Contents

13 October 1989
Vol 246, Issue 4927

About The Cover

Living nonadherent P388D1 cells (from murine lymphoid neoplasm), stained here with a red fluorescent dye, are retained in wells (50 m square and 50 m deep) etched into the surface of a potentiometric silicon biosensor. The sensor measures metabolic rates, which are affected by a variety of biological and chemical agents. See page 243. [Photograph by J. C. Owicki and K. M. Kercso, Molecular Devices Corporation, Menlo Park, CA 94025]