A team of scientists at UCSB, in collaboration with scientists from the University of Michigan, developed a material that can mimic the biological properties of red blood cells.

These synthetic red blood cells, or sRBCs, have the flexibility and oxygen-carrying capacity that make natural red blood cells so vital for life.

Nishit Doshi, a chemical engineering Ph.D. candidate at UCSB and lead author of the paper, which was published in the journal Proceedings of the National Academy of Science, described how the protein hemoglobin allowed the sRBCs to carry oxygen.

“Hemoglobin, a protein innate to natural RBCs, is responsible for the oxygen-carrying capacity,” Doshi said. “[It] was used as one of the proteins for the fabrication of sRBCs, which imparts oxygen-carrying capacity to these sRBCs.”

While the sRBCs developed by Doshi’s research group are not the first synthesized material with the ability to carry oxygen, they have a great advantage over previous materials in that they — like natural red blood cells — are soft and flexible enough to fit into blood vessels smaller in diameter than the cells themselves. According to Doshi, this flexibility is a result of the method by which the sRBCs are synthesized.

“The fabrication process of sRBCs makes them flexible inherently. A polymeric template is coated with proteins and polyelectrolytes, followed by removal of the template core by a solvent which makes them flexible,” Doshi said.

Samir Mitragotri, principal investigator of Doshi’s research group and coauthor of the paper, described how the practical applications of the sRBCs can extend beyond the creation of a blood substitute.

“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,” Mitragotri said 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.”

Doshi said the research team has proven that the sRBCs are capable of carrying drugs, and their ability to move through the patient’s circulatory system provides this method of treatment a significant advantage over other methods for certain diseases.

“As a proof of concept, we have shown that Heparin, a routinely used anticoagulant for the treatment of thrombosis, can be released in a controlled manner from sRBCs,” Doshi said. “Depending on the specific application, Heparin can be replaced by various other drugs.”

In addition to these applications, sRBCs can be made to mimic deformed blood cells, such as those of individuals suffering from sickle-cell anemia, possibly allowing scientists to better understand how the red blood cells are deformed or otherwise affected by the diseases.

“In certain disease conditions, the shape of natural RBCs gets transformed into other shapes such as elliptical or spherical,” Doshi said. “We are able to mimic these shapes using the methods developed in our lab. Such disease cell mimicking particles can serve as synthetic models to help elucidate the effect of transformation in physical properties of RBCs in these disease conditions.”