Laurie Garrett provides a primer on the rapidly developing field of synthetic biology, or synbio:
To understand how the field of synthetic biology works now, it helps to use a practical example. Imagine a legitimate public health problem — say, how to detect arsenic in drinking water in areas where ground-water supplies have been contaminated. Now imagine that a solution might be to create harmless bacteria that could be deposited in a water sample and would start to glow brightly in the presence of arsenic. No such creature exists in nature, but there are indeed creatures that glow (fireflies and some fish). In some cases, these creatures glow only when they are mating or feel threatened, so there are biological on-off switches. There are other microorganisms that can sense the presence of arsenic. And there are countless types of bacteria that are harmless to humans and easy to work with in the lab.
To combine these elements in your lab, you need to install an appropriate software program on your laptop and search the databases of relevant companies to locate and purchase the proper DNA units that code for luminescence, on-off switches, and arsenic sensing. Then, you need to purchase a supply of some sort of harmless bacteria. At that point, you just have to put the DNA components in a sensible sequence, insert the resulting DNA code into the bacterial DNA, and test to see if the bacteria are healthy and capable of replicating themselves. To test the results, all you have to do is drop some arsenic in a bottle of water, add some of your man-made bacteria, and shake: if the water starts to glow, bingo.