An apparatus for examining membrane-bound proteins in a cell can include a chamber with an insulating partition dividing the chamber into an upper well and a lower well, and a pore penetrating the insulating partition. The pore can have a size and shape so as to snugly hold a cell in place therein. The apparatus can further include circuitry for delivering a radio frequency signal to the cell. A belt electrode for delivering electrical signals to the cell can be located within the insulation partition and substantially encircling the pore. A measuring circuit for measuring cell membrane impedance to the radio frequency signal is also provided, and changes in the impedance can signal a change in state of a protein in the cell membrane.