What Were They Thinking?
Since this is fairly uncharted territory, the eggheads figured they'd better start small. The robo-leech is only able to do simple calculations, but it's still a solid first step into bio-organic computer components. In the decade since, scientists have continued research into making living things into computer parts. Take, for example, the gold-plated microbes that scientists built to act as humidity sensors in moisture-sensitive equipment. They're four times more accurate at detecting moisture than solely electronic sensors.
Via BBC News
We're not even to the creepy (or is it creepiest?) part of this whole scheme. They built this thing specifically so it could think for itself and, if it didn't know the answer to a question, to figure it out for its damn self. According to one of its creators, "Ordinary computers need absolutely correct information every time to come to the right answer. We hope a biological computer will come to the correct answer based on partial information, by filling in the gaps itself."
Yeah, that makes sense.
We won't have to worry about rogue A.I.s becoming sentient one day if they're already living, thinking things. Then it's just a certainty.