Pan Chang-Jiang, Dong Yun-Xiao, Zhang Yao-Yao, Nie Yu-Dong, Zhao Chang-Hong, Wang Yuan-Liang
Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400044, China.
J Orthop Sci. 2011 Jan;16(1):105-13. doi: 10.1007/s00776-010-0017-z. Epub 2011 Feb 4.
Bacterial infections associated with the use of biomaterials remain a great challenge for orthopedic surgery. The main purpose of the work discussed in this paper was to improve the antibacterial activity of a biomimetic calcium phosphate (CP) coating widely used in orthopedic biomaterials by incorporation of norvancomycin in the biomimetic process.
CP coating and CP coating containing norvancomycin were produced on a titanium alloy (Ti6Al4V) surface by a biomimetic process. The morphology, surface crystal structure, and concentrations of elements in the coatings were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX), respectively. The amount of norvancomycin and its release were investigated by UV-visible spectroscopy. MTT was used to investigate cell behavior. The morphology of adhered bacteria was observed by SEM. Antibacterial activity was expressed as inhibition zone by using Staphylococcus aureus (ATCC 25923) as model bacteria.
Results from SEM, EDX, and XRD revealed formation of a hydroxyapatite (HA) coating. The amount of antibiotic in the CP coating increased with increasing concentration of norvancomycin in the coating solution, followed by a plateau when the concentration of norvancomycin in the coating solution reached 600 mg/l. Approximately 2.16 μg norvancomycin per mg coating was co-precipitated with the CP layer onto titanium alloy discs when 600 mg/l norvancomycin coating solution was applied. The norvancomycin had a fast release profile followed by slow release. The MTT test of osteoblast cell cultures suggested that coatings containing norvancomycin did not cause any cytotoxicity compared with the CP coating and control titanium plate. The antibacterial activity test showed that the norvancomycin released from the coatings inhibited the growth of Staphylococcus aureus; more bacteria were found on the CP coating than on the norvancomycin-loaded coating.
A norvancomycin-loaded HA-like coating was successfully obtained on titanium surfaces. The norvancomycin incorporated had no negative effects on osteoblast cell behavior. The released norvancomycin results in excellent antibacterial activity of Ca-P coatings. Therefore, incorporation of norvancomycin can enhance antibacterial activity and the norvancomycin-loaded CP coating can be used to inhibit post-surgical infections in orthopaedics.
与生物材料使用相关的细菌感染仍然是骨科手术面临的巨大挑战。本文所讨论工作的主要目的是通过在仿生过程中加入去甲万古霉素来提高广泛应用于骨科生物材料的仿生磷酸钙（CP）涂层的抗菌活性。
通过仿生工艺在钛合金（Ti6Al4V）表面制备CP涂层和含去甲万古霉素的CP涂层。分别用扫描电子显微镜（SEM）、X射线衍射（XRD）和能量色散X射线光谱（EDX）对涂层的形态、表面晶体结构和元素浓度进行表征。用紫外可见光谱研究去甲万古霉素的含量及其释放情况。用MTT法研究细胞行为。用SEM观察黏附细菌的形态。以金黄色葡萄球菌（ATCC 25923）为模型菌，将抗菌活性表示为抑菌圈。
SEM、EDX和XRD结果显示形成了羟基磷灰石（HA）涂层。CP涂层中抗生素的含量随涂层溶液中去甲万古霉素浓度的增加而增加，当涂层溶液中去甲万古霉素浓度达到600 mg/l时达到平台期。当使用600 mg/l去甲万古霉素涂层溶液时，每毫克涂层中约2.16 μg去甲万古霉素与CP层共沉淀在钛合金圆盘上。去甲万古霉素呈现快速释放后缓慢释放的特征。成骨细胞培养的MTT试验表明，与CP涂层和对照钛板相比，含去甲万古霉素的涂层未引起任何细胞毒性。抗菌活性试验表明，涂层释放的去甲万古霉素抑制了金黄色葡萄球菌的生长；在CP涂层上发现的细菌比载有去甲万古霉素的涂层上更多。
在钛表面成功获得了载有去甲万古霉素的类HA涂层。掺入的去甲万古霉素对成骨细胞行为没有负面影响。释放的去甲万古霉素使钙磷涂层具有优异的抗菌活性。因此，掺入去甲万古霉素可增强抗菌活性，载有去甲万古霉素的CP涂层可用于抑制骨科手术后感染。
