ACS: Blood transfusions can save the lives of patients who have suffered major blood loss, but hospitals don’t always have enough or the right type on hand. In search of a solution, researchers have developed a promising substitute using blood’s oxygen-carrying component, hemoglobin. The in vitro study, reported in ACS’ journal Biomacromolecules, found that the modified hemoglobin was an effective oxygen carrier and also scavenged for potentially damaging free radicals.
Red blood cells are the most commonly transfused component of blood,
according to the U.S. National Heart, Lung, and Blood Institute. These
cells carry the protein hemoglobin, which performs the essential
function of delivering oxygen to the body’s tissues. Scientists have
tried developing chemically modified hemoglobin — which by itself is
toxic — as a blood substitute but have found that it forms
methemoglobin. This form of the protein doesn’t bind oxygen and thus
decreases the amount of oxygen that blood delivers in the body. In
addition, the generation of methemoglobin produces hydrogen peroxide,
which leads to cell damage. Hong Zhou, Lian Zhao, Yan Wu and colleagues
wanted to see if packaging hemoglobin in a benign envelope could get
around these problems.
The researchers developed a one-step method for wrapping hemoglobin
in polydopamine, or PDA, which has been widely studied for biomedical
applications. A battery of lab tests showed that the PDA-coated
hemoglobin effectively carried oxygen, while preventing the formation of
methemoglobin and hydrogen peroxide. In addition, it caused minimal
cell damage, and acted as an effective antioxidant, scavenging for
potentially damaging free radicals and reactive oxygen species.
The authors acknowledge funding from the National Natural Science Foundation of China and the Beijing Natural Science Foundation.