Nanotubular surface modification of metallic implants via electrochemical anodization technique

Abstract

Due to increased awareness and interest in the biomedical implant field as a result of an aging population, research in the field of implantable devices has grown rapidly in the last few decades. Among the biomedical implants, metallic implant materials have been widely used to replace disordered bony tissues in orthopedic and orthodontic surgeries. The clinical success of implants is closely related to their early osseointegration (ie, the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant), which relies heavily on the surface condition of the implant. Electrochemical techniques for modifying biomedical implants are relatively simple, cost-effective, and appropriate for implants with complex shapes. Recently, metal oxide nanotubular arrays via electrochemical anodization have become an attractive technique to build up on metallic implants to enhance the biocompatibility and bioactivity. This article will thoroughly review the relevance of electrochemical anodization techniques for the modification of metallic implant surfaces in nanoscale, and cover the electrochemical anodization techniques used in the development of the types of nanotubular/nanoporous modification achievable via electrochemical approaches, which hold tremendous potential for bio-implant applications. In vitro and in vivo studies using metallic oxide nanotubes are also presented, revealing the potential of nanotubes in biomedical applications. Finally, an outlook of future growth of research in metallic oxide nanotubular arrays is provided. This article will therefore provide researchers with an in-depth understanding of electrochemical anodization modification and provide guidance regarding the design and tuning of new materials to achieve a desired performance and reliable biocompatibility.

Characterisation of the nanotubular oxide layer formed on the ultrafine-grained titanium

“…This nanostructured surface modification method allows the formation of an oxide layer much thicker than the natural oxide layer formed on the titanium surface [10]. In the electrochemical anodization process, electrolyte with fluoride ions leads to the formation of nanotubular oxide layers [11], while compact oxide layers can be formed in most electrolytes, as presented in Fig. 2.…”

“…For instance, nanotubular oxide layer formed on the Ti-Al alloy is composed of TiO2 and Al2O3. The amounts of these oxides in the nanotubular oxide layer are proportional to the amounts of Ti and Al elements in base alloys [16]. Nanotubular oxide layer formed on the cpTi is composed of a combination of Ti oxides, mainly of TiO 2 and Ti 2 O 3 oxides.…”

TiO₂ nanotube platforms for smart drug delivery: a review

“…30,31 Some researchers have explored the optimization in anodization parameters to achieve a high degree of self-ordering in the grown TNTs. [32][33][34][35][36][37][38][39][40][41] TNT arrays with controllable nanotube diameters and hexagonal arrangement fabricated by electrochemical anodization based on Ti surface with highly ordered nanotube structures are schematically shown in Figure 1. 34,42,43 TNT fabrication is a unique electrochemical process termed self-assembling anodization, 44 which is based on inexpensive materials and equipment.…”

Fabrication and cellular interactions of nanoporous tantalum oxide

“…Via the application of a potential difference between the electrodes, oxygen ions generated at the electrolyte/anode interface move under the action of the electrical field, migrate within the metal attached to the anode and form an oxide surface layer (Momeni, Mirhosseini, Chavoshi, & Hakimizade, 2016). The control of electrochemical parameters, that is, anodization duration, potential, electrolyte concentration, temperature, pH, and so forth, alter oxide layer properties and allow the fabrication of nanofeatured surface morphologies (i.e., nanotubes and nanodimples) (Wang et al, 2014). In literature, there are several studies focusing on the anodization of tantalum.…”