Integration of Cyclodextrin-Mediated Surfaces with Electrochemical Flow Cell

Abstract

Cyclodextrin (CD) is a widely used molecule in surface modification and chemical sensing. Cyclodextrin consists of a hydrophobic cavity and hydrophilic exterior, which can form host-guest inclusion complex with hydrophobic molecules. The host-guest complex can be used for recognition and detection. The working electrode surfaces are modified with adamantane or poly ethyl glycol (PEG) via thiol-based click chemistry, and further complexed with a CD intermediate to create our sensor surfaces. The modified surfaces are integrated with a flow cell, where solutions are pumped through multiple electrodes simultaneously. Flow cell allows us to reduce the required test volume and evaluate multiple surfaces simultaneously. We use Electrochemical Impedance Spectroscopy to measure changes in the surface. We will discuss appropriate equivalent circuit models to fit charge transfer resistance, capacitance, and Warburg impedance over multiple layers to achieve accuracy. Hydrophobic analytes such as cortisol and resveratrol are measured with flow cell and clear trend of capacitance/ impedance vs concentration is discovered. Our goal is to reproducibly monitor surface changes and measure hydrophobic analytes in unknown sample solutions.