A Schematic drawing illustrating the principle of determination of proximity between ion channels and cell-surface receptors by the patch-clamp technique. Gold nanoparticles of 30 nm diameter bound to the cell-surface receptors, here MHCI, may influence the binding properties of Pi 2 toxin. The modulation of toxin binding properties depend on the size of ligand and nanoparticle, intermolecular distance, and receptor density, as well as the receptor-channel proximity.