Functional Nanoarchitectures For Enhanced Drug Eluting Stents

© The Author(s) 2017. Different strategies have been investigated to allow for optimum duration and conditions for endothelium healing through the enhancement of coronary stents. In this study, a nanoarchitectured system is proposed as a surface modification for drug eluting stents. Highly oriented nanotubes were vertically grown on the surface of a new Ni-free biocompatible Ti-based alloy, as a potential material for self-expandable stents. The fabricated nanotubes were self-grown from the potential stent substrate, which are also proposed to enhance endothelial proliferation while acting as drug reservoir to hinder Vascular Smooth Muscle Cells (VSMC) proliferation. Two morphologies were synthesized to investigate the effect of structure homogeneity on the intended application. The material was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Nanoindentation technique was used to study the mechanical properties of the fabricated material. Cytotoxicity and proliferation studies were performed and compared for the two fabricated nanoarchitectures, versus smooth untextured samples, using in-vitro cultured endothelial cells. Finally, the drug loading capacity was experimentally studied and further supported by computational modeling of the release profile

Ternary Ti-Mo-Fe Nanotubes as Efficient Photoanodes for Solar-Assisted Water Splitting

Designing efficient and stable water splitting photocatalysts is an intriguing challenge for energy conversion systems. We report on the optimal fabrication of perfectly aligned nanotubes on trimetallic Ti-Mo-Fe alloy with different compositions prepared via the combination of metallurgical control and facile electrochemical anodization in organic media. The X-ray diffraction (XRD) patterns revealed the presence of composite oxides of anatase TiO2and magnetite Fe3O4with better stability and crystallinity. With the optimal alloy composition Ti-(5.0 atom %) Mo-(5.0 atom %) Fe anodized for 16 h, enhanced conductivity, improved photocatalytic performance, and remarkable stability were achieved in comparison with Ti-(3.0 atom %) Mo-(1.0 atom %) Fe samples. Such optimized nanotube films attained an enhanced photocatalytic activity of ∼0.272 mA/cm2at 0.9 VSCE, which is approximately 4 times compared to the bare TiO2nanotubes fabricated under the same conditions (∼0.041 mA/cm2at 0.9 VSCE). That was mainly correlated with the emergence of Mo and Fe impurities within the lattice, providing excess charge carriers. Meanwhile, the nanotubes showed outstanding stability with a longer electron lifetime. Moreover, carrier density variations, lower charge transfer resistance, and charge carriers dynamics features were demonstrated via the Mott-Schottky and electrochemical impedance analyses

Study on hot deformation behavior of beta Ti-17Mo alloy for biomedical applications

Abstract A novel biomaterial Ti-17Mo (mass%) was designed for orthopedic implant applications. Hot working behavior and deformation characteristics were studied in the β-single structure by hot compression tests in the strain rate range 0.01–10 s−1 and temperature range 1123–1273 K using a Thermec Master-Z simulator. The microstructural evolutions of the deformed alloy were studied by a scanning electron microscope equipped with an electron backscattered diffraction detector. The microstructures of the hot deformed alloy showed that dynamic recovery was more active than dynamic recrystallization (DRX). However, partial discontinuous DRX by grain boundary bulging is activated at high temperatures and low strain rates, e.g., 1273 K and 0.01 s−1. Due to the high stacking fault energy of the β phase with a bcc structure, the Ti-17Mo alloy possessed comparatively low activation energy of hot deformation (283 kJ/mol) compared with the conventional Ti alloys bearing multiple alloying elements