Scientists are attempting to neutralize low-density lipoproteins (LDL), the kind that can clog arteries, by creating tiny particles that mimic high-density lipoproteins (HDL), which carry cholesterol away and clean up plaque sites. Artificial HDL nanoparticles use a gold core, which can be detected by imaging technologies, and a surface coated with fats and proteins that can bind to the cholesterol to ferry it away. The manufactured particles may eventually prevent strokes and heart attacks, and can be used in diagnosing patients. A potential downside? Though gold is a nontoxic element, scientists are concerned about what could happen if gold nanoparticles accumulated in the body over time.