Patching a damaged heart is on the agenda again, with nanoscale-featured scaffold material this time: "When you suffer a heart attack, a part of your heart dies. Nerve cells in the heart's wall and a special class of cells that spontaneously expand and contract - keeping the heart beating in perfect synchronicity - are lost forever. [At present] surgeons can't repair the affected area [but the] best approach would be to figure out how to resuscitate [it] ... scientists turned to nanotechnology. In a lab, they built a scaffold-looking structure consisting of carbon nanofibers and a government-approved polymer. Tests showed the synthetic nanopatch regenerated natural heart tissue cells - called cardiomyocytes - as well as neurons. In short, the tests showed that a dead region of the heart can be brought back to life. ... the engineers employed carbon nanofibers, helical-shaped tubes with diameters between 60 and 200 nanometers. The carbon nanofibers work well because they are excellent conductors of electrons, performing the kind of electrical connections the heart relies upon for keeping a steady beat. ... In tests with the 200-nanometer-diameter carbon nanofibers seeded with cardiomyocytes, five times as many heart-tissue cells colonized the surface after four hours than with a control sample consisting of the polymer only. ... The scaffold works because it is elastic and durable, and can thus expand and contract much like heart tissue. ... It's because of these properties and the carbon nanofibers that cardiomyocytes and neurons congregate on the scaffold and spawn new cells, in effect regenerating the area."