While the industrial community already employs multiple surface analytical techniques to study compositional wearing of various metallic and nonmetallic materials, as yet, these methods have not been widely introduced into the biological community. We report on a novel approach, using the industrial spectroscopic techniques of X-ray photoelectron spectroscopy, micro-Raman spectroscopy, and scanning electron microscopy equipped with energy dispersive spectroscopy, to identify the fine wear particulates and other impurities deposited within the knee-joint following total knee arthroplasty. In this study, synovial fluid was extracted from knee-joints scheduled for revision of total knee arthroplasty. The small debris flake formed by centrifugation of the fluid was analyzed using the spectroscopic techniques mentioned above. These nondestructive techniques were successful in identifying numerous micron and submicron sized metallic particulates that appear to emanate from both the prosthetic bearing (articulating) surfaces and from backside (nonarticulating) surfaces, even when gross wearing of the prosthetic device was not detectable by direct visual inspection intraoperatively. Most interesting is that the ratio of the in vivo metallic debris is approximately the same ratio as that of the manufactured alloy, indicating prosthetic wearing as opposed to chemical dissolution. More importantly, using these spectroscopic techniques to probe both the surface and below the surface of the synovial deposits, we identify an inhomogeneous distribution of the wear debris. This indicates the need to use multiple techniques in order to adequately identify the elemental composition of the prosthetic wear material.

We present data and analyses concerning the adhesion of clinically relevant Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa (bacteria) and Candida albicans (yeast) to Zircaloy-2 (Zry-2) and Zircadyne-705 (Zr705) surfaces. These zirconium-based materials are similar to those now being used in total hip and knee replacements. Here we study clinical strains of microbes under shaken and stationary exposure conditions, and their ability to adhere to Zr surfaces having different oxide thicknesses. We use X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), viable counts, endotoxin assays, and statistical analysis methods, and demonstrate a predictive model for microbial adhesion based on XPS data.

We report on the use of X-ray photoelectron spectroscopy and scanning electron microscopy equipped with energy dispersive spectroscopy to investigate the metallic content of wear debris from prosthetic knees. Synovial fluid aspirated from patients with prosthetic knees was centrifuged, rinsed and dried, resulting in small deposits of wear debris. We identify the presence and composition of metal wear debris from the femoral, tibial, and in some cases the patellar prosthetic components. We also demonstrate the inhomogeneous size, shape, and distribution of the wear particles, and both lateral and vertical elemental inhomogeneity. This points to the necessity of using a combination of techniques for studying such wear debris. The ability to detect the presence of certain metals within the synovial fluid of patients, even when surgical inspection did not identify wear of specific components, may have far reaching implications in the biomedical and prosthetics communities.

We report large area patterning of sputter-deposited FeN thin films by a high-voltage parallel writing technique that was recently developed to modify ZrN surfaces. Systematically patterned 15–100-nm-thick FeN films consisting of features with well-defined sizes and shapes are obtained by applying high dc voltages between a stamp and the samples. During the process the oxide dissolves, exposing the substrate beneath. This controlled breakdown eliminates the need for any postexposure etching. The single-step imprinting method presented here provides an emerging route to fabricate isolated FeN geometrical structures on silicon substrates for magnetic applications.

We investigate the interaction of sulfur dioxide (SO2) with Zircaloy-4 (Zry-4) surfaces after adsorption at 300K. A shift in the Zr(MNN) feature toward lower energies of about 3eV is observed following saturation exposures, indicating oxidation of Zr by dissociated oxygen. Temperature programed desorption experiments indicate irreversible adsorption. Relatively short Ar-ion sputtering removes sulfur from the near-surface region without significantly affecting the oxygen Auger signal. Annealing of the SO2∕Zry-4 system results in dissolution of oxygen into the bulk, leaving sulfur in the near-surface region.