It is still a challenge for scientists to develop a good nano-scale battery, which is why nano-scale devices are still fueled by energy sources that are much bigger than the devices themselves. One of the key problems is how to build such a small battery, and NASA has been looking at biological molecules that have self-assembling properties in order to overcome this barrier.
A group of researchers at NASA has been working on a protein called ferritin, which has the unique ability to carry either a positive or negative charge. The protein is also capable of self assembling into a uniform nanolayer form. NASA sees potential in the material, suggesting that it is relatively easy to create a layer of ferritin and then cover it with another layer of the opposite charge. The outcome is a capacitor just a few nm thick, which NASA believes is stable, robust, and can be produced easily and quickly. In fact, NASA has already applied for a patent for the device.