Wettability and osteoblastic cell adhesion on ultrapolished commercially pure titanium surfaces: the role of the oxidation and pollution states

Abstract

The oxidation state of the surfaces of titanium-based biomaterials strongly depends on their previous history. This factor affects the titanium wettability and it probably conditions the success of the implanted biomaterials. However, the separate role of the pollution and oxidation states of metallic titanium surfaces remains still controversial. To elucidate this, it is required to standardize the initial surface state of titanium in terms of roughness and surface chemistry, and then, to monitor its wettability after the corresponding treatment. In this work, we studied finely polished surfaces of commercially pure titanium (cpTi) which were subjected to cleaning surface treatments. X-Photoelectron spectroscopy was used to characterize the surface chemistry and the oxide film thickness. The contact angle hysteresis in underwater conditions was measured with the growing/shrinking captive bubble method, which allowed for mimicking the real conditions of implantable devices. The water wettability of smooth cpTi surfaces was stabilized with weak thermal oxidation (230 °C, 30 min). The osteoblastic cell response of the stabilized and non-stabilized cpTi surfaces was analyzed. Although the oxidation and pollution states were also stabilized and normalized, no correlation was observed between the stable response in wettability of titanium and its cell adhesion.

Keywords:

• titanium
• oxidation
• wettability
• captive bubble
• cell adhesion

Acknowledgments

Authors thank to Dr C Rodriguez–Navarro for the XRD measurements, Dr JA Holgado-Terriza for the software Contacto© used for contact angle measurements, JA Martin-Perez, who masterly polished the titanium samples, and CL Moraila-Martinez and Dr FJ Montes Ruiz-Cabello, who kindly helped with the experimental work.

Funding

This study was supported by the ‘Ministry of Science and Innovation’ (project MAT2011-23339) and by the ‘Junta de Andalucia’ (projects P09-FQM-4698 and P10-FQM-5977).