Simple and sensitive method for in vitro monitoring of red blood cell viscoelasticity by Quartz Crystal Microbalance with dissipation monitoring (QCM-D)

Viscoelasticity (VE) is the intrinsic mechano-dynamic property enabling red blood cells (RBCs) to undergo prompt and repeated deformations while maintaining structural integrity. Assessing RBC VE and how different stressors can affect it is of great interest. Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) is a technology exploiting high-frequency acoustic waves to probe soft matter rheological properties. In the present study, a QCM-D method is reported for in vitro monitoring of cell VE in viable RBCs. The method is based on casting a sensor-adherent cell monolayer and modeling it as an effective viscoelastic medium, and allows to extrapolate proxy values of both the elastic and the viscous cell shear moduli. Real-time VE changes induced by the known cell VE stressors temperature, medium tonicity, glutaraldehyde, methyl-β-cyclodextrin and cytochalasin D have been reliably identified. The method is relatively simple and inexpensive, non-invasive, and able to seize subtle changes of cell biomechanics. Hence, it could be usefully exploited for in vitro assessment of RBC rheological properties and their alterations induced by external chemico-physical stimuli.