Biosensor based on the directly enzyme immobilization into a gold nanotriangles/conductive polymer biocompatible coat for electrochemical detection of Chlorpyrifos in water

Organic conductive polymers have been widely used as active layers in bioelectronic devices. In this work, a novel approach to entrap enzymes directly into the conductive active layer is described, using a polysaccharide as a surfactant. The surfactant allowed the electropolymerization from a micellar media and it acted as a doping agent in the conductive polymer. Gold nanotriangles were added to the matrix in order to enhance the enzymatic product quantification. The composition and oxidation state of the biocompatible conductive layer were confirmed by infrared spectrophotometric and Raman studies. Meanwhile, the gold nanotriangles presence, distribution and electrochemical activity were studied by transmission electron microscopy, atomic force microscopy, dynamic light scattering and cyclic voltammetry techniques. The inhibition of the enzyme, due to the presence of pesticides, was used to electrochemically quantify their concentration in real water samples. The concentration was confirmed by gas and liquid chromatography. Therefore, this novel composite active layer allows building a biosensor with suitable performance for an early warning in environmental control, especially in countries highly impacted by agricultural activities.