An Overview of Label-free Electrochemical Protein Sensors.

Mun 'Delanji Vestergaard,Eiichi Tamiya,Kagan Kerman

doi:10.3390/s7123442

Abstract

Electrochemical-based protein sensors offer sensitivity, selectivity and reliabilityat a low cost, making them very attractive tools for protein detection. Although the sensorsuse a broad range of different chemistries, they all depend on the solid electrode surface,interactions with the target protein and the molecular recognition layer. Traditionally, redoxenzymes have provided the molecular recognition elements from which target proteins haveinteracted with. This necessitates that the redox-active enzymes couple with electrodesurfaces and usually requires the participation of added diffusional components, or assemblyof the enzymes in functional chemical matrices. These complications, among many others,have seen a trend towards non-enzymatic-based electrochemical protein sensors. Severalelectrochemical detection approaches have been exploited. Basically, these have fallen intotwo categories: labeled and label-free detection systems. The former rely on a redox-activesignal from a reporter molecule or a label, which changes upon the interaction of the targetprotein. In this review, we discuss the label-free electrochemical detection of proteins,paying particular emphasis to those that exploit intrinsic redox-active amino acids.

Highlights

Genetic information, imprinted on nucleic acids, has always enchanted the researchers and intrigued them into unraveling its secrets
We focus on the label-free electrochemical detection of proteins with particular emphasis to those that exploit intrinsic redox-active amino acids
We studied label-free electrochemical detection of phosphorylation based on the electrooxidation of Tyr in connection with differential pulse voltammetry (DPV) using a screen-printed carbon electrode (SPCE)

Summary

Introduction

Genetic information, imprinted on nucleic acids, has always enchanted the researchers and intrigued them into unraveling its secrets. Molecular expression of this genetic information, are at the very core of biological function. They are the centre of most pathological conditions and most disease biomarkers are proteins. There are basically four different pathways for electrochemical detection of proteins: a change in the electrochemical signal of (i) a label, which selectively binds with the target protein, (ii) electro-active amino acids of antibody or target protein, (iii) a secondary antibody-tagged probe, (iv) aptamers- and (v) an enzyme-tagged probe can be monitored [4,6,7]. We focus on the label-free electrochemical detection of proteins with particular emphasis to those that exploit intrinsic redox-active amino acids. We present recent work carried out by our group as well as work by other groups

Intrinsic redox-active amino acids-based sensors: direct application

Antibody-based protein detection

Aptamer-based protein detection

Nanotechnology and label-free protein sensors

Findings

Challenges for development of point-of-care biosensors