Aptamer-Modified Microelectrodes for the Electrochemical Impedance Spectroscopy Detection of Neuropeptide Y

Abstract

The design novel biosensors is a broad field including a wide range of applications including medical diagnostics and environmental monitoring. Small sizes of the electrodes have advantages used for selective identification of a biological target, such as voltammetric time scales, lower background noise and higher spatial resolution. Platinum and Carbon nanofiber has been some promising materials for fabrication of electrodes because of their electrical conductivity, chemical stability and high surface area. The intended application is to the possibility to create point of care diagnostics for monitoring the health of astronauts. Neuropeptides are short amino acid chains that are synthesized in the soma and dendrites, and they are stored in large dense core vesicles until released from nerve endings as well as from dendrites. Also, it’s not recycled and there is no reuptake system, but they are broken by peptidases, which require the cell to always synthesize new molecules to replace them by sending them from the soma to the nerve endings and dendrites. Other small neurotransmitters are normally released together with neuropeptides; therefore, it is essential to develop a technique for their detection as selective as possible and to have a strategy to cancel out the signal exerted by other neurotransmitters. The structural similarity between neuropeptides makes their detection impossible using common electrochemical techniques. Their study is currently done measuring the expression of neuropeptides in-vitro or using microdialysis coupled with mass spectrometry, which gives temporal resolution of tens of minutes. In this project, we have developed a modification protocol that reproducibly adds highly selective aptamers to the microelectrodes and the adsorption of neuropeptide Y differentially detected using microelectrodes. Based on the results, changes in concentration due to the release and absorption of neuropeptide Y can be followed with continuous electrochemical impedance measurements using microelectrodes, with the specificity provided by the used of aptamers in the surface of the microelectrodes.