Improving the sensitivity of a quartz crystal microbalance for biosensing by using porous gold

A quartz crystal microbalance can be used as a biosensor if biological rece ptor molecules (ligands) are attached to the crystal. To improve the sensit ivity, the surface area of the gold electrodes on the crystal was increased by rendering the electrodes porous. This increased the response up to a fa ctor of 3. A protein model system with human anti-myoglobin as ligand and s heep skeletal myoglobin at different concentrations as analyte was used. Th e quartz crystal was mounted in a flow-cell, where immobilisation, binding and regeneration of the surface were carried out. The kinetics of the model system was monitored under various experimental conditions.