Preparation and characterization of bifunctional-nanostructured surfaces of Au-Pt obtained via templates for application in sensors and biosensors

Abstract

In the present project proposes to develop and characterize bifunctional surfaces, composed of gold nanoparticles electrodeposited on platinum assisted by templates and coated with layers of self-assembled alkanethiols for the preparation of amperometric biosensors. The surface of polycrystalline platinum electrode is initially modified by electrodeposition of Au nanostructures assisted by template, electrodeposited from an electrolyte containing tetracloroaurato by linear sweep voltammetry. These modified surfaces are characterized by electrochemical techniques (cyclic voltammetry, impedance spectroscopy) and techniques of atomic force microscopy to determine the size and distribution of the gold nanoparticles on the surface, and the exposed area of platinum. Due to the considerable increase in the electroactive area of the electrode test will be electrocatalytic activity of the modified electrode with respect to the compounds of analytical interest. In a second step, the gold nanoparticles are coated with layers of self-assembled alkanethiol (cystamine) aimed at preparing the surface for the immobilization of the enzyme. This coverage will be analyzed by electrochemical techniques (cyclic voltammetry and electrochemical impedance spectroscopy) and by atomic force microscopy. Finally, the layer of self-organized cystamine is immobilized enzyme glucose oxidase, lactate oxidase, and cholesterol oxidase to prepare a biosensor. The product of the enzymatic reaction, hydrogen peroxide (H2O2) will be determined in the platinum surface, with the goal of using the catalytic properties of this surface to improve the sensitivity of the biosensor. (AU)