Design and application of piezoelectric quartz crystal-based immunoassay

This paper describes some basic test schemes of piezoelectric quartz crystal microbalance (QCM)-based immunoassay. These include one-step direct assay, one-step indirect assay, two-step sandwiched assay, displacement assay, and mass-amplified assay. Applications of these designs in the fields of clinic diagnosis, food analysis, environmental analysis, and veterinary diagnosis are reviewed. In addition, some critical issues of QCM immunoassay are also dealt with, including the evaluation of liquid phase and gas phase detection, and the biomolecules' coating techniques, non-specific adsorption, and regeneration of used crystals.