Development and characterization of bi-functional and nanoestructured Au-Pt surfaces and its application in biosensors for pesticides

• Grant number: 10/03813-4
• Support type: Regular Research Grants
• Duration: August 01, 2010 - July 31, 2012
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Analytical Chemistry
• Principal researcher: Sergio Antonio Spinola Machado
• Grantee: Sergio Antonio Spinola Machado
• Home Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Assoc. researchers: Ivana Cesarino ; Lívia Flório Sgobbi

Abstract

The aim of this project is to develop and to characterize bifunctional surfaces, composed by gold nanoparticles electrodeposited on Pt surface and covered by alkanethiol self-assembled monolayer for the design of a amperometric biosensor, based in the inhibition of acetylcholinesterase inhibition for the detection of pesticides in food. The polycrystalline Pt surface will be modified by the electrodeposition of Au nanocrystals from a tetrachloroaurate electrolyte by linear sweep voltammetry. These modified surfaces will be characterized by electrochemical (cyclic voltammetry, electrochemical impedance spectroscopy) and by atomic force microscopy to determine the size and distribution of nanoparticles on the surface, as well as the exposed Pt area. In a second stage, the gold nanoparticles will be covered with self-assembled monolayers of cystamine aiming their preparation for enzyme immobilization. This SAM coverage will be analyzed by cyclic voltammetry and by electrochemical impedance spectroscopy, as well as by atomic force microscopy. Finally, on the SAM the enzyme acetylcholinesterase will be immobilized for the biosensor preparation. The enzymatic reaction product, the thiocholine, will be determined on the platinum exposed surface, with the aim of take advantage of Pt enhanced catalytic activity, which can improve the biosensor sensitivity. This biosensor will be applied in the determination of carbamates pesticides in foodstuffs as tomatoes, cabbage leaves and strawberries in natura or spiked. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

COELHO, DYOVANI; MACHADO, SERGIO A. S. New contribution in the study of phase formation in mixed alkanethiol self-assembled monolayers: a powerful tool for transducers design. Electrochimica Acta, v. 142, p. 191-201, OCT 1 2014. Web of Science Citations: 6.