Device improves reproducibility of red blood cell deformation measurements

Red blood cells, or RBCs, deliver oxygen throughout the body, reaching tiny capillaries by compressing and deforming as they flow. The deformability of RBCs is a useful diagnostic for diseases that cause stiffening in the cells.

Techniques for testing RBC deformability with single and multiple cells exist, but they suffer from limitations, such as low throughput and the number of variables that can be measured simultaneously. Masnok et al. presented an improved technique allowing for precise, direct observations of RBC deformation using a sinusoidal shear flow generator.

“We wanted to develop a method to evaluate a blood cell’s performance, specifically deformability,” said coauthor Nobuo Watanabe. “We thought to use physiological blood flow, which is a changing shear flow, and adapt it to work as a sinusoidal shear flow in a more precise way than had been achieved previously.”

Sinusoidal shear flow generators are typically unable to create the consistent motion needed for the precision required in clinical settings. By refining a previous design, the authors improved a sinusoidal shear flow generator that creates an oscillatory shear flow in a narrow gap between two parallel glass plates.

The setup was used to study deformation of single RBCs along two axes. The results showed the same time series deformation change under cyclic sinusoidal shear flow along both axes, suggesting the changing shear stress was fully due to that flow and a result of mechanical improvements to the generator.

The researchers hope the device will eventually be useful in clinical settings. They are continuing to work on improvements to the system.

Source: “Direct observation of deformation of individual red blood cells in oscillatory fluid flow produced using a generator of precise sinusoidal shear flow,” by Kriengsak Masnok, Masataka Inoue, and Nobuo Watanabe, AIP Advances (2022). The article can be accessed at https://doi.org/10.1063/5.0113873 .