Patent ID: 8426148

Claim:
A label-free method for GPCR signaling pathway determination, the method comprising: immobilizing live cells on a resonant waveguide grating (RWG) biosensor; contacting the immobilized live cells with a substance that elevates intracellular cAMP and activates protein kinase A in the live cells; contacting the substance-contacted live cells with a GPCR ligand; detecting and comparing the GPCR ligand-induced biosensor response of the live cells in the presence and absence of the substance; and determining the signalling pathways of the GPCR activated by the ligand, wherein the substance-induced inhibition of the GPCR ligand-induced response indicates that the GPCR signals via G αs pathway, the substance-induced partial suppression of the GPCR ligand-induced response indicates that the GPCR signals via a G αq pathway, and the substance-induced potentiation of the GPCR ligand-induced response indicates that the GPCR signals via a G αi pathway, wherein the response is a dynamic mass redistribution (DMR) signal measured by the resonant waveguide biosensor, and the substance is a probe molecule to differentiate all classes of signalling mediated through the GPCR.