Synthetic Blood Cells Could Deliver Drugs

Scientists from the University of California, Santa Barbara (UCSB) and the University of Michigan jointly developed synthetic particles that exhibit the characteristics and perform the functions of red blood cells. The researchers published their findings on the website of the Proceedings of the National Academy of Sciences last week, and the article will appear in the print version of the journal soon.

The synthetic red blood cells (sRBCs) carry oxygen as natural red blood cells do; about 90% of sRBCs’ oxygen-binding capacity is intact after a week. In their article, the scientists said that the sRBCs also can be used for the controlled release of drugs and to carry contrast agents to improve the resolution of diagnostic imaging.“This ability to create flexible biomimetic carriers for therapeutic and diagnostic agents really opens up a whole new realm of possibilities in drug delivery and similar applications,” said Samir Mitragotri, chemical-engineering professor at UCSB, in a press release. “We know that we can further engineer sRBCs to carry additional therapeutic agents, both encapsulated in the sRBC and on its surface.”

To create the sRBCs, the research group created a polymer-based template shaped like a doughnut. Next, they coated the template with several layers of hemoglobin and other proteins and removed the core template. The result was a carrier about the size of natural red blood cells (approximately 5 µm in diameter) that can carry as much oxygen as natural red blood cells. Unlike traditional polymer-based biomaterials developed as drug-delivery mechanisms, the sRBCs are flexible enough to flow through channels narrower than their own diameter.

Like natural red blood cells, the sRBCs stretch in response to flow and regain their original shape when they exit the channel. The scientists said that their technique can also be used to develop particles that simulate the shape and properties of diseased cells such as those found in sickle-cell anemia and hereditary eliptocytosis. Synthetic diseased cells could help researchers learn how diseases affect natural red blood cells.

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