Confirmation of Peg Surface Αcyclodextrin Surface Mechanism

Abstract

αCyclodextrin (CD) is a unique molecule because of its hydrophobic interior cavity and hydrophilic exterior. This interior cavity can create inclusion complexes with a variety of hydrophobic guest molecules, including resveratrol, a hydrophobic molecule naturally found in red wine and grapes. Our specific surface sensing paradigm, CD attaches temporarily to surface bound polyethyl glycol (PEG), and releases when exposed to our model analyte, resveratrol. αCD-PEG system is a reusable hydrophobic molecule sensor, so understanding the modification mechanism behind its behavior is crucial to the optimization of the sensor. EIS analysis of this system implies removal of physioadsorbed PEG from the surface when first exposed to CD, leaving only thiol-bonded PEG to gold surface and αCD attached to PEG. This theory implies variable surface coverage, and further analysis is needed for optimal reusability.Within a flow cell, eQCM, setup, αCyclodextrin-PEG system was modified onto a gold electrode using thiol-PEG. A decrease in frequency (proportional to an increase in mass) was observed upon PEG attachment. After this modification, αCD was introduced to the system and attached to the PEG, which resulted in a decrease in mass indicated by the removal of physiosorbed PEG. After this initial decrease in mass, reversibility is achieved between resveratrol measurements and CD reloading. The supported data supports the development of a PEG:CD reusable sensor paradigm.Acknowledgements: The authors would like to acknowledge the financial support from NIH (P20 GM113131) and the Hamel Center of Undergraduate Research at the University of New Hampshire. The authors also would like to acknowledge the assistance of Dr. Halpern’s laboratory.