Gold nanoparticles: Poly(diallyldimethylammonium chloride)-carbon nanotubes composites as platforms for the preparation of electrochemical enzyme biosensors: Application to the determination of cholesterol

► AuNPs/PDDA/MWCNTs nanocomposites were used for the construction electrochemical biosensors. ► Suitability of single and bienzyme biosensors was demonstrated, taking cholesterol as analyte. ► This platform allows to use extremely simple enzymes immobilization with no need of covalent bonds. ► The use of estabilized strategies to avoid potential interferences in real samples is feasible. ► Human sera spiked with cholesterol at physiological levels were analyzed with good results.