The research team includes: Michael A. Bruckman, a postdoctoral researcher, and Lauren N. Randolph, an undergraduate student, in the Steinmetz lab; Kai Jiang, a PhD student in Yu's lab; and Leonard G. Luyt, assistant professor, and Emily J. Simpson, a PhD candidate, both at department of chemistry at Western University, in London, Ontario.
Elongated nanoparticles have a higher probability of being pushed out of the central blood flow and targeting the vessel wall compared to spheres. Further the shape allows more stable attachment to the plaque, the researchers said.
The virus surface is modified to carry short chains of amino acids, called peptides, that make the virus stick where plaques are developing or already exist. Luyt and Simpson synthesized the peptides.
"The binding allows the particle to stay on the site longer, whereas the sheer force is more likely to wash away a sphere, due to its high curvature," said Yu, an appointee of the Case School of Engineering.
The virus surface was also modified to carry near-infrared dyes used for optical scanning, and gadolinium ions (which are linked with organic molecules, to reduce toxicity of the metal) used as an MRI contrasting agent. They used optical scans to verify the MRI results.
By loading the surface with gadolinium ions instead of injecting them and letting them flow freely in the blood stream, the nanoparticle increases the relaxivityor contrast from healthy tissueby more than four orders of magnitude.
"The agent injected in the blood stream has a relaxivity of 5, and our nanoparticles a relaxivity of 35,000," said Steinmetz who was appointed by the Case Western Reserve School of Medicine.
That's because the nanorod carries up to 2,000 molecules of the contrast agent, concentrating them at the plaque sites. Secondly, attaching the contrast agent to a nanoparticle scaffold reduces its molecular tumb
|Contact: Kevin Mayhood|
Case Western Reserve University