Quartz Crystal Microbalance: Basics and Applications in Biology

The quartz crystal microbalance (QCM) technique refers to a bioanalytical approach capable of monitoring adsorption reactions at the solid liquid interface with the help of thumbnail‐sized piezoelectric quartz crystals that perform resonant shear oscillations of nanometre amplitude. Shifts of its resonance frequency report on mass deposition on the crystal surface with sub‐microgram sensitivity. The device is typically used to study and quantify non‐covalent biomolecular interactions of the ligand receptor type. When the crystal surface is, for instance, functionalised with antibodies, the resulting biosensor captures target molecules or microorganisms from solution and indicates the associated mass change. Growing adherent animal cells on the crystal surface provides a convenient, non‐invasive and label‐free approach to follow changes in cellular micromechanics and adhesion state under physiological conditions. This article provides a brief introduction into the physical basics of the technology and highlights its major applications as well as limitations.