Herein we describe the effect of surface chemistry method for rapid, label free and direct electrochemical detection of microbiological diseases in a long amplicon sequence. Electrochemical Impedance Spectrometry (EIS) was used as signal transduction. E. coli amplicon was used as model case. Hybridization detection was performed by using several surface chemistry methods including, adsorbtion, carbodiimide chemistry, self-assemble monolayer (SAM), polypyrrole polymerization, polylysine coating, silane mediated and gold nanoparticles (AuNP) at disposable graphite (DGE) and gold (AuE) electrode surfaces. Designed genosensors' selectivities and the detection limits were compared to determine optimum pathogen detection. AuNP modified surface was chosen as optimum sensor at the detection limit of E. coli amplicon was 160.3 pM and sensor sensitivity based on Full Match/Non Complementary (FM/NC) ratio of 6.3. (C) 2016 The Electrochemical Society. All rights reserved.