Microfluidic immunoaffinity separations for bioanalysis

Peoples, Michael C.; Karnes, H. Thomas

doi:10.1016/j.jchromb.2007.08.030

Cited by 47 publications

(36 citation statements)

References 86 publications

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“…However, fluorescent labels are usually preferred due to the high sensitivity, the -compared to radioisotope labeling, which could be also very sensitive -simple sample handling, as well as the availability of easy and fast labeling procedures. Fluorescent labels can be detected using standard fluorescence readers (Peoples and Karnes, 2008;Bally et al, 2006). Despite of all the advantages offered by the label based detection, it still faces some drawbacks.…”

Section: Substratementioning

confidence: 99%

The Impact of Diffusion on Biochemical Assay Kinetics in 3d-Hydrogel Microarrays

Mahmoud¹

2015

JOSHA

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JOSHA is a service that helps scholars, researchers, and students descover, use, and build upon a wide range of content DeclarationI hereby confirm that this master thesis at hand is solely my own written work and that no other sources, than those indicated in the references, were used.All text passages and diagrams, quoted or paraphrased, from these sources have been properly acknowledged as such and fully cited.This thesis has not been submitted in the same, similar or even partial version to another examination board and was not published elsewhere. In the past few years, this technology has developed a lot with the implementation of novel surface chemistries, detection techniques, and different assay formats. 3D-hydrogel microarrays were developed using unique immobilization techniques based on hydrophilic polymer networks. The 3D polymer network attaches and immobilizes the capture molecules onto the surface in form of a spot with molecules immobilized both on the surface and inside the gel matrix. This retains the molecule's natural confirmation and structure and enables higher immobilization efficiency, which allows for higher sensitivity. However, the achieved sensitivities are still far from the theoretical limit and in many cases, long incubation times are required. These limitations are caused by both the resolution of the used detection techniques and the assay kinetics. This hinders the transfer of the technology from the laboratory to routine diagnostics.The kinetics of a biochemical assay in a microarray can be controlled either by the transport of molecules to the spot or by the binding interaction itself. This work focuses on studying the assay kinetics in 3D-hydrogel microarrays in order to understand and characterize the limiting step for signal development. To simulate conditions of high affinity binding partners and therefore reduce the influence of the reaction kinetics, the biotin-streptavidin system was selected as the biological model for this work.A microarray to study the kinetic processes involved in the signal development was designed and the optimum working concentrations for kinetic characterization were defined. To confirm the mass transport limited kinetics, the measured kinetics was compared to the ideal reaction kinetics depending on the affinity parameters for biotin-streptavidin interaction. The ideal reaction kinetics was three orders of magnitude faster than measured kinetics. The two-compartment model, which is widely used to describe the assay kinetics in 2D microarrays, was used to fit the observed kinetics. However, a deviation from the model after the initial phase of signal development was observed. A hypothesis was made that this deviation is due to an additional diffusion step in the hydrogel. Therefore, a microarray model to study this diffusion step was designed. In this model, the microarrays were dip coated with hydrogel layers of various thickness and mesh sizes. This model simulated conditions where the signal development should depend only on the diffusion t...

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Section: Substratementioning

confidence: 99%

The Impact of Diffusion on Biochemical Assay Kinetics in 3d-Hydrogel Microarrays

Mahmoud¹

2015

JOSHA

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“…Accordingly, there is an urgent need in the clinical laboratory for smaller, faster, and cheaper devices in order to make analytical results available with high accuracy at the patient's bedside (point-of-care diagnostics) [90,91]. The development of devices based on miniaturized microfluidic technologies (e.g., LC or CE in conventional format or in microchip format) coupled to immunological platforms is one of the most promising ways to solve some of the problems concerning the increasing need to develop highly sensitive, fast, and economic methods of analysis in medical diagnostics (Table 1) [92][93][94]. A number of factors that shape the invention and introduction of these devices are explored in this review.…”

Section: Iace For the Quantification Of Predictive Biomarkersmentioning

confidence: 99%

Immunoaffinity capillary electrophoresis: A new versatile tool for determining protein biomarkers in inflammatory processes

Guzman¹,

Phillips

2011

Electrophoresis

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Many diseases caused by inflammatory processes can progress to a chronic state causing deterioration in the quality of life and a poor prognosis for long-term survival. To address inflammatory diseases effectively, early detection and novel therapeutics are required. However, this can be challenging, in part because of the lack of early predictive biomarkers and the limited availability of adequate technologies capable of the identification/characterization of key predictive biomarkers present in biological materials, especially those found at picomolar concentrations and below. This review highlights the need for state-of-the art methodologies, with high-sensitivity and high-throughput capabilities, for determination of multiple biomarkers. Although many new biomarkers have been discovered recently, existing technology has failed to successfully bring this advancement to the patient's bedside. We present an overview of the various advances available today to extend the discovery of predictive biomarkers of inflammatory diseases; in particular, we review the technology of immunoaffinity capillary electrophoresis (IACE), which combines the use of antibodies as highly selective capture agents with the high resolving power of capillary electrophoresis. This two-dimensional hybrid technology permits the quantification and characterization of several protein biomarkers simultaneously, including subtle structural changes such as variants, isoforms, peptide fragments, and post-translational modifications. Furthermore, the results are rapid, sensitive, can be performed at a relatively low cost, without the introduction of false positive or false negative data. The IACE instrumentation can have relevance to medical, pharmaceutical, environmental, military, cultural heritage (authenticity of art work), forensic science, industrial and research fields, and in particular as a point-of-care biomarker analyzer in translational medicine.

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“…Microchip electrophoresis has been proven to be a powerful tool for the separation of various chemical species from small molecules to macromolecules such as DNA and protein [26,27]. Microchip electrophoresis combined with immunoassay can separate rapidly the free antigen and antibody from the bound antigen and antibody.…”

Section: Introductionmentioning

confidence: 99%

Competitive immunoassay of phenobarbital by microchip electrophoresis with laser induced fluorescence detection

Huang

Zhao

Shi

et al. 2011

Analytica Chimica Acta

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Microfluidic immunoaffinity separations for bioanalysis

Cited by 47 publications

References 86 publications

The Impact of Diffusion on Biochemical Assay Kinetics in 3d-Hydrogel Microarrays

The Impact of Diffusion on Biochemical Assay Kinetics in 3d-Hydrogel Microarrays

Immunoaffinity capillary electrophoresis: A new versatile tool for determining protein biomarkers in inflammatory processes

Competitive immunoassay of phenobarbital by microchip electrophoresis with laser induced fluorescence detection

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