title: Interface of nanoparticle-coated electropolished stents.
abstract: Nanostructures entail a high potential for improving implant surfaces, for instance, in stent applications. The electrophoretic deposition of laser-generated colloidal nanoparticles is an appropriate tool for creating large-area nanostructures on surfaces. Until now, the bonding and characteristics of the interface between deposited nanoparticles and the substrate surface has not been known. It is investigated using X-ray photoelectron spectroscopy, Auger electron spectroscopy, and transmission electron microscopy to characterize an electropolished NiTi stent surface coated by laser-generated Au and Ti nanoparticles. The deposition of elemental Au and Ti nanoparticles is observed on the total 3D surface. Ti-coated samples are composed of Ti oxide and Ti carbide because of nanoparticle fabrication and the coating process carried out in 2-propanol. The interface between nanoparticles and the electropolished surface consists of a smooth, monotone elemental depth profile. The interface depth is higher for the Ti nanoparticle coating than for the Au nanoparticle coating. This smooth depth gradient of Ti across the coating-substrate intersection and the thicker interface layer indicate the hard bonding of Ti-based nanoparticles on the surface. Accordingly, electron microscopy reveals nanoparticles adsorbed on the surface without any sorption-blocking intermediate layer. The physicomechanical stability of the bond may benefit from such smooth depth gradients and direct, ligand-free contact. This would potentially increase the coating stability during stent application.
authors: Laser Zentrum Hannover eV, Hannover, Germany.
authors: Anne
authors: A
authors: Neumeister
authors: Daniel
authors: D
authors: Bartke
authors: Niko
authors: N
authors: Bärsch
authors: Tobias
authors: T
authors: Weingärtner
authors: Laure
authors: L
authors: Guetaz
authors: Alexandre
authors: A
authors: Montani
authors: Giuseppe
authors: G
authors: Compagnini
authors: Stephan
authors: S
authors: Barcikowski
mesh_terms: D004586:Electrophoresis; D006046:Gold / Q000737:chemistry; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry*; D015607:Stents; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D006046:Gold; D014025:Titanium