Development of an electrochemical metal-ion biosensor using self-assembled peptide nanofibrils

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.