Mass Transfer in Amperometric Biosensors Based on Nanocomposite Thin Films of Redox Polymers and Oxidoreductases

Michael V Pishko,Aleksandr L Simonian,Alexander Revzin

doi:10.3390/s20300079

Michael V Pishko, Aleksandr L Simonian + Show 1 more

Open Access

https://doi.org/10.3390/s20300079

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Abstract

Abstract : Mass transfer in nanocomposite hydrogel thin films consisting of alternating layers of an organometallic redox polymer (RP) and oxidoreductase enzymes was investigated. Multilayer nanostructures were fabricated on gold surfaces by the deposition of an anionic self-assembled monolayer of 11-mercaptoundecanoic acid, followed by the electrostatic binding of a cationic redox polymer, poly[vinylpyridine Os( bis -bipyridine) 2 Cl-co-allylamine], and an anionic oxidoreductase. Surface plasmon resonance spectroscopy, Fourier transform infrared external reflection spectroscopy (FTIR-ERS), ellipsometry and electrochemistry were employed to characterize the assembly of these nanocomposite films. Simultaneous SPR/electrochemistry enabled real time observation of the assembly of sensing components, changes in film structure with electrode potential, and the immediate, in situ electrochemical verification of substrate-dependent current upon the addition of enzyme to the multilayer structure. SPR and FTIR-ERS studies also showed no desorption of polymer or enzyme from the nanocomposite structure when stored in aqueous environment occurred over the period of three weeks, suggesting that decreasing in substrate sensitivity were due to loss of enzymatic activity rather than loss of film compounds from the nanostructure.

Highlights

The electrostatic layer-by-layer assembly of nanocomposite films composed of alternating layers of oppositely charged molecules has been a subject of numerous publications.[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16] A promising application of this assembly approach is in the area of biosensor fabrication
Calvo and co-workers used QCM, AFM, and electrochemical analysis to investigate the assembly process,[4, 6] while others employed XPS and SPR for the same purpose.[6, 13]. In this manuscript we described mass transfer and hydrogel swelling in electrostatically assembled nanocomposite thin films containing redox polymers and oxidoreductases
While emphasis in this study was placed on the characterization of nanocomposite thin films containing GOX, we have studied nanocomposite structures containing POD and LOX

Summary

Introduction

The electrostatic layer-by-layer assembly of nanocomposite films composed of alternating layers of oppositely charged molecules has been a subject of numerous publications.[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16] A promising application of this assembly approach is in the area of biosensor fabrication. First proposed and implemented by Heller and co-workers,[17] this method entails the electrostatic binding between cationic redox polymers and anionic oxidoreductase enzymes which results in the transfer of electrons from the enzyme via the redox polymer to the electrode surface.[4, 6, 8, 13, 14] layer-by-layer assembly of oppositely charged redox polymers and oxidoreductase enzymes takes advantage of this method. Calvo and co-workers used QCM, AFM, and electrochemical analysis to investigate the assembly process,[4, 6] while others employed XPS and SPR for the same purpose.[6, 13]

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