Label‐free detection techniques for protein microarrays: Prospects, merits and challenges

Abstract

Protein microarrays, on which thousands of discrete proteins are printed, provide a valuable platform for functional analysis of the proteome. They have been widely used for biomarker discovery and to study protein-protein interactions. The accomplishments of DNA microarray technology, which had enabled massive parallel studies of gene expression, sparked great interest for the development of protein microarrays to achieve similar success at the protein level. Protein microarray detection techniques are often classified as being label-based and label-free. Most of the microarray applications have employed labelled detection such as fluorescent, chemiluminescent and radioactive labelling. These labelling strategies have synthetic challenges, multiple label issues and may exhibit interference with the binding site. Therefore, development of sensitive, reliable, high-throughput, label-free detection techniques are now attracting significant attention. Label-free detection techniques monitor biomolecular interactions and simplify the bioassays by eliminating the need for secondary reactants. Moreover, they provide quantitative information for the binding kinetics. In this article, we will review several label-free techniques, which offer promising applications for the protein microarrays, and discuss their prospects, merits and challenges.

Kinetic analysis of the weak affinity interaction between tris and lysozyme

“…2. Due to the weak binding between the two molecules 14 , the real-time curves appear a typical transient reaction trend that the complex formed by the two molecules dissociates after PBS injection. To resolve the kinetic parameter of the interaction between tris and lysozyme, the pseudo-first-order interaction kinetics which relates to the onestep simple reactions is introduced (see Eq.…”

Recent Advances in Nanobiotechnology and High-Throughput Molecular Techniques for Systems Biomedicine

“…Chemo-absorptive coatings and all electronic ultrasensitive detection provide a direct interface to volatile compounds from the disease-correlated odor source such as skin, sputum, urine, and breath (Oh et al, 2011). Other major approaches for label-free detection for quantitative bioassays are based on principles of electrochemistry (Sadik et al, 2009) or surface plasmon resonance (Ray et al, 2010). For a multiplexed detection, thousands of discrete DNAs, proteins or other biomolecules can be spotted and immobilized on solid surfaces in a microarray format.…”

Label free detection of specific protein binding using a microwave sensor

“…2,3 In addition, the use of labels can require chemically modification of the sample that may subsequently interfere with the binding site of the analyte of interest. 1 Surface plasmon resonance (SPR) is a label free optical method that uses the reflectivity of a thin metal layer (typically gold) to measure changes in the refractive index. Changes in the SPR signal occur when species bind to the surface or to an immobilized target.…”

“…The reflected signal depends on the material under test and changes in this signal arising from 2 | J. Name., 2012, 00, [1][2][3] This journal is © The Royal Society of Chemistry 2012 changes in the permittivity can be linked to the composition of the material. The permittivity is a measure of how an electric field is affected by a dielectric medium and accounts for both the stored energy (ε') as well as the loss of energy (ε'') within the material.…”