Pseudocolored scanning electron microscope images of platelet-membrane-coated nanoparticles (orange) binding to the lining of a damaged artery (top) and to MRSA bacteria (bottom). Each nanoparticle is approximately 100 nanometers in diameter, which is one thousand times thinner than an average sheet of paper. Image credit: Zhang Research Group, UC San Diego Jacobs School of Engineering.
While a great variety of nanoparticles have been developed that can deliver medicine deep inside the body, their targeting abilities can be quite limited and often rely on integrating unique antibodies for individual patients. Researchers at University of California, San Diego are now reporting in journal Nature on the creation of a polymeric nanoparticles that are encapsulated within the plasma membrane of circulating platelets, which naturally seek out and cling to injured parts of the body. These nanoparticles, which have the entire set of characteristics present within platelet membranes, are able to safely avoid the immune system, permitting them to have unprecedented access within the body.
The particles are made by harvesting human platelets, breaking them apart to only gather their membranes. These are then attached to the polymeric nanoparticles, effectively cloaking the contents from being noticed by the immune system.
The team tested the new nanoparticles on rats with damaged arteries, delivering docetaxel that prevents scar development. The findings showed that the drug settles within the damaged tissue in greater quantities and helps with healing of the vessels. They also used the nanoparticles to deliver antibiotics to attack infections afflicting many parts of the body, which demonstrated great success in a lab study.
From the study abstract in Nature:
Compared to uncoated particles, the platelet membrane-cloaked nanoparticles have reduced cellular uptake by macrophage-like cells and lack particle-induced complement activation in autologous human plasma.
The cloaked nanoparticles also display platelet-mimicking properties such as selective adhesion to damaged human and rodent vasculatures as well as enhanced binding to platelet-adhering pathogens. In an experimental rat model of coronary restenosis and a mouse model of systemic bacterial infection, docetaxel and vancomycin, respectively, show enhanced therapeutic efficacy when delivered by the platelet-mimetic nanoparticles. The multifaceted biointerfacing enabled by the platelet membrane cloaking method provides a new approach in developing functional nanoparticles for disease-targeted delivery.
Nature: Nanoparticle biointerfacing by platelet membrane cloaking…
