Development and application of cell-based biosensors

Biosensors incorporate a biological sensing element that converts a change in an immediate environment to signals conducive for processing. Biosensors have been implemented for a number of applications ranging from environmen tal pollutant detection to defense monitoring. Biosensors have two intrigui ng characteristics: (1) they have a naturally evolved selectivity to biolog ical or biologically active analytes; and (2) biosensors have the capacity to respond to analytes in a physiologically relevant manner. In this paper, molecular biosensors, based on antibodies, enzymes, ion channels, or nucle ic acids, are briefly reviewed. Moreover, cell-based biosensors are reviewe d and discussed. Cell-based biosensors have been implemented using microorg anism, particularly for environmental monitoring of pollutants. Biosensors incorporating mammalian cells have a distinct advantage of responding in a manner that can offer insight into the physiological effect of an analyte. Several approaches for transduction of cellular signals are discussed; thes e approaches include measures of cell metabolism, impedance, intracellular potentials, and extracellular potentials. Among these approaches, networks of excitable cells cultured on microelectrode arrays are uniquely poised to provide rapid, functional classification of an analyte and ultimately cons titute a potentially effective cell-based biosensor technology. Three chall enges that constitute barriers to increased cell-based biosensor applicatio ns are presented: analytical methods, reproducibility, and cell sources. Po ssible future solutions to these challenges are discussed. (C) 1999 Biomedi cal Engineering Society. [S0090-6964(99)01406-X].