New bioanalytical platform based on the use of avidin for the successful exfoliation of multi-walled carbon nanotubes and the robust anchoring of biomolecules. Application for hydrogen peroxide biosensing

GUTIERREZ, F.A.; RUBIANES, M.D.; RIVAS, G.A.

ANALYTICA CHIMICA ACTA

ELSEVIER SCIENCE BV

Año: 2019 vol. 1065 p. 12 - 12

0003-2670

e are reporting an innovative building-block for the development of biosensors based on the non-covalent functionalization of multi-walled carbon nanotubes (MWCNTs) with avidin (MWCNTs-avidin). In this work, at variance with previous reports, avidin has the double role of simultaneously being the exfoliating agent of MWCNTs and the platform for anchoring different biotinylated biomolecules. The optimum dispersion was obtained by sonicating for 5.0 min 0.50 mgmL −1 MWCNTs with 1.00 mgmL −1 avidin solution prepared in 50:50 v/v ethanol/water. As proof-of-concept, we immobilized biotinylated horseradish peroxidase (b-HRP) at glassy carbon electrodes (GCE) modified with MWCNTs-avidin to develop a hydrogen peroxide biosensor using hydroquinone as redox mediator. Surface plasmon resonance, electrochemical impedance spectroscopy, cyclic voltammetry and amperometry demonstrated that, even after the partial denaturation of avidin due to the drastic conditions used to functionalize