Electrochemical Behavior of Biomedical Alloys Exposed to Human Synovial Fluid

Most widely used biomedical materials are polymeric, ceramics and metals. Among these materials, metals exhibit a unique combination of mechanical strength, toughness, wear resistance and forming easiness. Metals are chemically reactive when in contact with body fluids. While some of the reactions are welcome, such as the surface oxidation providing corrosion protection, other reactions may adverse the biocompatibility character of the material.The understanding of these reactions is the object of several studies. Corrosion scientists try to characterise the corrosion response of metals when in contact with simulated body fluids in order to verify the occurrence of hypothetical mechanisms. Biologists look at specific reaction products expected to be released by cells when set in contact with structured or functionalized surfaces. These approaches are necessary but also time consuming due to the complexity of possible reaction mechanisms. As complement to these deductive approaches we propose here an inductive one based on direct measurement through electrochemical, gravimetric, spectrophotometric and surface analysis of reaction occurring at the interface between functionalized metal samples and body fluids (synovia) directly extracted from patients.

The general aim of this project is to contribute to develop a comprehensive vision of interfacial reactions occurring on biomedical alloy surfaces exposed to human synovial fluid and to link them to clinical data. This will be achieved through a collaboration between surgeons and corrosion scientists. The synovial fluid will be extracted form patients using an established procedure and transferred to a portable sterile corrosion laboratory located close to the surgery room. There, surface reaction will be characterized using electrochemical methods already successfully applied in recent studies carried out by the same team. We will be integrating in-situ quartz crystal microgravimetry and in-situ Raman spectroscopy as well as ex-situ methods. Further, metal surfaces will be chemically functionalized (wettability, oxidation, surface charge) in order to selectively influence specific reactions of body fluid components (i.e. adsorption depends on surface energy and wettability while Redox reactions are influenced by the oxidation state of the surface. The acquired information will be compared to the clinical state of the patient in order to establish possible correlations between interface reactivity and patient state.

Inclusion criteria

• indication to knee joint puncture
• Written consent

Exclusion criteria

• refusing to sign written consent
• patient unabled to have a follow-up by their own surgeon/doctor