Electrografting a Hybrid Bilayer Membrane via Diazonium Chemistry for Electrochemical Impedance Spectroscopy of Amyloid-β Aggregation

Abstract

Herein, a novel hybrid bilayer membrane is introduced as a platform to study the aggregation of amyloid-β1–42 (Aβ1–42) peptide on surfaces. The first layer was covalently attached to a glassy carbon electrode (GCE) via diazonium electrodeposition, which provided a highly stable template for the hybrid bilayer formation. To prepare the long-chain hybrid bilayer membrane (lcHBLM)-modified electrodes, GCE surfaces were modified with 4-dodecylbenzenediazonium (DDAN) followed by the modification with dihexadecyl phosphate (DHP) as the second layer. For the preparation of short-chain hybrid bilayer membrane (scHBLM)-modified electrodes, GCE surfaces were modified with 4-ethyldiazonium (EDAN) as the first layer and bis(2-ethylhexyl) phosphate (BEHP) was utilized as the second layer. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to characterize the bilayer formation. Both positively charged [Ru(NH3)6]3+ and negatively charged ([Fe(CN)6]3-/4-) redox probes were used for electrochemical characterization of the modified surfaces using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). EIS results showed a decrease in charge transfer resistance (Rct) upon incubation of Aβ1–42 on the hybrid bilayer-modified surfaces. This framework provides a promising electrochemical platform for designing hybrid bilayers with various physicochemical properties to study the interaction of membrane-bound receptors and biomolecules on surfaces.

Recent State and Challenges in Spectroelectrochemistry with Its Applications in Microfluidics

“…It is well-known that UV-Vis SEC has been applied in many fields, for example, in electron transfer processes [ 55 ], solar cells [ 31 , 56 ], memory devices [ 57 ], and the determination of compounds of biological interest [ 10 , 58 , 59 , 60 ]. A detailed summary of the chosen examples’ electrode configurations and light arrangements is given in Table 2 .…”

“…The combination of SERS with electrochemistry has emerged as a powerful tool to monitor the structural changes of surface adsorbates [ 95 , 96 ], reaction intermediates [ 97 , 98 ], and quantitative analysis of electrolysis products [ 24 , 60 ]. Daniel and co-workers showed that the SERS SEC technique achieved a theoretical ferricyanide detection limit (~1.5 × 10 −8 M) in a 0.1 M KCl solution [ 24 ].…”

“…The NPs on the slide are thus brilliantly illuminated against the dark background. Then the LSPR is tracked by scattering in the near-infrared region [ 60 , 156 , 157 , 158 , 159 ]. The LSPR extinction maximum of the NP can be measured with DFM and recorded using an electron multiplying charge-coupled device (EMCCD) camera.…”