Disclosed herein is a multiplex microarray having serially attached non-functionalized biomolecules attached to a polymer coating covering each electrode of an array of electrodes for assays and a method of making the multiplex microarray. The method comprises serially blocking the electrodes of the microarray with a blocking protein, electropolymerizing pyrrole or a functionalized pyrrole on the electrodes where the biomolecule is not present during polymerization, exposing the microarray to a biomolecular solution containing a non-functionalized biomolecule for attachment to the polymer coating, and then repeating the steps to form the multiplex microarray.