One can pipette out a controlled concentration of a reagent onto one or a few cells inside a dish, without affecting the other cells. All this is done on the microscope so you can record the cell reaction and get quantitative data.The adjacent cells can serve as internal controls or can be used for repeats of the experiment. The device also has many channels, allowing you rinse the cell after exposure then expose it to other reagents and even mix the reagents in the different channels as you want. Check here to get to the webinar or see how to try BioPen with your own sample!