Session: Advances in Electrochemistry:

A biosensor is a device that can determine the concentration or presence of chemicals. Neurotransmitters and neuropeptides are examples of chemical signals in the brain that produce responses or functions throughout the organism. Certain excitatory neurotransmitters and neuropeptides can be measured by Methylene blue (MB), a synthetic dye that stains to negatively charged cell components like nucleic acids and aptamers. In this work, we do aptamer modifications because they possess the advantage of binding to any given target molecule and, when they bind, they undergo conformational changes, which is where MB comes into play. This project focuses on the modification of the surface of Gold (Au) and Highly Oriented Pyrolytic Graphite (HOPG) electrodes using methylene blue as a redox label probe for the detection of neurotransmitters and neuropeptides in aptamer-modified electrodes. Electrochemical Impedance Spectroscopy (EIS) was used to understand the adsorption properties of molecules that stick to the surface of the electrode and Atomic Force Microscopy (AFM) was used to measure the topography of the electrodes before and after the aptamer modification. As results, we were able to prove that AFM cannot monitor the changes on the surface of the Au electrodes with the different modifications due to the roughness of the surface, and that, electrochemically, the capacitance of the gold electrode decreases at higher concentrations of NPY. Different molecules such as dopamine (DA) and epinephrine (EPI) are also of interest to determine if the sensor system has the same selectivity with different types of molecules. The results that we obtain give us a better understanding of the use of these techniques for the monitoring of biomolecules.

Lyza M Martinez

Undergraduate research student, Ana G. Mendez University, Gurabo Campus

Appearances