Hierarchical Surface Pattern on Ni‐Free Ti‐Based Bulk Metallic Glass to Control Cell Interactions

Abstract

Ni‐free Ti‐based bulk metallic glasses (BMGs) are exciting materials for biomedical applications because of their outstanding biocompatibility and advantageous mechanical properties. The glassy nature of BMGs allows them to be shaped and patterned via thermoplastic forming (TPF). This work demonstrates the versatility of the TPF technique to create micro‐ and nano‐patterns and hierarchical structures on Ti40Zr10Cu34Pd14Sn2 BMG. Particularly, a hierarchical structure fabricated by a two‐step TPF process integrates 400 nm hexagonal close‐packed protrusions on 2.5 µm square protuberances while preserving the advantageous mechanical properties from the as‐cast material state. The correlations between thermal history, structure, and mechanical properties are explored. Regarding biocompatibility, Ti40Zr10Cu34Pd14Sn2 BMGs with four surface topographies (flat, micro‐patterned, nano‐patterned, and hierarchical‐structured surfaces) are investigated using Saos‐2 cell lines. Alamar Blue assay and live/dead analysis show that all tested surfaces have good cell proliferation and viability. Patterned surfaces are observed to promote the formation of longer filopodia on the edge of the cytoskeleton, leading to star‐shaped and dendritic cell morphologies compared with the flat surface. In addition to potential implant applications, TPF‐patterned Ti‐BMGs enable a high level of order and design flexibility on the surface topography, expanding the available toolbox for studying cell behavior on rigid and ordered surfaces.

Effect of Chemical Composition on the Thermoplastic Formability and Nanoindentation of Ti-Based Bulk Metallic Glasses

“…Cai et al [37] successfully developed a 300 µm square-well array pattern and a 5 µm squarehump array on the surface of Ti 40 Zr 10 Cu 34 Pd 14 Sn 2 using TPF, showcasing the potential for intricate patterning. Additionally, Cai et al [38] extended this work by fabricating a hierarchical structure on the surface of Ti 40 Zr 10 Cu 34 Pd 14 Sn 2 BMG through a two-step TPF process, effectively creating 400 nm protrusions atop 2.5 µm square humps. This marked the first instance of a Ti-based BMG achieving a layered structure with both micro-patterns and nano-patterns on the same surface.…”