Supplementary information files for Physico-chemical characterisation of Ti-Nb-Sn alloys surfaces and their osteogenic properties

Supplementary information files for Physico-chemical characterisation of Ti-Nb-Sn alloys surfaces and their osteogenic properties<br>mplanted tissue engineering devices interact with the host tissue through their surface in the first instance. Surface chemistry triggers cell activities that stimulate bone tissue-formation mechanisms for osteoblast maturation. In this work, the bioactivity of binary Ti-40Nb and Ti-10Sn and ternary Ti-10Nb-5Sn alloys, candidates for bioengineering applications, has been studied on their surface with a view to establish their osteogenic potential compared to that of c.p. Ti. Cellular population growth was used to assess proliferative and differentiative phenotypes (via protein and Alkaline Phosphatase markers), coupled with gene expression (i.e. Runx2 and OCN) to confirm maturation. The results show that Sn-containing alloys support cell bioactivity, increase metabolic activity (i.e. metabolites content) that indicate their preferred glycolytic pathway, promote cell attachment, differentiation and osteoblast maturation. Ti-40Nb, although also non-cytotoxic, retards osteoblastic differentiation and maturation. To elucidate the features that underpin this difference, their physical (i.e. wettability, electrical state near the surface) and chemical properties (i.e. oxide layer thickness and composition) were analysed independently from topology and roughness. It was concluded that composition (esp. TiO2 % content) is a more important factor than wettability and oxide layer thickness, and that although a negatively-charged surface (represented by the surface ζ potential) was preferential for cell bioactivity given its protein-adsorption readiness, its magnitude was not a defining cause.<br>

钛铌锡合金表面理化表征（Physico-chemical characterisation）及其成骨特性（osteogenic properties）辅助信息文件
植入式组织工程器械首先通过其表面与宿主组织（host tissue）发生相互作用。表面化学（surface chemistry）特性可启动细胞活动，进而激活骨组织形成机制，推动成骨细胞（osteoblast）成熟。本研究针对可用于生物工程应用（bioengineering applications）的二元Ti-40Nb、Ti-10Sn合金与三元Ti-10Nb-5Sn合金，以纯钛（c.p. Ti）为对照，从表面层面探究其成骨潜能（osteogenic potential），评估其生物活性。研究通过细胞群体生长情况评估细胞的增殖与分化表型（proliferative and differentiative phenotypes），借助蛋白标志物与碱性磷酸酶（Alkaline Phosphatase）标志物完成评估，并结合基因表达（gene expression）水平（即Runx2与骨钙素（Osteocalcin, OCN））验证成骨细胞成熟度。研究结果表明，含锡合金可维持细胞生物活性，提升代谢活性（metabolic activity）（即代谢物含量（metabolites content）），该活性提示其偏好采用糖酵解途径（glycolytic pathway），同时可促进细胞黏附（cell attachment）、分化及成骨细胞成熟。Ti-40Nb合金虽无细胞毒性（cytotoxic），但会延缓成骨细胞分化（osteoblastic differentiation）与成熟。为阐明造成该差异的核心特征，本研究独立于表面拓扑结构（topology）与粗糙度（roughness），分别分析了合金的物理特性（即润湿性（wettability）、表面附近电状态）与化学特性（即氧化层（oxide layer）厚度与成分）。最终得出结论：合金成分（尤其是二氧化钛（TiO₂）含量占比）比润湿性与氧化层厚度更为关键；尽管带负电的表面（以表面Zeta电位（ζ potential）为表征）因具备更强的蛋白质吸附能力，更利于细胞生物活性，但其电位幅值并非决定细胞行为的核心因素。