Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan, 106.
Graduate Institute of Biochemical and Biomedical Engineering, National Taipei University of Technology, Taipei, Taiwan, 106.
J Mater Sci Mater Med. 2017 Aug 17;28(9):140. doi: 10.1007/s10856-017-5951-2.
The surface of medical implant alloy Ti-6Al-4V was chemically modified to allow it to covalently bond with collagen/PVA nanofibers. These nanofibers were successfully attached to the Ti-6Al-4V surface in three different morphologies: randomly oriented high-density fiber, COL(H); randomly oriented low-density fiber, COL(L); and aligned high-density fiber, COL(A). The effects of the morphology of these covalently-bound collagen nanofibers on the growth and differentiation of osteoblasts were studied for 21 days. The low-density nanofibers covered approximately 80% of the Ti64 surface, while the high-density nanofibers covered nearly 100%. These covalently attached fibrous coatings remained attached to the metal surface after 3 weeks of cell culture. In the first week the aligned fibers of COL(A) allowed the osteoblasts to stretch and elongate in the direction of the fibers. This directional elongation was not seen in the cells on the randomly-oriented samples. Cells proliferated and differentiated on all three surfaces over time. By the end of the test, the amount of type I collagen secreted by the cells on COL(H) was the highest, while the degree of mineralization was highest on COL(A) among the three samples (p < 0.05). Different nanofiber morphologies changed the cell morphology and the secretion of cellular products. The mechanisms remained to be investigated. The surface of medical implant alloy Ti-6Al-4V was chemically modified to allow it to covalently bond with collagen/PVA nanofibers. The SEM micrographs in the top row show the random and aligned morphology of the collagen-PVA nanofibers. The nanofibers on COL(A) were aligned in the general direction indicated by the arrow. The second row are images from EDX titanium element mapping. The location of the titanium elements are shown as bright dots. The low-density nanofibers, COL(L), covered approximately 80% of the Ti64 surface, while the high-density nanofibers, COL(H) and COL(A), covered nearly 100%. All three surfaces demonstrated good biocompatibility for the cultured osteoblasts. The fiber alignment seemed to have an effect on early cellular morphology (day 7), collagen secretion and calcium deposition, while the density of the fibers seemed to have no significant effect on cell behavior. SEM micrographs of osteoblasts after 7 and 14 days of cell culture are shown in the third and fourth rows. The surface of COL(L) has more cell-free spots indicated by (*) on day 7 as other two surfaces were covered by cells. The nanofibers could no longer be observed and were covered with mineralized granules (circles) after 14 days of cell culture. The cells appear stretched out on the mineralized granules.
将医用植入合金 Ti-6Al-4V 的表面进行化学修饰，使其能够与胶原/PVA 纳米纤维共价结合。这些纳米纤维成功地以三种不同形态附着在 Ti-6Al-4V 表面：无规取向高密度纤维 COL(H)；无规取向低密度纤维 COL(L)；和取向高密度纤维 COL(A)。研究了这些共价结合胶原纳米纤维的形态对成骨细胞生长和分化的影响，培养时间为 21 天。低密度纳米纤维覆盖了 Ti64 表面的约 80%，而高密度纳米纤维覆盖了近 100%。这些共价附着的纤维涂层在细胞培养 3 周后仍附着在金属表面上。在第一周，COL(A)中的取向纤维允许成骨细胞沿纤维方向伸展和伸长。在无规取向样品上的细胞中没有观察到这种定向伸长。随着时间的推移，所有三种表面上的细胞都增殖和分化。到测试结束时，细胞在 COL(H)上分泌的 I 型胶原最多，而在三种样品中 COL(A)的矿化程度最高（p<0.05）。不同的纳米纤维形态改变了细胞形态和细胞产物的分泌。其机制仍有待研究。对医用植入合金 Ti-6Al-4V 的表面进行化学修饰，使其能够与胶原/PVA 纳米纤维共价结合。顶行的 SEM 显微照片显示了胶原-PVA 纳米纤维的无规和取向形态。COL(A)上的纳米纤维沿箭头所示的大致方向取向。第二行是 EDX 钛元素映射的图像。钛元素的位置显示为亮点。低密度纳米纤维 COL(L)覆盖了 Ti64 表面的约 80%，而高密度纳米纤维 COL(H)和 COL(A)覆盖了近 100%。所有三种表面都表现出良好的成骨细胞生物相容性。纤维取向似乎对早期细胞形态（第 7 天）、胶原分泌和钙沉积有影响，而纤维密度似乎对细胞行为没有显著影响。第 3 行和第 4 行显示了细胞培养 7 天和 14 天后成骨细胞的 SEM 显微照片。第 7 天，COL(L)表面有更多的无细胞斑点（*），而其他两个表面都被细胞覆盖。培养 14 天后，纳米纤维无法再观察到，被矿化颗粒（圆圈）覆盖。细胞似乎在矿化颗粒上伸展。
