Covering iGEM is hard: choosing presentations based on what sounds cool won?t get you very far, because almost everything sounds cool. Who would say no to a microbial mass production system for blood (Berkeley) or RNAi components strung together to create a way to cure cancer (Princeton)? But with most of the projects so conceptually ambitious, one of the judges told me, sifting through them really requires squaring what was originally planned with what got accomplished.

Ten or so groups have made chemical sensors, for example, but there's a huge range in how well they built their systems, said James Brown, who is mentoring the Cambridge University group this year. He pointed me to MIT's mercury sensor, which also acts as a filter that can clean contaminated water. They used induction with AHL, a quorum-sensing molecule often used in biosensors, to activate two constructs, one of which reports mercury while the other binds it.

Drew Endy of MIT, who is in charge of the judging with Chris Voigt from UCSF, told me that an idea that makes compelling use of biotechnology is worth a lot, but of course, that?s coupled with what a team is able to deliver. Another criteria of judges is what a team gives back to the community in biological parts that can be added to the Registry (which I described in my post last night), but there's a huge range in whether groups end up contributing.