Pseudo-platelet Drug Delivery System Targets Cancer Researchers are using patients own platelet membranes to coat drugs and use as nanovehicles for anticancer treatments.

A paper published online Sept. 29 in Advanced Materials outlines the work successfully done in animal models.

Corresponding author Zhen Gu, an assistant professor in the joint biomedical engineering program at North Carolina State University and the University of North Carolina Chapel Hill, said there are two significant benefits in using platelet membranes to coat anticancer drugs.  One, the surface of cancer cells is attracted to platelets, so they stick to each other, and two, since the platelets originate from the patient own body they aren�t seen as foreign objects and therefore last longer in the blood stream.  The pseudo-platelets can circulate for up to 30 hours, comparted to about six hours for nanoscale vehicles without the coating.

�This combination of features means that the drugs can not only attack the main tumor site, but are more likely to find and attach themselves to tumor cells circulating in the bloodstream � essentially attacking new tumors before they start,� said Quanyin Hu, lead author of the paper and a Ph.D. student in the joint biomedical engineering program.

The process works by isolating platelets from a blood sample, then extracting platelet membranes which are then placed in a solution with a nanoscale gel containing the anticancer drug doxorubicin (Dox).  Dox attacks the nucleus of a cancer cell. Compacting the solution forces the gel through the membranes and creates nanoscale spheres that consist of platelet membranes with Dox-gel cores.  The surface of the spheres are then coated with the anticancer drug TRAIL, which attacks the cell membrane of cancer cells.  

Studies on mice found that using the combination drug delivery system in the form of a pseudo-platelet was significantly more effective against large tumors and circulating tumor cells than using the drugs in a nano-gel delivery system without the platelet membrane.

�We�d like to do additional pre-clinical testing on this technique,� Gu said. �And we think it could be used to deliver other drugs, such as those targeting cardiovascular diseases, in which the platelet membrane could help us target relevant sites in the body.�