Author : Hamid Feyzizarnagh
Publisher :
ISBN 13 :
Total Pages : 94 pages
Book Rating : 4.:/5 (971 download)
Book Synopsis Characterization and Modeling of Self-assembled Monolayers for Antifouling and Mediatorless Biosensors by : Hamid Feyzizarnagh
Download or read book Characterization and Modeling of Self-assembled Monolayers for Antifouling and Mediatorless Biosensors written by Hamid Feyzizarnagh and published by . This book was released on 2015 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of nanomaterials to improve biosensor performance has gained a great deal of interest over the past decade. This dissertation research aims to explore the development of antifouling self-assembled monolayers (SAMs) to prevent non-specific adsorption on the working electrode surface of electrochemical sensors. A few organic compounds were studied using electrochemical impedance spectroscopy (EIS) and 3,6-dioxa-8- mercaptooctan-1-ol (DMOL) was selected for this purpose. It has two ether groups in its chain, which are believed to hinder the protein adsorption on the gold electrode surface because of the formation of a hydration layer near the surface through hydrogen bonding between water and DMOL. Another key point in the selection of DMOL is the functional group at the end of its chain that can bind to a gold surface in order to produce a SAM. An aptamer-based hemoglobin sensor modified with DMOL SAM was tested with samples containing other interfering blood proteins and molecules by performing single frequency EIS. Results showed DMOL's ability to reduce the adsorption of non-specific molecules. It was also demonstrated that DMOL was not interfering with the immobilization of the sensing element (aptamer) and the sensing of the target molecules (hemoglobin). Another goal of the research presented here is to investigate the utilization of peptide nanotubes, another interesting class of nanomaterials that mediate the electron transfer between the electrode and the electroactive sites of receptors without any need of using chemical mediators. This avoids the drawbacks of using chemicals such as hydroquinone, which may be toxic to sensing elements or may interfere with the electrochemical reaction of interest. Results obtained from this part suggested that an H2O2 sensor interface modified with peptide nanotubes containing horseradish peroxidase (HRP) shows a comparable electron transfer capability with that of typical chemical mediators. Finally an equivalent circuit modelling approach was proposed, and it was applied to the experimental data obtained from the electrochemical impedance spectroscopy of mercaptoalkanoic acids. A modification to the classical Warburg element in the equivalent circuit was made which shows much better fitting of experimental data than the circuit containing the conventional Warburg element. A non-linear least square algorithm was carried out using the Microsoft Excel Solver add-in to minimize the error (Chi-squared) to fit the model to the experimental data.
