Dynamic mass redistribution: a novel physiological signal of cells for cell systems biology and pharmacology

This article presents a brief overview of label-free optical biosensor-based cell assay technologies. Theoretical analysis suggests that a resonant waveguide grating (RWG) biosensor detects ligand-induced dynamic mass redistribution (DMR) within the bottom portion of an adherent cell layer. Pharmacological studies suggest that the DMR signal can serve as a novel physiological readout for monitoring receptor activation, and examining ligand pharmacology. Chemical biology studies support the hypothesis that the DMR signal is an integrated response that consists of contributions from many cellular events induced by the ligand, thus providing alternative means to study cell systems biology. Orthogonal confirmations using conventional cell biology approaches have led to identifying specific cellular event(s) that dominate the DMR signals observed for three classes of receptors: epidermal growth factor receptor, Gq-coupled receptors and Gs-coupled receptors.