From a reader:

Jonah,
Being a Jurassic Park fan, the following is scary but neat:
From the Sun-Sentinal:
“Another safeguard scientists are designing to provide total control over artificial cells is to make their lives dependent on chemicals that do not exist in the environment. Withdrawing the critical chemicals would result in the death of the cells, particularly if they should escape into the environment.”
Evil Laugh.
Best
pj