Detection of gold colloid adsorption at a solid/liquid interface using micromachined piezoelectric resonators

Microfabricated piezoelectric resonators have been used in a liquid environment for real time detection of gold colloid adsorption at a solid/liquid interface. Negatively charged gold colloids in suspension in a buffer solution adsorb on the surface of the piezoelectric microresonator passivated with a silicon dioxide layer that has been functionalized with an amino-silane self-assembled monolayer. The mass loading induced by adsorption on the surface of the piezoelectric resonator leads to a change in resonant frequency. Measured frequency shift as a function of time incubation in a colloidal suspension was observed and correlated with the mass of adsorbed gold colloids.