Evaluating the viscoelastic properties and folding dynamics of red blood cells maintained at 4 °C using optical tweezers

This work investigates the viscoelastic properties and folding dynamics of red blood cells (RBCs) at the single-cell level, using optical tweezers. Cell elasticity and membrane viscosity are measured by dragging optically trapped RBCs against the surrounding plasma environment. A custom-developed image processing algorithm is employed for high-throughput processing of single-cell trapping data. The effect of refrigerated plasma storage on the mechanical properties of the cells is investigated by measuring their folding dynamics after one day and seven days of storage for several trapping laser powers and the findings indicate that mechanical stiffening of the cells takes place while they are stored. A novel correlation between RBC area and folding time is established. These results provide new insights into the mechanical behavior of RBCs, which are related to several blood disorders.