Hacking Biological Computers Next?

I read an article today posted on Mercury News how researchers at Stanford have created a biological computer.  The claims this opens the doors for things such as checking for mercury levels up to and including shutting of cancer cells based on how fast they replicate.

While this all is good an promising, something I want to see, I do wonder how it will or could be abused in a similar fashion holes have been found in wireless pacemakers.  Think about it, if you could program cells to function a particular way, such as shutdown, wouldn’t you be able to make a computer that would just shutdown ANY cell after it replicates X number of times?  I see no reasons why not, the primary concern to address is transmission, if it is an easy thing (such as placing the biological computers in the drinking water supply) then it would be a high concern as you could create a biological computer that could sit dormant for a significant time then activate in a relatively short period of time in a large number of individuals.  If it is not (such as requires an injection and is short lived) then the concern is much less.

Something to think about eh?