Abstract
Most pioneering biosensors employ a biological molecule--an enzyme, antibody, nucleic acid, or other element--to recognize sample molecules of interest. Recognition takes place via biochemical binding through hydrogen bonding, charge-charge interactions, and so forth. A secondary process, such as a colorimetric indicator reaction or the amplification of a weak bioelectric signal, informs the user of the primary molecular recognition event. A few such molecular recognition biosensors are familiar as consumer products, including glucose monitors (enzyme-based), pregnancy test strips (antibody-based), and paternity test kits (nucleic acid-based). This article describes the use and design features of modern biosensors.