Cell adhesion on NiTi thin film sputter-deposited meshes

Abstract

Scaffolds for tissue engineering enable the possibility to fabricate and form biomedical implants in vitro, which fulfill special functionality in vivo. In this study, free-standing Nickel–Titanium(NiTi) thin film mesheswere produced by means of magnetron sputter deposition.Meshes contained precisely defined rhombic holes in the size of 440 to 1309 μm2 and a strut width ranging from 5.3 to 9.2 μm. The effective mechanical properties of the microstructured superelastic NiTi thin film were examined by tensile testing. These results will be adapted for the design of the holes in the film. The influence of hole and strut dimensions on the adhesion of sheep autologous cells (CD133+) was studied after 24 h and after seven days of incubation. Optical analysis using fluorescence microscopy and scanning electron microscopy showed that cell adhesion depends on the structural parameters of the mesh. After 7 days in cell culture a large part of the mesh was covered with aligned fibrous material. Cell adhesion is particularly facilitated on meshes with small rhombic holes of 440 μm2 and a strut width of 5.3 μm. Our results demonstrate that free-standing NiTi thin film meshes have a promising potential for applicationsin cardiovascular tissue engineering, particularly for the fabrication of heart valves.

Challenges During Microstructural Analysis and Mechanical Testing of Small-Scale Pseudoelastic NiTi Structures

“…The resulting microstructures are typically characterized by considerably deformed grains, high dislocation densities (after cold work), and pronounced textures [4]. Physical vapor deposition (PVD) methods have emerged as an interesting alternative to these conventional processing routes; these PVD methods offer certain advantages, such as high purity (because samples are deposited in high vacuum), and because (pre-alloyed) targets can be carefully fine-tuned to the desired alloy composition [5][6][7]. Film morphologies, crystal growth, and textures can in principle be controlled using different substrate materials and subsequent heat treating conditions.…”

Shape Memory Alloy Thin Film Auxetic Structures

“…This leads to different stiffness of the overall design, which in turn leads to different material amount undergoing stress‐induced phase transformation. [ 47 ]…”

Properties of NiTi Shape Memory Alloy Micro-Foils Obtained by Pulsed-Current Sintering of Ni/Ti Foils

“…The demanding restrictions on the synthesis conditions are one of the main technological problems, where, for example, small content variation can significantly influence transformation properties [6,7]. In alloy production, vacuum melting methods are mainly used, and deposition methods are applied in the case of thin films [8], e.g., magnetron sputtering, pulsed laser deposition (PLD) [9,10], or biased target ion beam deposition (BTIBD) [11]. Sputtering methods are very effective for obtaining thin films of thickness up to few micrometers.…”