From The Harvard Gazette:
Researchers at Harvard and Princeton universities have taken a crucial step toward building biological computers, tiny implantable devices that can monitor the activities and characteristics of human cells. The information provided by these “molecular doctors,” constructed entirely of DNA, RNA, and proteins, could eventually revolutionize medicine by directing therapies only to diseased cells or tissues.
Evaluating Boolean logic equations inside cells, these molecular automata will detect anything from the presence of a mutated gene to the activity of genes within the cell. The biocomputers’ “input” is RNA, proteins and chemicals found in the cytoplasm; “output” molecules indicating the presence of the telltale signals are easily discernable with basic laboratory equipment. Benenson and his colleagues demonstrate in their Nature Biotechnology paper that biocomputers can work in human kidney cells in a culture.
More here.