Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, UCLA School of Dentistry, Los Angeles, CA 90095-1668, USA.
Department of Orthodontics, School of Dentistry, Aichi-Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi 464-8650, Japan.
Int J Mol Sci. 2020 Jan 23;21(3):738. doi: 10.3390/ijms21030738.
Titanium (Ti) is an osteoconductive material that is routinely used as a bulk implant to fix and restore bones and teeth. This study explored the effective use of Ti as a bone engineering scaffold. Challenges to overcome were: (1) difficult liquid/cell infiltration into Ti microfiber scaffolds due to the hydrophobic nature of Ti; and (2) difficult cell attachment on thin and curved Ti microfibers. A recent discovery of UV-photofunctionalization of Ti prompted us to examine its effect on Ti microfiber scaffolds. Scaffolds in disk form were made by weaving grade 4 pure Ti microfibers (125 µm diameter) and half of them were acid-etched to roughen the surface. Some of the scaffolds with original or acid-etched surfaces were further treated by UV light before cell culture. Ti microfiber scaffolds, regardless of the surface type, were hydrophobic and did not allow glycerol/water liquid to infiltrate, whereas, after UV treatment, the scaffolds became hydrophilic and immediately absorbed the liquid. Osteogenic cells from two different origins, derived from the femoral and mandibular bone marrow of rats, were cultured on the scaffolds. The number of cells attached to scaffolds during the early stage of culture within 24 h was 3-10 times greater when the scaffolds were treated with UV. The development of cytoplasmic projections and cytoskeletal, as well as the expression of focal adhesion protein, were exclusively observed on UV-treated scaffolds. Osteoblastic functional phenotypes, such as alkaline phosphatase activity and calcium mineralization, were 2-15 times greater on UV-treated scaffolds, with more pronounced enhancement on acid-etched scaffolds compared to that on the original scaffolds. These effects of UV treatment were associated with a significant reduction in atomic carbon on the Ti microfiber surfaces. In conclusion, UV treatment of Ti microfiber scaffolds tunes their physicochemical properties and effectively enhances the attachment and function of osteoblasts, proposing a new strategy for bone engineering.
钛（Ti）是一种骨诱导材料，通常用作固定和修复骨骼和牙齿的块状植入物。本研究探索了 Ti 作为骨工程支架的有效用途。需要克服的挑战有：（1）Ti 的疏水性导致难以将液体/细胞渗透到 Ti 微纤维支架中；（2）难以将细胞附着在薄而弯曲的 Ti 微纤维上。Ti 的 UV 光功能化的最新发现促使我们研究其对 Ti 微纤维支架的影响。通过编织 4 级纯 Ti 微纤维（直径 125 µm）制成圆盘状支架，其中一半用酸蚀处理以粗糙化表面。原始或酸蚀表面的一些支架在细胞培养之前进一步用 UV 光处理。无论表面类型如何，Ti 微纤维支架都是疏水性的，不允许甘油/水液体渗透，而经过 UV 处理后，支架变得亲水并立即吸收液体。来自大鼠股骨和下颌骨髓的两种不同来源的成骨细胞在支架上培养。在培养的最初 24 小时内，用 UV 处理的支架上附着的细胞数量是未经处理的支架的 3-10 倍。在用 UV 处理的支架上仅观察到细胞质突起和细胞骨架的发育以及黏着斑蛋白的表达。在用 UV 处理的支架上，碱性磷酸酶活性和钙矿化等成骨细胞功能表型是未经处理的支架的 2-15 倍，在用酸蚀支架上的增强比在原始支架上更为明显。UV 处理的这种效果与 Ti 微纤维表面的原子碳显著减少有关。总之，UV 处理 Ti 微纤维支架可调整其物理化学性质，并有效增强成骨细胞的附着和功能，为骨工程提出了一种新策略。
