Temperature-induced shape transformation of carrier erythrocytes

Erythrocytes have been proposed as cellular carriers for enzymes and drugs for protected delivery, slow release, or targeting to specific organs. Several studies have established the heterogeneity of resealed carrier erythrocytes concerning various characteristics, including morphology. Carrier erythrocytes were prepared by hypo-osmotic dialysis and consecutive iso-osmotic resealing at different temperatures, and the morphology of these cells was studied by scanning electron microscopy. Different cell shapes could be prepared by temperature variations during resealing or incubation. All intermediate shapes of echinocytosis were observed at low temperatures or with depleted energy supply but could be reversed to biconcave discocytes. Resealing at 4 degrees C resulted in highest percentage of echinocytes III, spherocytes, and leaky cells. Spontaneous resealing of 20% of the cells was obtained at high lysis temperatures. Combining low temperatures for lysis and high temperatures for resealing and sufficient energy supply are advantageous for highest recovery of biconcave discocytes. Shape of the erythrocyte, is the result of divergent forces, and temperature during resealing was found to be an important factor.