Data from: The relationship between substrate morphology and biological performances of nano-silver-loaded dopamine coatings on the titanium surfaces

Biomedical device-associated infection(BAI) and lack of osseointegration are the main causes of implant failure. Therefore, it is imperative for implant not only to depress microbial activity and biofilm colonization but also to prompt osteoblast functions and osseointegration. As part of the coating development for implants, the interest of in vitro studies on the interaction between implant substrate morphology and biological performances is growing. In this study, by harnessing the adhesion and reactivity of bioinspired polydopamine, nano-silver were successfully anchored onto micro/nanoporous as well as smooth titanium surfaces to analyze the effect of substrate morphology on biological performances of the coatings. Compared with smooth surface, small size of nano-Ag and high Ag content was found on the micro/nanoporous surface. More mineralization happened on the coating on micro/nanoporous structure than on smooth surface, which led to a more rapid decrease of Ag release from micro/nanoporous surface. Antimicrobial tests indicated that both surfaces with resulting coating inhibit microbial colonization on them and growth around them, indicating that the coating eliminates the shortcoming of porous structure which render the implant extremely susceptible to BAI. Besides, the multiple osteoblast responses of nano-Ag-loaded dopamine coatings on both surfaces, i.e. attachment, proliferation and differentiation, have deteriorated, however the mineralized surfaces of these coatings stimulated osteoblast proliferation and differentiation, especially for the micro/nanoporous surface. So the resulting coatings on micro/nanoporous substratum may not only reduce the risk of infection but also facilitate mineralization during the early post-operative period and then promote osseointegration due to good osteoblast-biocompatibility of the mineralized surface. These results highlight the influence of the substrate morphology on the biological performances of implant coating.

医疗器械相关感染(BAI, Biomedical device-associated infection)与骨整合(osseointegration)缺失是导致种植体失效的两大主要诱因。因此，种植体不仅需要抑制微生物活性与生物膜(biofilm)定植，还需促成成骨细胞(osteoblast)功能与骨整合。作为种植体涂层开发的重要组成部分，探究种植体基底形貌与生物学性能之间相互作用的体外研究愈发受到学界关注。本研究借助仿生聚多巴胺(bioinspired polydopamine)的粘附性与反应活性，成功将纳米银(nano-silver)锚定至微纳多孔(micro/nanoporous)与光滑钛表面，以此分析基底形貌对涂层生物学性能的影响。相较于光滑表面，微纳多孔表面负载的纳米银粒径更小、银含量更高。微纳多孔结构涂层的矿化程度高于光滑表面涂层，进而使得微纳多孔表面的银离子释放速率更快衰减。抗菌实验结果显示，两种表面负载所得涂层均可抑制微生物在其表面及周围定植与增殖，表明该涂层弥补了多孔结构易引发医疗器械相关感染的固有缺陷。此外，尽管两种表面负载纳米银的多巴胺涂层对成骨细胞的多项应答反应（包括黏附、增殖与分化）均出现了一定程度的减弱，但经矿化处理的涂层表面可促进成骨细胞增殖与分化，其中微纳多孔表面的效果尤为显著。综上，微纳多孔基底上制备的所得涂层不仅可降低感染风险，还能在术后早期促进矿化进程；同时凭借矿化表面优异的成骨细胞生物相容性，最终推动骨整合。本研究结果凸显了基底形貌对种植体涂层生物学性能的调控作用。