Differences in the surface composition of seemingly similar F75 cobalt-chromium micron-sized particulates can affect synovial fibroblast viability.

We present data and analyses concerning the cytotoxicity and bioreactivity associated with the surface composition of fine metal particulates that are similar to those commonly released in the body by prostheses used in total joint replacement surgery. Here we study the bulk and surface compositions of three separately procured cobalt-chromium-molybdenum (CoCrMo) micron-sized particulate powders, each identified by their corresponding vendor as being ASTM F75 grade material. We use energy dispersive spectroscopy (EDS) to verify the bulk metallic composition and X-ray photoelectron spectroscopy (XPS) to examine the surface metallic composition of each CoCrMo powder. Cultured synovial fibroblasts were then exposed to the particulate powders to see how the metallic surfaces might affect cellular viability. Results indicate that while the bulk metallic composition of each CoCrMo powder was similar, the surface metallic compositions were found to be dramatically different and yielded equally dramatic differences in terms of cytotoxicity and bioreactivity of synovial fibroblast in culture.

Binary-optic smoothing with isotropic etching.

Binary optics are an important part of modern optics, but they have some inherent problems because of their binary nature. The optics cannot achieve maximum efficiency unless the rms surface error can be reduced. A technique for smoothing jagged surfaces by use of isotropic etching is presented. We show that etching smoothes the binary nature and improves the optical efficiency.