A Monolithic QCM Array Designed for Mounting on a Flow Cell

A monolithic quartz crystal microbalance (QCM) array fabricated with the excitation electrodes located on the airside and the gold conductive layer on the sensing side was evaluated as a biosensor array in a simple flow cell. The electrode configuration of the new QCM is suitable for sensor applications in flow-cell systems compared with standard QCM because the mounting of the QCM on the flow cell and the electric interconnection between the excitation electrode and oscillation circuit does not require considerable skill and effort. Frequency response to the adsorption of human IgG to anti-human IgG antibody at the concentrations of 0.1-100 g/ml was successfully measured, and the results showed that this new sensor can be an alternative to the standard QCM. In addition, the affinity difference between the reference QCM coated with bovine serum albumin for reducing nonspecific binding and the antibody-immobilized QCM to anti-human IgG antibody was simultaneously measured by using the monolithic QCM array within the flow cell. The monolithic QCM array designed for mounting on a flow cell will be expected to use for studying a surface science in a microchannel.