A method is provided for determining, the presence and concentration of an analyte by contacting the sample with a solution comprising: magnetic beads, a capture probe capable of binding the analyte, a reporter probe and cellulose, whereby, if the analyte is present, an MB-analyte-reporter-cellulase sandwich is formed; and then contacting the solution comprising the sandwich with an electrode covered with an electrically insulating layer comprising or consisting of cellulose and/or a cellulose derivative, wherein the MB-analyte-reporter-cellulase sandwich leads to degradation of the insulating layer thereby causing a measurable change in electrical properties at the electrode surface, wherein the change in electrical properties is a function of the amount of analyte in the sample. Devices and biosensor applying the method are also provided.