The foundation of nucleic acid–based biosensors relies on a transducer capable of
monitoring a change in the nucleic acid’s structure occurring after exposure to a target
chemical. These structural changes are brought on either by the mutagenic nature of the
chemical, resulting in mutations, intercalations, and/or strand breaks, or by the chemical’s
ability to covalently or noncovalently attach to the nucleic acid. Immobilizing
the nucleic acid as a recognition layer on the transducer surface forms the biosensor,
and detection of the chemically induced nucleic acid conformational change is then
typically achieved electrochemically (i.e., a change in the current) or less so through
optical or other means