Piezoelectric crystal biosensors.

The recent development of piezoelectric devices as biosensors is reviewed. Biological materials, like enzymes, lipids, antibodies and antigens, have been used as specific coatings and were utilized for the determination of different substrates. Methods of protein coating and several applications are reported including microgravimetric immunoassays, microbial assays, DNA hybridization, enzyme detections and gas phase biosensors. Although the piezoelectric immunochemical sensor is convenient to use and very promising, a thorough understanding of the different phenomena associated with crystals frequency measurement in biological reactions is still lacking and deserves further investigation.