Red blood cells (RBCs) take up oxygen from the lungs and deliver it to the body's tissues. These disk-shaped cells contain millions of molecules of hemoglobin - an iron containing protein that binds oxygen.
Scientists have tried to create artificial synthetic red blood cells that mimic the properties of natural ones, such as flexibility, oxygen transport and long circulation times. Wei Zhu, C. Jeffrey Brinker and few others from Sandia National Laboratories (SNL) have made synthetic red blood cells that have all of the cells' natural abilities. SNL is managed and operated by the National Technology and Engineering Solutions of Sandia (a wholly owned subsidiary of Honeywell International)
The researchers made the synthetic cells by first coating donated human RBCs with a thin layer of silica. They layered positively and negatively charged polymers over the silica-RBCs, and then etched away the silica, producing flexible replicas. Finally, the team coated the surface of the replicas with natural RBC membranes. The artificial cells were similar in size, shape, charge and surface proteins to natural cells, and they could squeeze through model capillaries without losing their shape. In mice, the synthetic RBCs lasted for more than 48 hours, with no observable toxicity.