A master thesis from Aalborg University
Development of an affinity-based impedimetric biosensor using gold screen-printed electrodes
Author(s)
Term
4. term
Education
Publication year
2021
Submitted on
2021-06-03
Pages
80 pages
Abstract
In this report, the use of screen-printed electrodes as a biosensing platform was studied by electrochemical techniques. Different surface cleaning methods are compared and all the functionalization steps are characterised using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. Ferrocaynide redox couple and two ferrocene derivatives, namely ferrocenecarboxylic acid and 1-1'ferrocenedimethanol, were used to study the faradaic behaviour of the biosensor. Synthesis of 11-mercaptoundecanoic acid and mixed 11-mercaptoundecanoic acid/ 6-mercapto-1-hexanol SAMs is performed from solution. An initial optimization step was required to minimize the damage produced by the solvent on the working electrode. Different incubation times and ethanol concentrations were tested. Anti-NGAL monoclonal antibodies are attached to the monolayer surface through a two-step coupling reaction utilizing EDC as a cross-linker and NHS as a catalyst. The etching effect of cyanide ions on gold electrodes is observed when EIS and CV were employed in ferro-/ferricyanide solution. The electrostatic interactions between the redox probes and the electrode surface at different steps during functionalization are determined to have a great impact on the recorded EIS spectra. Furthermore, calibration curves were obtained by plotting the changes in charge transfer resistance after incubation with different AG concentrations. The LOD, LOQ and the dynamic linear range are determined for two biosensing approaches.
Keywords
Documents
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