He Tao, Zhang Ying, Lai Alvin C K, Chan Vincent
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, 117602, Singapore.
Biomed Mater. 2015 Jan 29;10(1):015015. doi: 10.1088/1748-6041/10/1/015015.
Functionalization of a biomaterial surface with adhesive ligands is an effective way to promote specific cell adhesion. Ideally, biomaterial for applications in biomedical implants should simultaneously promote host cell adhesion and inhibit bacterial adhesion. Currently, little attention has been paid to the design of antimicrobial biomaterial with selective adhesiveness towards only targeted cells or tissues. In this study, the role of two typical adhesive ligands on the bioadhesion functions of a model antimicrobial film was elucidated. First, an adhesive ligand including an RGD peptide or collagen (CL) was chemically coupled to an antimicrobial polymeric multilayer composed of dextran sulfate (DS) and chitosan (CS). It was demonstrated that the density of RGD and CL immobilized on the DS/CS multilayer ranges between 4 to 137 ng cm(-2) and 100 to 1000 ng cm(-2), respectively. Then the effect of immobilized RGD or CL on both bacterial and fibroblast adhesion was investigated. By determining the density and morphology of adherent fibroblast on a DS/CS multilayer with or without an adhesive ligand, it was shown that RGD or CL effectively promoted fibroblast adhesion and proliferation in a concentration-dependent manner. Interestingly, the type of adhesive ligands imposed distinct effects in bacterial adhesion. Immobilized RGD did not enhance Staphylococcus aureus and Escherichia coli adhesion on DS/CS multilayers under all concentrations. In contrast, CL triggered significant S. aureus adhesion on DS/CS multilayers even at low surface concentration and when fibroblast adhesion was absent. Moreover, the detachment forces of individual S. aureus on CL coated DS/CS multilayers probed by atomic force microscopy (AFM) was 3 times and 20 times higher than that on the control substrate and on unmodified DS/CS multilayers, respectively. Interestingly, the lowest detachment force of E. coli was found on the CL coated DS/CS multilayers. This study demonstrated the possibility of engineering an antimicrobial multilayer coating with tailored adhesive properties towards specific cell types for potential applications in biomedical implants.
用黏附配体对生物材料表面进行功能化修饰是促进特定细胞黏附的有效方法。理想情况下，用于生物医学植入物的生物材料应同时促进宿主细胞黏附并抑制细菌黏附。目前，对于仅对靶向细胞或组织具有选择性黏附性的抗菌生物材料的设计关注较少。在本研究中，阐明了两种典型黏附配体对模型抗菌膜生物黏附功能的作用。首先，将包含RGD肽或胶原蛋白（CL）的黏附配体化学偶联到由硫酸葡聚糖（DS）和壳聚糖（CS）组成的抗菌聚合物多层膜上。结果表明，固定在DS/CS多层膜上的RGD和CL的密度分别在4至137 ng cm⁻²和100至1000 ng cm⁻²之间。然后研究了固定化的RGD或CL对细菌和成纤维细胞黏附的影响。通过测定有或没有黏附配体的DS/CS多层膜上贴壁成纤维细胞的密度和形态，结果表明RGD或CL以浓度依赖的方式有效促进了成纤维细胞的黏附和增殖。有趣的是，黏附配体的类型对细菌黏附产生了不同的影响。在所有浓度下，固定化的RGD均未增强金黄色葡萄球菌和大肠杆菌在DS/CS多层膜上的黏附。相反，即使在低表面浓度且不存在成纤维细胞黏附的情况下，CL也会引发金黄色葡萄球菌在DS/CS多层膜上的显著黏附。此外，通过原子力显微镜（AFM）探测，单个金黄色葡萄球菌在CL包被的DS/CS多层膜上的脱离力分别比在对照底物和未修饰的DS/CS多层膜上高3倍和20倍。有趣的是，在CL包被的DS/CS多层膜上发现大肠杆菌的最低脱离力。本研究证明了设计一种对特定细胞类型具有定制黏附特性的抗菌多层涂层用于生物医学植入物潜在应用的可能性。
