PNAS: Nanoparticles could eliminate drug-eluting stents
Researchers at Massachusetts Institute of Technology (MIT) and Harvard Medical School have built targeted nanoparticles that can cling to artery walls and slowly release medicine, which could be an alternative to drug-eluting stents in some patients with cardiovascular disease, according to research published in the Jan. 18 issue of the Proceedings of the National Academy of Sciences.

The researchers predict that these nanoparticles could become a complementary approach that can be used with vascular stents, in most cases of clogged and damaged arteries, or instead of stents in areas not well suited to them, such as near a fork in the artery.

Lead investigator Omid C. Farokhzad, MD, associate professor at Harvard Medical School, reportedly achieved spatial control by screening a library of short peptide sequences and coating the outer layer of the nanoparticles with those that bound effectively to vascular antigens exposed in disease.

The researchers achieved temporal control by designing 60-nm hybrid nanoparticles with a lipid shell interface surrounding a polymer core, which was loaded with slow-eluting conjugates of paclitaxel for controlled drug release over 12 days.

"This is a very exciting example of nanotechnology and cell targeting in action that I hope will have broad ramifications," said co-researcher Robert S. Langer, PhD, David H. Koch Institute Professor at MIT in Cambridge, Mass.

Because the particles can deliver drugs over a longer period of time and can be injected intravenously, patients would not have to endure repeated and surgically invasive injections directly into the area that requires treatment, said Juliana Chan, a graduate student in Langer's lab and lead author of the study.

They are one of the first such particles that can precisely home in on damaged vascular tissue, said Farokhzad. “The nanoparticles inhibited human aortic smooth muscle cell proliferation in vitro and showed greater in vivo vascular retention during percutaneous angioplasty over nontargeted controls.”

"This technology could have broad applications across other important diseases, including cancer and inflammatory diseases where vascular permeability or vascular damage is commonly observed," added Farokhzad.