Reusable chromium-coated quartz crystal microbalance for immunosensing.

The application of oxidized chromium as a reusable platform for the development of immunosensors is presented. Chromium films were deposited on quartz crystal microbalances to study the affinity interaction between rabbit immunoglobulin G (IgG) and goat anti-rabbit IgG. A covalent approach, based on the silane chemistry, was followed for the grafting of either the rabbit IgG or the anti-rabbit IgG on the silane-modified chromium surface. Next the differences between the deposition of rabbit IgG on immobilized anti-rabbit IgG and the deposition of anti-rabbit IgG on immobilized rabbit IgG were investigated. The chromium layer could be reused between experiments, after the proper removal of the organic layers with piranha etch, obtaining a high repeatability in the steps of the functionalization protocol.