When the supply of donated blood becomes insufficient, platelets become even more scarce. These cell fragments are essential for blood clotting but have a short shelf life. Whole blood can be stored refrigerated for up to a month, but platelets can only be stored for a week at most.
“Even if you have a large endowment, you can’t keep it in the bank for a long time,” said Ashley Brown, an associate professor in the joint biomedical engineering program at North Carolina State University and the University of North Carolina at Chapel Hill.
To address this problem, Brown and her team created an artificial replacement that can be stored for a long time.in recent papers scientific translational medicinethey describe the use of synthetic platelets to stop bleeding and promote healing in rodents and pigs.
Natural platelets circulate in the blood and prevent or stop bleeding by forming blood clots. In some cases, the body may need more of them. People with trauma, cancer, and certain chronic diseases that cause low platelet counts often require blood transfusions. Platelets are usually collected through a process called apheresis. In this process, the donor’s blood is sent through a tube to a machine that separates the platelets. These are poured into a bag and the remaining blood is returned to the donor.
Additionally, because of their limited shelf life, they are often not stored in local hospitals and cannot be easily transported. Brown’s goal is to create an easy-to-store and ship alternative that can be quickly provided to patients, regardless of their blood type, in ambulances or on the battlefield.
To create synthetic platelets, Brown and her team used squishy water-based gels called hydrogels to form nanoparticles that mimic the size, structure, and shape of natural platelets. They then designed an antibody fragment that binds to fibrin, a protein that helps platelets form clots, and decorated the nanoparticle’s surface with this fibrin antibody. When an injury occurs, platelets flood the injury site and form a temporary plug. Fibrin is also activated in this process and accumulates at the wound site, eventually producing a blood clot.
To find the optimal dose of artificial platelets needed to stop bleeding, researchers tested a range of doses in mice. They then injected the artificial versions into mice, rats, and pigs and compared them to animals that received natural platelets and animals that received neither. All animals in the study had severe internal bleeding. They found that synthetic platelets can travel through the bloodstream to the wound site, promote clotting, and promote healing.
Cure rates were similar in animals receiving synthetic platelets and animals receiving natural platelets. Overall, both groups performed better than the untreated group. Interestingly, the researchers only needed to use about one-tenth the amount of artificial particles to achieve the same healing effect as natural platelets. “Our mechanism of action is to bind to fibrin, so it’s possible that our particles are simply more efficient at that binding,” Brown says. There are also variations in the way natural platelets are prepared by laboratories, which may affect quality, which may have accentuated this difference.
