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

Herein, a novel hybrid bilayer membrane is introduced as a platform to study the aggregation of amyloid-beta(1-42) (A beta(1-42)) 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 (1cHBLM)-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 (R-ct) upon incubation of A beta(1-42) 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.

Automated summary

A novel hybrid bilayer membrane is introduced as a platform for studying the aggregation of amyloid-beta peptide on surfaces. The modified electrodes were characterized using XPS and ToF-SIMS, and electrochemical methods were used to investigate the interaction of the modified surfaces with the amyloid-beta peptide. The results showed a decrease in charge transfer resistance upon incubation of the peptide, indicating the potential of this platform for studying membrane-bound receptors.