Hemoglobin-based oxygen carriers camouflaged with membranes extracted from red blood cells: Optimization and assessment of functionality

Despite being an indispensable clinical procedure, the transfusion of donor blood has important limitations including a short shelf-life, limited availability and specific storage requirements. Therefore, a lot of effort has been devoted to developing hemoglobin (Hb)-based oxygen carriers (HBOCs) that are able to replace or complement standard blood transfusions, especially in extreme life-threatening situations. Herein, we employed a Hb-loaded poly(lactide-co-glycolide) core which was subsequently coated with nanozymes to protect the encapsulated Hb from oxidation by reactive oxygen species. To render HBOCs with long circulation in the vasculature, which is a crucial requirement to achieve the high oxygen demands of our organism, the carrier was coated with a red blood cell-derived membrane. Three coating methods were explored and evaluated by their ability to repel the deposition of proteins and minimize their uptake by an endothelial cell line. Preservation of the oxygen carrying capacity of the membrane-coated carrier was demonstrated by an oxygen-binding and releasing assay and, the functionality resulting from the entrapped nanozymes, was shown by means of superoxide radical anion and hydrogen peroxide depletion assays. All in all, we have demonstrated the potential of the membrane-coated nanocarriers as novel oxygen carrying systems with both antioxidant and stealth properties.