AFM and Electrochemical Analysis of Different Biomolecules Using Npy-Specific Aptamer Modified Electrodes

Abstract

Neurotransmitters and neuropeptides are chemical signals in the brain that produce responses or functions throughout the organism. Measurements of neurotransmitters are important to understand some mechanisms of how they are released off the cell. Different biomolecules can be measured with gold (Au) electrodes because it is a ductile and malleable metal that can detect small changes and can be easily modified. In this work, we use Neuropeptide Y (NPY) specific aptamer to modify the electrodes to take advantage of the binding with NPY molecules that produce conformational changes. We also study Dopamine (DA) and Norepinephrine (NE) because they corelease with NPY and we can monitor the electrochemical difference between these biomolecules. Those modifications and detection can be monitored using Electrochemical Impedance Spectroscopy (EIS) to understand the adsorption properties of molecules that stick to the surface of the electrode and Atomic Force Microscopy (AFM) to measure the topography of the electrodes before and after the aptamer modification. Electrochemical results showed that the capacitance of the Au electrode decreases at higher concentrations of NPY. AFM results showed small changes on the surface of the Au electrodes with the different modifications due to the roughness of the surface. The results obtained give us a better understanding of the use of these techniques for the monitoring of biomolecules.