Titanium–Tissue Interface Reaction and Its Control With Surface Treatment

The current development of nanobiotechnologies requires a better understanding of cell-surface interactions on the nanometre scale. Recently, advances in nanoscale patterning and detection have allowed the fabrication of appropriate substrates and the study of cell-substrate interactions. In this review we discuss the methods currently available for nanoscale patterning and their merits, as well as techniques for controlling the surface chemistry of materials at the nanoscale without changing the nanotopography and the possibility of truly characterizing the surface chemistry at the nanoscale. We then discuss the current knowledge of how a cell can interact with a substrate at the nanoscale and the effect of size, morphology, organization and separation of nanofeatures on cell response. Moreover, cell-substrate interactions are mediated by the presence of proteins adsorbed from biological fluids on the substrate. Many questions remain on the effect of nanotopography on protein adsorption. We review papers related to this point. As all these parameters have an influence on cell response, it is important to develop specific studies to point out their relative influence, as well as the biological mechanisms underlying cell responses to nanotopography. This will be the basis for future research in this field. An important topic in tissue engineering is the effect of nanoscale topography on bacteria, since cells have to compete with bacteria in many environments. The limited current knowledge of this topic is also discussed in the light of using topography to encourage cell adhesion while limiting bacterial adhesion. We also discuss current and prospective applications of cell-surface interactions on the nanoscale. Finally, based on questions raised previously that remain to be solved in the field, we propose future directions of research in materials science to help elucidate the relative influence of the physical and chemical aspects of nanotopography on bacteria and cell response with the aim of contributing to the development of nanobiotechnologies. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Dental and orthopedic implants have been under continuous advancement to improve their interactions with bone and ensure a successful outcome for patients. Surface characteristics such as surface topography and surface chemistry can serve as design tools to enhance the biological response around the implant, with in vitro, in vivo and clinical studies confirming their effects. However, the comprehensive design of implants to promote early and long-term osseointegration requires a better understanding of the role of surface wettability and the mechanisms by which it affects the surrounding biological environment. This review provides a general overview of the available information about the contact angle values of experimental and of marketed implant surfaces, some of the techniques used to modify surface wettability of implants, and results from in vitro and clinical studies. We aim to expand the current understanding on the role of wettability of metallic implants at their interface with blood and the biological milieu, as well as with bacteria, and hard and soft tissues. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Metallic biomaterials are used in medical devices in humans more than any other family of materials. The corrosion resistance of an implant material affects its functionality and durability and is a prime factor governing biocompatibility. The fundamental paradigm of metallic biomaterials, except biodegradable metals, has been “the more corrosion resistant, the more biocompatible.” The body environment is harsh and raises several challenges with respect to corrosion control. In this invited review paper, the body environment is analysed in detail and the possible effects of the corrosion of different biomaterials on biocompatibility are discussed. Then, the kinetics of corrosion, passivity, its breakdown and regeneration in vivo are conferred. Next, the mostly used metallic biomaterials and their corrosion performance are reviewed. These biomaterials include stainless steels, cobalt-chromium alloys, titanium and its alloys, Nitinol shape memory alloy, dental amalgams, gold, metallic glasses and biodegradable metals. Then, the principles of implant failure, retrieval and failure analysis are highlighted, followed by description of the most common corrosion processes in vivo. Finally, approaches to control the corrosion of metallic biomaterials are highlighted.