Reactive ion etching for fabrication of biofunctional titanium nanostructures

Abstract

One of the major problems with the bone implant surfaces after surgery is the competition of host and bacterial cells to adhere to the implant surfaces. To keep the implants safe against implant-associated infections, the implant surface may be decorated with bactericidal nanostructures. Therefore, fabrication of nanostructures on biomaterials is of growing interest. Here, we systematically studied the effects of different processing parameters of inductively coupled plasma reactive ion etching (ICP RIE) on the Ti nanostructures. The resultant Ti surfaces were characterized by using scanning electron microscopy and contact angle measurements. The specimens etched using different chamber pressures were chosen for measurement of the mechanical properties using nanoindentation. The etched surfaces revealed various morphologies, from flat porous structures to relatively rough surfaces consisting of nanopillars with diameters between 26.4 ± 7.0 nm and 76.0 ± 24.4 nm and lengths between 0.5 ± 0.1 μm and 5.2 ± 0.3 μm. The wettability of the surfaces widely varied in the entire range of hydrophilicity. The structures obtained at higher chamber pressure showed enhanced mechanical properties. The bactericidal behavior of selected surfaces was assessed against Staphylococcus aureus and Escherichia coli bacteria while their cytocompatibility was evaluated with murine preosteoblasts. The findings indicated the potential of such ICP RIE Ti structures to incorporate both bactericidal and osteogenic activity, and pointed out that optimization of the process conditions is essential to maximize these biofunctionalities.

On the Use of Black Ti as a Bone Substituting Biomaterial: Behind the Scenes of Dual‐Functionality

“…[ 51 ] Yet a wider range of surfaces can be produced by taking advantage of other (ICP) RIE processing parameters. [ 44 ] Therefore, the optimum etched surfaces for a certain or multiple bio‐functionality are yet to be established. Moreover, the literature offers limited data over the interactions of bTi surfaces with mammalian cells, especially those involved in the regeneration of bone tissue.…”

“…Among the ICP RIE processing parameters, the temperature and pressure of the chamber are two variables that significantly impact the etching rate and morphology of the resulting structures. [ 44 ] At higher pressures, the energy of ions and radicals decreases as a result of increased number of collisions between them, which eventually decreases the etching rate (i.e., yields shorter pillars for a constant etching time). Increasing the temperature enhances the etching rate of the sidewalls of the initially formed pillars, resulting in further separation and lower compactness of the pillars.…”

“…Nevertheless, the bio‐inertness of titanium is still preserved in form of TiO x as the main component of the etched structures. [ 44 ]…”

“…Among numerous nano‐/microfabrication techniques, reactive ion etching (RIE) is a simple and fast technique for creating an engineered surface topography. [ 44 ] RIE works based on dry chemical etching and physical ion bombardment of the surface. Ivanova et al.…”

Nano-Modified Titanium Implant Materials: A Way Toward Improved Antibacterial Properties

“…There are several methods to fabricate nanopatterns, and the commonly used methods are chemical etching ( Heidarpour et al, 2020 ), reactive ion etching ( Ganjian et al, 2019 ), plasma etching ( He et al, 2013 ), hydrothermal synthesis ( Jaggessar and Yarlagadda, 2020 ; Wategaonkar et al, 2020 ), and anodic oxidation ( Mohan et al, 2020 ). The antibacterial nanopatterns with different antibacterial efficiencies have been prepared by these methods, but the antibacterial effect of these patterns is still not very satisfactory, which may be due to the fact that the production of antibacterial surfaces on titanium and its alloys are more difficult than other materials [silicon, polymethylmethacrylate (PMMA), etc.].…”