SINGLE CELLS AS BIOSENSORS FOR CHEMICAL SEPARATIONS

A biosensor system based on the response of living cells was demonstra ted that can detect specific components of a complex mixture fractiona ted by a microcolumn separation technique. This system uses ligand-rec eptor binding and signal-transduction pathways to biochemically amplif y the presence of an analyte after electrophoretic separation. The tra nsduced signal was measured by means of two approaches: (i) fluorescen ce determination of intracellular calcium concentrations in one or mor e rat PC-12 cells and (ii) measurement of transmembrane current in a X enopus laevis oocyte microinjected with messenger RNA that encodes a s pecific receptor. This analysis system has the potential to identify b iologically active ligands present in a complex mixture with exception al sensitivity and selectivity.