Nanogen, of San Diego, Calif., has received US Patent No. 6,867,048, "Multiplexed active biologic array." The patent covers a method of addressing and driving an electrode array that includes the step of addressing one or more electrodes within the array using a plurality of row and column lines. The patent also covers a method where a value corresponding to a voltage is stored in a local memory associated with each electrode. The addressed electrodes are then driven at the voltages corresponding to the stored values.