A Modification of Red Blood Cells by Isocyanates

Modified red cells that have a reinforced membrane and hemoglobin which is difficult to denature are prepared by treating red cells with some isocyanates. These modified cells have the same shape as normal red cells, but they are not lysed by osmotic pressure or by the actions of any reagents except for some ionic surface-active agents. No agglutination was observed when they were mixed with the blood of foreign animals or with blood of different blood groups. The hemoglobin within the cell gave a reversible oxygenation curve and had a high oxygen affinity. Toluene-2,4-diisocyanate was found to be the most suitable reagent among the many isocyanates examined. A suspension reaction method which consists of the addition of an isocyanate emulsion to a red-cell suspension at 5°C is developed for the modification process.