Figure 4.

QCM-D measurements for direct adsorption experiments of proteins onto negatively-charged PS hydrophobic surfaces. The curves labeled with the protein names correspond to the changes in resonance frequency $\Delta f_n/n$ of the QCM crystal as a function of time due to the addition of 1 mg/mL protein solution. We also show the energy dissipation $\Delta D_n$ measured during the same experiments (unlabeled curves). Black arrows indicate the time at which the crystal is rinsed with protein-free buffer solution. The overtones from $n=3$ to $n=13$ are represented in different tonalities from dark to pale. The adsorbed mass indicated in the figure is obtained using Equation (6) as explained in the main text.