Our computers and digital devices keep getting smaller even while growing increasingly more robust. By comparison, the batteries that power them remain stubbornly unwieldy (and in some cases even prone to exploding).

This is one reason that Craig Arnold‘s research is especially fascinating. One of the aims of Arnold’s research is to create tiny batteries and other energy storage devices that can be implanted in the body or used to power featherweight sensors.

Arnold, an assistant professor in Princeton’s department of mechanical and aerospace engineering (which, in case you missed the news, was recently ranked No. 1 in the nation in a scholarly index), uses a laser direct-write printer to lay down energy-storing patterns with a lithium “ink.”

But that is not all Arnold can do with laser direct-write printing. Check out the image on this blog entry. It is a little faint, but you should be able to see that Arnold printed the Princeton University shield, using fluorescent E. coli bacteria as “ink,” onto a glass slide. How cool is that?

The current issue of the Materials Research Society Bulletin, which Arnold guest-edited with Alberto Piqué, notes

that laser direct-write printing can be used to make semiconductors, to engineer tissue, to create cell-based sensors, or to develop pharmaceuticals.

In the biology arena, Arnold is collaborating with synthetic biology pioneer Ron Weiss, who is working to create “bio-bricks” — bits of DNA-powered circuits — that are modular and that could one day be fitted together to manufacture such miracles as new pancreatic cells for people with diabetes or special patches that mend broken spinal cords.

The entire MRS Bulletin issue on laser direct-write processing can be purchased online. You can also read more about Arnold’s battery research in last week’s Princeton Alumni Weekly.