The paper-like quality of the battery combined with the structure of the nanotubes embedded within gives them their light weight and low cost, making them attractive for portable electronics, aircraft, automobiles, and toys (such as model aircraft), while their ability to use electrolytes in blood make them potentially useful for medical devices such as pacemakers. The medical uses are particularly attractive because they do not contain any toxic materials and can be biodegradable; a major drawback of chemical cells.^[3] However, Professor Sperling cautions that commercial applications may be a long way away, because nanotubes are still relatively expensive to fabricate. Currently they are making devices a few inches in size. In order to be commercially viable, they would like to be able to make them newspaper size; a size which, taken all together, would be powerful enough to power a car.^[4]