There are provided methods, and devices for assaying for a binding interaction between a protein, such as a monoclonal antibody, produced by a cell, and a biomolecule. The method may include retaining the cell within a chamber having an aperture; exposing the protein produced by the cell to a capture substrate, wherein the capture substrate is in fluid communication with the protein produced by the cell and wherein the capture substrate is operable to bind the protein produced by the cell; flowing a fluid volume comprising the biomolecule through the chamber via said aperture, wherein the fluid volume is in fluid communication with the capture substrate; and determining a binding interaction between the protein produced by the cell and the biomolecule.