microbilancia

Microbilancia, the Italian term for microbalance, refers to miniature weighing devices designed to measure extremely small masses with high sensitivity. These instruments typically operate in the microgram to nanogram range and are used to monitor mass changes in real time. They are common in chemistry, biology, materials science, and surface science where small sample volumes and rapid measurements are important.

The core principle of most microbalances is that a mass change causes a measurable change in an electrical signal, usually a shift in resonance frequency or cantilever deflection. The quartz crystal microbalance (QCM) is a well-known example: a piezoelectric crystal resonates at a specific frequency, and the adsorption of material onto the surface lowers this frequency. For thin, rigid films, the Sauerbrey equation links the frequency change to added mass. Microcantilever and other MEMS-based microbalances translate mass changes into frequency shifts or deflection, enabling highly integrated, on-chip sensing. Some optical microbalances use interferometric or ring-down techniques to infer mass via changes in optical signals.

Form factors and technologies vary, including QCM sensors with coating layers for surface studies, MEMS cantilevers for on-chip sensing, and other resonant or optical configurations. Applications span real-time monitoring of adsorption processes, thin-film growth, catalysis, and gas sensing, as well as biosensing tasks such as detecting protein–ligand interactions or DNA binding. Microbalances are valued for small sample requirements and rapid, label-free measurements, though they can be sensitive to environmental conditions such as temperature and humidity and may require careful calibration and surface preparation.

Historically, the concept evolved with the development of QCM in the mid-20th century, and advances in MEMS have driven further miniaturization and integration of microbalance sensors.