Measuring osmosis and hemolysis of red blood cells

Abstract

Since the discovery of the composition and structure of the mammalian cell membrane, biologists have had a clearer understanding of how substances enter and exit the cell's interior. The selectively permeable nature of the cell membrane allows the movement of some solutes and prevents the movement of others. This has important consequences for cell volume and the integrity of the cell and, as a result, is of utmost clinical importance, for example in the administration of isotonic intravenous infusions. The concepts of osmolarity and tonicity are often confused by students as impermeant isosmotic solutes such as NaCl are also isotonic; however, isosmotic solutes such as urea are actually hypotonic due to the permeant nature of the membrane. By placing red blood cells in solutions of differing osmolarities and tonicities, this experiment demonstrates the effects of osmosis and the resultant changes in cell volume. Using hemoglobin standard solutions, where known concentrations of hemoglobin are produced, the proportion of hemolysis and the effect of this on resultant hematocrit can be estimated. No change in cell volume occurs in isotonic NaCl, and, by placing blood cells in hypotonic NaCl, incomplete hemolysis occurs. By changing the bathing solution to either distilled water or isosmotic urea, complete hemolysis occurs due to their hypotonic effects. With the use of animal blood in this practical, students gain useful experience in handling tissue fluids and calculating dilutions and can appreciate the science behind clinical scenarios.

Aggregation-free and high stability core–shell polymer nanoparticles with high fullerene loading capacity, variable fullerene type, and compatibility towards biological conditions

“…The negative control was PBS buffer, in which the RBCs do not disintegrate owing to the isotonic effect and a net zero movement of molecules across the membrane. 36 The positive control was deionized water, in which RBCs disintegrate fully due to a hypotonic effect and movement of pure water into the cells through osmosis, resulting in bursting of the cell walls. In the case of nanoparticles, however, no hemolysis was observed even at a concentration of 1000 μg mL −1 (ESI Fig.…”

Bioreactivity of Stent Material: <i>In Vitro</i> Impact of New Twinning-Induced Plasticity Steel on Platelet Activation

“…Deionized water was employed as the positive control because its hypotonicity which induces complete hemolysis. Similarly, normal saline was set as the blank control because its isotonicity [9] [32]. The percentage of hemolysis was then calculated as the ratio of OD obtained with the test material with blank subtraction to OD obtained with the positive control with blank subtraction [33], as in Equation (1).…”

The effect of sample hemolysis on blood ethanol analysis using headspace gas chromatography

“…When the blood is mixed with the hypotonic internal standard solution in the headspace vial, the blood cells would hemolyze. A 1:1 dilution of blood with deionized water is expected to cause 100 percent hemolysis of the blood cells [36]. Therefore, all blood samples prepared using a 1:10 dilution with an aqueous internal standard solution would be hemolyzed in the headspace vial prior to incubation.…”