This review present a critical comparison of the electrochemical behavior and analytical performance ofglassy carbon electrodes (GCE) modified with carbon nanotubes (CNTs) dispersed in different polymers:polyethylenimine (PEI), PEI functionalized with dopamine (PEI-Do), polyhistidine (Polyhis), polylysine(Polylys), glucose oxidase (GOx) and double stranded calf-thymus DNA (dsDNA)