Liquid crystals help examine mechanical properties of red blood cells

Red blood cells deliver oxygen to all body parts. In order to navigate tight turns in billions of tiny capillaries, they have to be incredibly flexible. Some diseases, like sickle cell anemia and malaria, the flexibility of red blood cells is impaired and that causes a whole lot of problems. Now an international team of scientists took a deeper look into the mechanical properties of red blood cells.

Human red blood cells are very small  (just about 6–8 μm in diameter) and have to be incredibly flexible. Image credit: Naz Amann via Wikimedia (CC BY 4.0)

Red blood cells are very small, which makes them very difficult to research. How do you check something’s flexibility, if you can’t really squeeze and flex it? That is why scientists designed a new method of using synthetic liquid crystals to squeeze red blood cells. For this particular purpose scientists used chromonic phase liquid crystals, formed from aqueous solutions of disodium cromoglycate. This crystal, which was originally developed as a treatment for asthma, is able to  host living mammalian cells without destroying the cell membrane, making it perfect for this purpose.

Although at first scientists saw the red blood cells swell and pop, they managed to adjust the balance of the pressure and the composition of the liquid crystal in a way that allowed red blood cells to survive for longer. When scientists balanced the osmotic pressure, they were able to manipulate the forces exerted on the cells. This is done by increasing the temperature and tuning the concentration. This allowed deforming the red blood cells in several different ways, folding them and stretching them, which allowed assessing their flexibility very accurately. Scientists noticed that cells displayed varying degrees of stiffness – they were highly variable in their mechanical properties.

Nicholas Abbott, lead author of the research, said: “There’s a lot of heterogeneity within the population. If you want to understand the origins of disease, and you want to understand the effects of biological agents on cells, you have to consider that not every cell is the same as the one next to it.” Scientists say that this method allows analyzing thousands of red blood cells at once and helps determine mechanical properties of the entire population. And this is the strength of this method – it is relatively quick and very precise. Scientists say that the same method could be applied to other types of cells and could even differentiate between healthy and diseased cells.

And that’s what this research was all about. Scientists wanted to see the mechanical properties of the red blood cells, but more than anything they wanted to perfect their method, to expand its possibilities and describe the results. Hopefully, this method helps achieve many scientific discoveries in the future.


Source: Cornell University

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