DNA and RNA molecules can fold into a variety of different structures and shapes. For instance, complementary DNA molecules can bind with each other to form double-stranded molecules; self-complementary sequences can fold back to form hairpin loops, etc. It is possible to design molecular structures which can be reversibly switched between several alternative structures, some of which may have a particular function. Such switchable structures can find use as mechanical actuators, motors, sensors and even computational elements.

Biochemical processes such as DNA hybridization, enzymatic catalysis, or gene transcription can be exploited to implement biomolecular analogues of electronic logic circuits and signal processing. For instance, the production or release of certain biomolecules can be made dependent on the evaluation of "diagnostic" computational rules. The realization of artificial biochemical circuits holds great promise for the development of advanced biosensors, but also for re-programming of biological systems ("synthetic biology").