Artificial platelets that help with clot formation have been created in the past, but they’ve been limited in their ability to gather around the site where the coagulation cascade is taking place. Instead they tend to begin promoting the clotting process randomly, potentially creating dangerous blood clots. Moreover, these artificial platelets don’t contract the clot like naturally occurring ones do, probably because of their rigid nature. Now researchers at Georgia Tech and Chapman University in California have developed platelet-like particles (PLPs) that seem to overcome previous limitations, being able to move toward sites where clotting is occurring and contracting the clots much like natural platelets do.
The PLPs are made out of a gel coated with bits of antibodies, particles that have been discovered to grab onto fibrin that is produced around clots, but not fibrinogen, its precursor. Because these platelet-like particles only gather where clotting is already in progress, the researchers hope that PLPs could one day be injected into soldiers about to go into battle, helping to treat wounds as soon as they happen. In addition to gathering and promoting clotting, the PLPs are also soft enough to mimic clot contractions that naturally occur in healthy subjects.
The researchers tested the new particles within a microfluidic device that simulates intravascular environments, as well as on laboratory animals with traumatic injury.
From the National Institute of Biomedical Imaging and Bioengineering, a sponsor of the research:
In the microfluidic chamber, PLPs that were added to platelet-deficient plasma successfully restored clotting function. In addition, PLPs restored diminished clotting function in platelet-deficient plasma samples taken from newborns who had recently undergone bypass to fix heart abnormalities.
Upon examination of PLP-induced clots, it was noted that PLPs spread significantly within the fibrin clot matrix to levels seen with natural platelets. Additional experiments also demonstrated that PLPs induce clot collapse within 24-48 hours. While the overall degree of this collapse was similar to that found with platelet-rich plasma, it occurred at a slower rate. Finally, the researchers injected rats with PLPs five minutes prior to injury of a large blood vessel in the leg. The bleeding times of rats who had received the PLPs were significantly reduced, and this reduction was more significant than in rats who had received a 100-fold platelet infusion.