Viral Battery

Scientists at the MIT might be on a breakthrough here.

Researchers at the Massachusetts Institute of Technology have "trained" viruses in a lab to create a miniature battery.
By manipulating a few genes within the virus, researchers were able to get the organism to grow and then assemble itself into a functional electronic device. They hope to be able to build a battery that could be as small as a grain of rice. [link]

A grain of rice. Now, it was hardly nano eh! But the brighter side is if they could also replicate as viruses, that, would be something.

I buy a grain of battery and it multiplies out into a petridish full of batteries overnight..