ABSTRACT

A coating on the surfaces of metallic implants to promote bone cell integration as well as prevent infection is highly desired for orthopedic surgeries. A novel antibacterial peptide was grafted onto an osteoinductive coating and the modified coating was tested for its antibacterial properties and biocompatibility with bone cells in vitro. A layer of chitosan hydrogel was chemically attached to the surface of a medical-grade titanium alloy and a novel non-RGD peptide (H-ckrwwkwirw-NH₂) was grafted on top of the coating through chemical cross-linking. The composite layer was tested for its surface wettability (contact angle), composition (energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy), antibacterial property, and bone cell biocompatibility. The successful grafting of the peptide onto the coating was confirmed by the increase of contact angle and nitrogen content (both p < .05) on the surface due to the presence of the hydrophobic amino acids. The modified coating successfully reduced the growth of Gram negative and positive (E. coli and S. aureus) bacteria by 74.2% and 52.4%, respectively (p < .01). The coating did not show any sign of cytotoxicity and unexpectedly improved osteoblast proliferation and mineralization compared to unmodified samples (all p < .01). An antimicrobial peptide successfully grafted onto the chitosan coating to enhance its bactericidal function. This non-RGD peptide, after chemical modification, not only preserved its bactericidal activity but also improved the biocompatibility of the coating.

摘要

骨外科非常需要金属植入物表面的涂层以促进骨细胞整合并防止感染。将新型抗菌肽移植到骨诱导涂层上，并在体外测试改性涂层的抗菌性能和与骨细胞的生物相容性。将壳聚糖水凝胶层化学连接到医用级钛合金和新型非RGD肽（H-ckrwwkwirw-NH ₂）通过化学交联接枝到涂层的顶部。测试该复合层的表面润湿性（接触角），组成（能量分散X射线能谱和X射线光电子能谱），抗菌性能和骨细胞生物相容性。由于存在疏水性氨基酸，表面上的接触角和氮含量增加（均为p <.05），从而证实了肽成功嫁接到涂层上。改良的涂层成功地将革兰氏阴性和阳性（大肠杆菌和金黄色葡萄球菌）细菌的生长分别减少了74.2％和52.4％（p<.01）。与未修饰的样品相比，涂层没有显示出任何细胞毒性迹象，并且出乎意料地改善了成骨细胞的增殖和矿化作用（所有p <.01）。一种抗菌肽已成功嫁接到壳聚糖涂层上，以增强其杀菌功能。经过化学修饰后，这种非RGD肽不仅保留了其杀菌活性，而且还改善了涂层的生物相容性。