| AVS 58th Annual International Symposium and Exhibition | |
| Biomaterial Interfaces Division | Thursday Sessions |
| Session BI-ThM |
| Session: | Biomedical Materials |
| Presenter: | Lawrence Salvati, DePuy Orthopaedics |
| Authors: | L. Salvati, DePuy Orthopaedics S. Vass, DePuy Orthopaedics |
| Correspondent: | Click to Email |
A biomaterial is defined as “any synthetic material or device–e.g. implant or prosthesis-intended to treat, enhance or replace an aging or malfunctioning native tissue, organ or function in the body” David Williams, states that “Biocompatibility is largely about the chemical interactions that take place between the materials and the body fluids, and the physiological responses to these reactions.” These reactions are dominated by the initial events at the molecular level, the interface, thus it is not hard to see the relationship between the implant surface properties and it's in vivo. It is clear that the performance of a biomaterial is directly linked to the surface chemistry, composition and topography of the device. However, despite the preponderance of evidence, biomedical device companies as a whole do not utilize surafce analytical methods nearly enough. Why is that?
In orthopaedics, most of the implants are fabricated from metals which directly contact biological fluids that are typically complex aqueous mixtures. Consequently corrosion and/or corrosion prevention are important considerations in device manufacturing. For the most part, orthopaedics manufacturers utilize the same passivation methodologies used to impart corrosion resistance to stainless materials. Numerous researchers have characterized the impact of acid passivation on stainless materials, but little has been done to study the effect of these treatments on the CoCr alloys. One of the topics in this presentation deals with the effects of passivation on CoCr alloys. Specifically, the presentation will correlate specific surface treatments with surface chemistry and ultimately to metal ion release. The study will also address questions relating to the use of Citric acid as a green replacement for nitric acid passivation. There is no argument that the process is much greener, but there are plenty of questions as to its effectiveness. Considering that the “changes” imparted by the passivation solutions effect the outer most 10-100A, the only means to characterize the affects of passivation requires surface analysis methodologies. The importance of surface analysis methods, especially XPS, will be highlighted by this example.
In addition to the discussion of metal alloy passivation, this presentation will also deal with other surface related issues that could impact the biocompatibility of biomaterials. The talk will show the potential impact of packaging materials and cleaning processes on the surface chemistry and composition of biomaterials.