Passive films on metallic biomaterials under simulated physiological conditions

Abstract

The metallic materials used for implantable medical devices are predominantly stainless steels, Ti and its alloys, and Co-Cr alloys. The corrosion resistance of each of these materials is associated with a passive oxide film on its surface. Since corrosion resistance is crucial to implant performance, considerable effort has been focused on understanding the nature of the passive film present under physiological conditions. Surface analytical techniques and electrochemical impedance spectroscopy have been used in a number of studies to investigate the passive film formed on metallic biomaterials in simulated physiological solutions. This review focuses on the surface characteristics of these materials with regard to composition, thickness, and impedance of the passive films. Of particular interest are changes in the films with surface treatment and the nature of the films developed over time in the simulated solutions.

Cathodic voltage-controlled electrical stimulation of titanium implants as treatment for methicillin-resistant Staphylococcus aureus periprosthetic infections

“…are passivated with surface oxide films that have voltage-dependent electrochemical properties [23]. In addition to total joint prostheses, these metals are widely utilized for implantable plates, rods, and screws used for fracture fixation and spine surgery.…”

Cathodic Electrical Stimulation Combined With Vancomycin Enhances Treatment of Methicillin-resistant Staphylococcus aureus Implant-associated Infections

“…It is also important to point out that although the present study was conducted with Ti, most of the metals used for orthopaedic implants are also passivated with surface oxide films that have voltage-dependent electrochemical properties [24]. Therefore, the application of cathodic voltagecontrolled electrical stimulation to metallic orthopaedic devices may represent a new and widely applicable treatment modality.…”

Cathodic Voltage-controlled Electrical Stimulation Plus Prolonged Vancomycin Reduce Bacterial Burden of a Titanium Implant-associated Infection in a Rodent Model

“…However, the passive surface film on both of these materials is largely dictated by titanium-oxide and previous studies have shown these metals have very similar surface oxide behavior and voltage-dependent electrochemical properties [2]. It is also important to emphasize that most other metals used for orthopaedic implants such as stainless steel and cobalt-chromium-molybdenum are passivated with surface oxide films that also display voltage-dependent electrochemical properties [12,14,20]. Therefore, although the results presented here are for commercially pure Ti, the antimicrobial strategy of using CVCES to control the voltage-dependent interfacial electrochemical properties of other metal orthopaedic implants may be broadly applicable and should be evaluated in future studies.…”