Description
QCM-D – Quartz Crystal Microbalance with Dissipation
Label-free technology for the study of molecular interactions and viscoelastic properties of thin and biomolecular films
Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) is a well-established analytical technique for the real-time and label-free monitoring of surface and biomolecular interactions.
The technology enables the quantitative and real-time investigation of processes such as molecular adsorption and desorption, protein–protein and protein–ligand interactions, biomolecular conformational changes, and the formation and reorganization of thin films and biological membranes.
Thanks to its high sensitivity, QCM-D is now considered one of the leading technologies for the characterization of interfaces and biomolecular interactions in biophysics, biochemistry, and materials science.
Principle of QCM-D operation
QCM-D technology exploits the piezoelectric properties of a quartz crystal oscillating at a defined resonance frequency when excited by an alternating electric field.
When molecules or thin films adsorb onto the sensor surface, the resonance frequency changes according to the adsorbed mass, while energy dissipation reflects the viscoelastic properties of the molecular layer. This dual information enables the distinction between simple mass variations and structural modifications occurring within the adsorbed system.
Δf – Frequency variation
The frequency variation (Δf) is directly related to the mass adsorbed onto the sensor surface.
For rigid and thin films, the relationship between frequency shift and adsorbed mass can be described by the Sauerbrey equation. For more complex or viscoelastic systems, the combined analysis of frequency and dissipation provides a more comprehensive characterization of the adsorbed layer.
ΔD – Energy dissipation
Energy dissipation (ΔD) describes the energy lost during crystal oscillation and is influenced by the structural and viscoelastic properties of the system. Parameters such as film elasticity, hydration degree, molecular conformation, and layer rigidity contribute to the dissipative response of the sensor.
Dissipation measurements therefore allow the differentiation between rigid films, soft or highly hydrated layers, and structural reorganization processes occurring within adsorbed biomolecular systems.
Main applications of QCM-D
Protein–protein and protein–ligand interactions
QCM-D enables the real-time study of biomolecular interactions on functionalized surfaces, allowing the analysis of association and dissociation kinetics as well as the characterization of molecular binding processes.
Biological membranes and lipid systems
The technology is widely used for the study of supported lipid bilayers, liposomes, and vesicles, enabling the monitoring of adsorption, fusion, and reorganization processes in biological membranes.
Biomaterials and thin films
QCM-D is employed for the characterization of biomaterials, functional coatings, polymers, and thin films, providing quantitative information on adsorbed mass, viscoelasticity, and surface structural properties.
Biosensors and biopharmaceutical applications
The technique is widely used in the development of label-free biosensors and for the study of high-sensitivity antibody–antigen and drug–target interactions.
Advanced acoustic wave technologies by AWSensors
AWSensors platforms integrate different acoustic wave sensor technologies for advanced biosensing and surface characterization applications.
Available configurations include:
- conventional QCM sensors (5–10 MHz)
- high-frequency HFF-QCM sensors (50–150 MHz)
- LOVE-SAW (Surface Acoustic Wave) sensors
The modular architecture of these systems enables adaptation to different experimental requirements and the combination of multiple operational modes.
The combination of QCM-D, HFF-QCM, and LOVE-SAW technologies enables the advanced characterization of molecular interactions, biomaterials, and functionalized surfaces with high sensitivity and resolution.
Thanks to their label-free and real-time analytical capabilities, these technologies represent essential tools for the study of biomolecular interactions, the development of advanced biosensors, and the characterization of complex materials.
