Qcm Detection of Membrane Protein-ligand Interactions Using Cell-derived Liposomes

We present a novel QCM (quartz crystal microbalance) sensor for detecting interactions between membrane proteins and their ligands using liposomes derived from human cells. The liposome production is induced by stimulating human lymphocyte cells with NaB (sodium butyrate). Liposomes produced in this method already retain specific membrane proteins that were expressed in the host cells. The membrane proteins on the liposomes maintain their original structures and functions. In this research, we applied the cell-derived liposomes to the detection of membrane protein-ligand interactions as follows. First, liposomes having BCR (B-cell receptor) were derived from human lymphocyte cells, Ramos. Next, the liposomes were separated from the cells by filtration and micronized by sonication. Then, the liposomes were immobilized on the surface of a QCM sensor chip using cell-anchoring molecules. Several experiments demonstrated that ligand detection is achieved by frequency reduction with application of the antibody against BCR.