The Role of Surface Chemistry in the Efficacy of Protein and DNA Microarrays for Label-Free Detection: An Overview.

Elisa Chiodi,Matthew T Geib,M Selim Ünlü,Allison M Marn

doi:10.3390/polym13071026

Abstract

The importance of microarrays in diagnostics and medicine has drastically increased in the last few years. Nevertheless, the efficiency of a microarray-based assay intrinsically depends on the density and functionality of the biorecognition elements immobilized onto each sensor spot. Recently, researchers have put effort into developing new functionalization strategies and technologies which provide efficient immobilization and stability of any sort of molecule. Here, we present an overview of the most widely used methods of surface functionalization of microarray substrates, as well as the most recent advances in the field, and compare their performance in terms of optimal immobilization of the bioreceptor molecules. We focus on label-free microarrays and, in particular, we aim to describe the impact of surface chemistry on two types of microarray-based sensors: microarrays for single particle imaging and for label-free measurements of binding kinetics. Both protein and DNA microarrays are taken into consideration, and the effect of different polymeric coatings on the molecules’ functionalities is critically analyzed.

Highlights

Microarrays are ordered collections of molecules deposited on a surface in small spots [1,2]
Label-free techniques provide direct assessment of the biomass that is accumulated on the surface, allowing for precise quantification up to the number of captured molecules [15,16], which would be impossible with a labeled technique such as fluorescence, where the need for a secondary fluorescent molecule prevents the possibility of obtaining a direct correlation of the fluorescence signal with the amount of accumulated biomass
We have already mentioned that surface chemistries that produce a tridimentional structure are generally preferred, since they have higher loading capacity and they preserve the molecular structure of the molecules, maintaining unaltered molecular activity

Summary

Introduction

Microarrays are ordered collections of molecules deposited on a surface in small spots [1,2]. Due to the rising popularity of the field of genomics, DNA microarrays were the first to be developed, addressing the need to keep track of many DNA sequences [4]. To this day, DNA microarrays are a well-established method to detect DNA mutations and are widely used in cancer research and diagnosis [5,6,7]. Protein microarrays have gained popularity as an irreplaceable tool for the fields of diagnostics and drug development, as they constitute an efficient method for multiplexed detection of biomarkers and antibodies [8,9,10,11,12]. Label-free techniques provide direct assessment of the biomass that is accumulated on the surface, allowing for precise quantification up to the number of captured molecules [15,16], which would be impossible with a labeled technique such as fluorescence, where the need for a secondary fluorescent molecule prevents the possibility of obtaining a direct correlation of the fluorescence signal with the amount of accumulated biomass

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Conclusion