Colon Gabriel, Ward Brian C, Webster Thomas J
Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907-2022, USA.
J Biomed Mater Res A. 2006 Sep 1;78(3):595-604. doi: 10.1002/jbm.a.30789.
Many engineers and surgeons trace implant failure to poor osseointegration (or the bonding of an orthopedic implant to juxtaposed bone) and/or bacteria infection. By using novel nanotopographies, researchers have shown that nanostructured ceramics, carbon fibers, polymers, metals, and composites enhance osteoblast adhesion and calcium/phosphate mineral deposition. However, the function of bacteria on materials with nanostructured surfaces remains largely uninvestigated. This is despite the fact that during normal surgical insertion of an orthopedic implant, bacteria from the patient's own skin and/or mucosa enters the wound site. These bacteria (namely, Staphylococcus epidermidis) irreversibly adhere to an implant surface while various physiological stresses induce alterations in the bacterial growth rate leading to biofilm formation. Because of their integral role in determining the success of orthopedic implants, the objective of this in vitro study was to examine the functions of (i) S. epidermidis and (ii) osteoblasts (or bone-forming cells) on ZnO and titania (TiO(2)), which possess nanostructured compared to microstructured surface features. ZnO is a well-known antimicrobial agent and TiO(2) readily forms on titanium once implanted. Results of this study provided the first evidence of decreased S. epidermidis adhesion on ZnO and TiO(2) with nanostructured when compared with microstructured surface features. Moreover, compared with microphase formulations, results of this study showed increased osteoblast adhesion, alkaline phosphatase activity, and calcium mineral deposition on nanophase ZnO and TiO(2). In this manner, this study suggests that nanophase ZnO and TiO(2) may reduce S. epidermidis adhesion and increase osteoblast functions necessary to promote the efficacy of orthopedic implants.
许多工程师和外科医生将植入物失效归因于骨整合不良（即骨科植入物与相邻骨骼的结合）和/或细菌感染。通过使用新型纳米拓扑结构，研究人员表明，纳米结构的陶瓷、碳纤维、聚合物、金属和复合材料可增强成骨细胞粘附以及钙/磷酸盐矿物质沉积。然而，细菌在具有纳米结构表面的材料上的作用在很大程度上仍未得到研究。尽管在骨科植入物的正常手术插入过程中，患者自身皮肤和/或粘膜中的细菌会进入伤口部位，但情况依然如此。这些细菌（即表皮葡萄球菌）不可逆地粘附在植入物表面，同时各种生理应激会导致细菌生长速率发生变化，从而形成生物膜。由于它们在决定骨科植入物成功与否方面起着不可或缺的作用，因此本体外研究的目的是检验（i）表皮葡萄球菌和（ii）成骨细胞（即骨形成细胞）在氧化锌（ZnO）和二氧化钛（TiO₂）上的功能，与具有微观结构表面特征相比，它们具有纳米结构。ZnO是一种众所周知的抗菌剂，TiO₂在植入后很容易在钛上形成。本研究结果首次证明，与具有微观结构表面特征相比，具有纳米结构的ZnO和TiO₂上表皮葡萄球菌的粘附减少。此外，与微相配方相比，本研究结果表明，纳米相ZnO和TiO₂上的成骨细胞粘附、碱性磷酸酶活性和钙矿物质沉积增加。通过这种方式，本研究表明，纳米相ZnO和TiO₂可能会减少表皮葡萄球菌的粘附，并增加促进骨科植入物疗效所需的成骨细胞功能。
