Posted: June 12, 2007

Antibody drags nanoparticle Into lung cells

(Nanowerk News) Cells use several methods to transport molecules through their cell membranes, most of which depend on a specific recognition event between those molecules and receptors on the cell surface. Now, researchers at the Sidney Kimmel Cancer Center have taken advantage of one of these receptors, found only on the surface of blood vessels in the lung, to transport nanoparticles specifically into lung tissue. The investigators have even been able to image this transport process taking place.
Jan Schnitzer, M.D., principal investigator of a National Cancer Institute Platform Partnership, and his collaborators first identified a molecule on lung endothelial cells—the cells that line blood vessels—that acts to trigger a process known as caveolae-mediated transport. Caveolae are horseshoe-shaped indentations in the cell membrane that surround transportable molecules once they bind to specific cell-surface molecules. In their stage of this project, the investigators identified a protein called aminopeptidase P (APP) as being one of these triggering molecules. They then developed a monoclonal antibody that binds only to APP and attached that antibody to gold nanoparticles.
Imaging experiments, using several different techniques, showed conclusively that this antibody was able to target lung tissue specifically. When the antibody bound to its target, cells rapidly took up the antibody and the attached nanoparticles. Whole-body imaging experiments showed that only lung tissue took up the antibody-nanoparticle construct. The researchers published their results in the journal Nature Biotechnology ("Live dynamic imaging of caveolae pumping targeted antibody rapidly and specifically across endothelium in the lung").
Source: National Cancer Institute