At the local office supply store, a roller-ball ge

At the local office supply store, a roller-ball gel pen will cost you about 50 cents. With a little tinkering, researchers are taking that same pen and using it to measure glucose levels.

Nano-engineers at the University of California, San Diego have invented a technique that turns cheap pens into dispensers for do-it-yourself sensors. They replace the regular gel with a custom biochemical ink that can measure specific chemicals.
http://money.cnn.com/2015/03/10/technology/di...st+News%29

....when consumer demand is great enough.....