Optimum control of oxygen affinity of hemoglobin as an oxygen carrier solution for an artificial gill

An artificial gill was developed using a concentrated hemoglobin solution as an oxygen carrier solution, with the oxygen affinity controlled by temperature. Oxygen affinity of the concentrated hemoglobin solution was optimized for the artificial gill by adding inositol hexaphosphate as an allosteric effector and varying the pH and temperature. The oxyhemoglobin dissociation curve shifted to the right with increased ratios of inositol hexaphosphate to hemoglobin, decreased pH values, and higher temperatures. The optimum ratio of inositol hexaphosphate to hemoglobin was 5:1. Because lower pH promotes proton oxidation of hemoglobin, the optimum pH was 6.9. The oxyhemoglobin dissociation curve shifted to the right with higher temperatures. The amount of the shift in relation to temperature change was higher at higher temperatures. The oxygen transfer rate was markedly increased by changing the temperature of the oxygen carrier solution. The overall mass transfer coefficient decreased at higher oxygen partial pressures due to the gentle oxyhemoglobin dissociation curve. The flow rate of the oxygen carrier solution and heat transfer rate for heating of the oxygen carrier solution were markedly decreased by setting the range of temperature changes from 293K to 310K. The flow rate of the oxygen carrier solution required to supply 300 ml (STP)/min of oxygen was 21.71/min, and the heat transfer rate was 1165 kJ/min.