Development of an Electrochemical Metal-Ion Biosensor Using Self-Assembled Peptide Nanofibrils

Abstract

This article describes the combination of self-assembled peptide nanofibrils with metal electrodes for the development of an electrochemical metal-ion biosensor. The biological nanofibrils were immobilized on gold electrodes and used as biorecognition elements for the complexation with copper ions. These nanofibrils were obtained under aqueous conditions, at room temperature and outside the clean room. The functionalized gold electrode was evaluated by cyclic voltammetry, impedance spectroscopy, energy dispersive X-ray and atomic force microscopy. The obtained results displayed a layer of nanofibrils able to complex with copper ions in solution. The response of the obtained biosensor was linear up to 50 μM copper and presented a sensitivity of 0.68 μA cm⁻² μM⁻¹. Moreover, the fabricated sensor could be regenerated to a copper-free state allowing its reutilization.

A review on detection of heavy metal ions in water – An electrochemical approach

“…These self-assembled peptides are catching the eyesight of researchers due to its flexibility, stability, large surface-to-volume ratio, short diffusion length and chemical diversity. So, Viguier et al, have proposed the system with ion selective electrodes in which gold electrode was modified with cysteine containing self-assembled nanofibrils to detect the Cu 2+ ions [187]. In this study, a strong interaction was observed between the nanofibrils containing a cysteine group and this is the result of strong anchorage between sulfur atoms of cysteine and gold surface of working electrode.…”

Fabrication of Nanostructures Using Self-Assembled Peptides as Templates: The Diphenylalanine Case

“…This casting of metallic nanowires starts with the preparation of an FF stock solution in HFP at a concentration of 100 mg/mL as explained in Section 2.2.1. The peptide stock solution is then diluted with water [14,15] Magnetic alignment Noncontact method, sample needs to be magnetic or to be modified with magnetic NPs [16,17] Inkjet printing Noncontact method, sample in solution [18] Spin casting Noncontact method, sample in liquid [19] Atomic force microscopy (AFM) Contact method [20,21] Thiol-based immobilization Sample needs to be functionalized with thiol groups [22] to a final concentration of 2 mg/mL. The formation of a white precipitate can be immediately observed with the naked eye, indicating the self-assembly of FF NTs.…”

Short peptides as biosensor transducers

“…This result also explains the ion selectivity of the peptide, since the Gly-His-Gly isomer is likely unable to form the tetradentate complex for steric reasons, and monodentate complexation by histidine is not selective. A higher level of design is embodied in an octapeptide that forms aggregate nanofibrils covering the surface of the electrode, and changes its conformation upon binding of copper, thus modifying the electrode activity [10]. Ion-sensitive peptides have been designed also taking inspiration from more complex naturally occurring motifs: the zinc-finger peptide sequence has been used to build up a zinc Förster resonance energy transfer (FRET) fluorimetric sensor [11].…”