Investigations into the response to implant debris tend to concentrate on how a population of cells proliferate in the presence of implant material, and how the regulation of cytokines change. For the problem of cobalt-chromium (CoCr) implants this has been done for osteoblasts and osteoclasts to understand how bone resorption, leading to aseptic loosening, is occurring. However, investigating the formation of the extracellular-matrix (ECM) may give a better indication of the mechanisms occurring. ECM is excreted from cells and is important for adhesion, structure, signaling and growth. Type I collagen is the most abundant protein in the ECM and is known to direct tissue development and is therefore a key part of understanding the mechanism behind aseptic loosening. 3T3-fibroblasts were seeded in Dulbecco's Modified Eagle Medium (DMEM) and supplemented with 100mM ascorbic acid. Every 48hours cells were fed with DMEM and doped with Co and Cr ions until fixation. Sirius Red dye was used to bind to the type I collagen, then removed using NaOH and analysed using UV absorption to show relative amounts of collagen. Type I collagen gel was formed in the presence of Co and Cr ions with and without DMEM and the fibers were imaged using AFM.Background
Methods
