物表面涂有聚乳酸-共-羟基乙酸（PLGA）/胶原纤维和纳米羟基磷灰石（n-HA）的仿生涂层表面会增强间充质干细胞的黏附。因此，这种牙和骨植入物的表面修饰可能会增强骨整合过程。在这项研究中，我们通过改良的静电纺丝在 Ti 盘上涂覆 PLGA 或 PLGA/胶原（50:50 w/w 比）纤维 5 秒至 2 分钟；之后，我们在纤维上进一步沉积 n-HA。纤维直径为 0.957 ± 0.357 µm 的 PLGA 纤维的接触角为 9.9 ± 0.3°，纤维直径为 0.378 ± 0.068 µm 的 PLGA/胶原纤维的接触角为 0°。加入 n-HA 后，由于 n-HA 生物分子的亲水性，所有纤维的接触角均为 0°。在不同的时间段（10、20、30 和 60 min）对所有支架进行细胞附着效率测试。在第 7、14 和 21 天，在所有植入物表面分析碱性磷酸酶活性、细胞增殖和矿化。细胞黏附研究的结果表明，与其他支架相比，涂有 PLGA/胶原纤维并沉积 n-HA 的植入物表面的细胞黏附率最高。在短短的 60 分钟内，有 75%的细胞黏附在矿化的 PLGA/胶原纤维上。同样，在第 21 天，由于这些纤维上的细胞黏附增强，细胞增殖速度显著更高（p ⩽ 0.05）。这种初始细胞黏附的增强有利于在涂覆有矿化 PLGA/胶原纤维的植入物表面上实现更高的细胞增殖、分化和矿化。
