The particles that ferry cholesterol through the bloodstream are popularly known as “bad” or “good”: bad if they deposit cholesterol on vessel walls, potentially clogging them; good if they carry the cholesterol on to the liver for excretion.

Now scientists have created tiny particles in the laboratory that mimic those good carriers, scooping up the cholesterol before it can grow into dangerous deposits of plaque. The surfaces of these new particles are coated with fats and proteins so they can bind tightly with the sticky cholesterol to transport it through the bloodstream.

The particles may someday be important in treating cardiovascular disease, said Dr Andre Nel, chief of the division of nanomedicine and director of the Center for Environmental Implications of Nanotechnology at the University of California, Los Angeles.

“Researchers have endowed these artificial particles with the same properties as natural particles that circulate in the blood,” called high-density lipoproteins, or HDL, he said. The artificial carriers can clean up sites where accumulating plaques can otherwise cause rupture, leading to strokes and heart attacks.

The particles may be useful not only in cardiovascular therapy, but also in diagnosis. The researchers have put gold and other metal cores at the center of the particles, Nel said, so they show up well in medical imaging. Such imaging could be used, for example, to monitor plaques as they build up in blood vessels.

At the Chicago campus of Northwestern University, artificial HDL nanoparticles have been designed by Dr C Shad Thaxton, assistant professor in the urology department, and Dr Chad A Mirkin, professor and director of the International Institute for Nanotechnology at the university's Evanston campus. They have founded a company, AuraSense, to commercialise the technology.

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