Fibronectin adsorption on gold, Ti-, and Ta-oxide investigated by QCM-D and RSA modelling

The adsorption of fibronectin on gold, Ti-, and Ta-oxide surfaces is investigated by means of the quartz crystal microbalance with dissipation (QCM-D) technique. The surface chemistry (gold, Ti-, and Ta-oxide) is found to influence the frequency shift observed during adsorption of the fibronectin layer with the magnitude being ΔfAu>ΔfTi-oxide∼ΔfTa-oxideΔfAu>ΔfTi-oxide∼ΔfTa-oxide. Corresponding variations in the dissipation change normalised to frequency change (ΔD/ΔfΔD/Δf) for the layer are observed. The QCM-D data are further analyzed by the random sequential adsorption (RSA) model, and adsorption rate parameter kaka and footprint (a) determined, which supported the trend seen in the Δf   and ΔD/ΔfΔD/Δf values. The value of kaka found by the RSA modelling of the QCM-D resonance frequency data is found to match the ratio between the mass measured by QCM-D and the mass reported by optical techniques in literature. We conclude that comparison of the adsorption rate parameter (kaka) obtained by RSA modelling of the QCM-D data with kaka values obtained from RSA modelling of data obtained using optical techniques can be a route to determine the degree of hydration of the adsorbed protein layer.

Adsorption rate vs the surface mass density for fibronectin adsorption on gold. Quartz crystal microbalance with dissipation data and random sequential adsorption (RSA) fitting to the data are shown.Figure optionsDownload as PowerPoint slide