Department of Materials Engineering, University of British Columbia, 309 - 6350 Stores Road, Vancouver, BC, V6T 1Z4, Canada.
Biomaterials. 2010 Dec;31(36):9519-26. doi: 10.1016/j.biomaterials.2010.08.035.
Prevention of implant-associated infections has been one of the main challenges in orthopaedic surgery. This challenge is further complicated by the concern over the development of antibiotic resistance as a result of using traditional antibiotics for infection prophylaxis. The objective of this study was to develop a technique that enables the loading and local delivery of a unique group of cationic antimicrobial peptides (AMP) through implant surfaces. A thin layer of micro-porous calcium phosphate (CaP) coating was processed by electrolytic deposition onto the surface of titanium as the drug carrier. The broad spectrum AMP Tet213 (KRWWKWWRRC) was selected and loaded onto the CaP coating. SEM, XRD and FTIR analyses confirmed the CaP coating to be micro-porous octacalcium phosphate. By using a luminescence spectrometer technique, it was demonstrated that a 7 μm thick porous CaP coating could load up to 9 μg of AMP/cm² using a simple soaking technique. The drug-loaded CaP coating (CaP-Tet213) was not cytotoxic for MG-63 osteoblast-like cells. The CaP-Tet213 implants had antimicrobial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria with 10⁶-fold reductions of both bacterial strains within 30 min as assessed by measuring colony-forming units (CFU). Repeated CFU assays on the same CaP-Tet213 specimen demonstrated retention of antimicrobial activity by the CaP-Tet213 surfaces through four test cycles. The susceptibility of bacteria to the CaP-Tet213 surfaces was also evaluated by assessing the inhibition of luminescence of P. aeruginosa containing a luxCDABE cassette at 4 h and 24 h with ∼92% and ∼77% inhibition of luminescence, respectively. It was demonstrated that CaP-Tet213 was a more efficient antimicrobial coating than CaP-MX226, CaP-hLF1-11 or CaP-tobramycin following incubation of CaP implants with equimolar concentrations of Tet213, the commercially developed antimicrobial peptide MX-226, hLF1-11 or tobramycin. A device coated with CaP-Tet213 could be a potential solution for the prevention of the peri-implant infection in orthopaedics.
预防植入物相关感染一直是骨科手术面临的主要挑战之一。由于传统抗生素在预防感染方面的应用，导致抗生素耐药性的出现，这使得这一挑战更加复杂。本研究的目的是开发一种技术，使独特的阳离子抗菌肽（AMP）能够通过植入物表面加载和局部输送。通过电解沉积在钛表面处理一层薄的微孔磷酸钙（CaP）涂层作为药物载体。广谱 AMP Tet213（KRWWKWWRRC）被选择并加载到 CaP 涂层上。SEM、XRD 和 FTIR 分析证实 CaP 涂层为微孔八钙磷酸盐。通过使用荧光分光光度计技术，证明 7 μm 厚的多孔 CaP 涂层可以通过简单的浸泡技术加载高达 9 μg AMP/cm²。负载药物的 CaP 涂层（CaP-Tet213）对 MG-63 成骨样细胞没有细胞毒性。CaP-Tet213 植入物对革兰氏阳性（金黄色葡萄球菌）和革兰氏阴性（铜绿假单胞菌）细菌均具有抗菌活性，在 30 分钟内两种细菌的菌落形成单位（CFU）减少了 10⁶ 倍。对同一 CaP-Tet213 标本进行重复 CFU 检测，证明 CaP-Tet213 表面通过四个测试循环保留了抗菌活性。还通过评估含有 luxCDABE 盒的铜绿假单胞菌的发光抑制来评估细菌对 CaP-Tet213 表面的敏感性，在 4 小时和 24 小时时，发光抑制率分别约为 92%和 77%。结果表明，与 CaP-MX226、CaP-hLF1-11 或 CaP-妥布霉素相比，CaP-Tet213 是一种更有效的抗菌涂层，在与等摩尔浓度的 Tet213、市售抗菌肽 MX-226、hLF1-11 或妥布霉素孵育后，CaP 植入物的抗菌效果更好。涂有 CaP-Tet213 的装置可能是预防骨科植入物周围感染的一种潜在解决方案。
