Detection of disease biomarkers using a novel multi-analyte immunoassay
Date
2007
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Abstract
Biomarkers provide clinicians with an important tool for disease assessment. Many different biomarkers have been discovered making it readily apparent that no single biomarker can be relied upon for accurate disease detection which has led towards the push for new multi-analyte screening methods. There are, however, currently few inexpensive multi-analyte methods that can use these biomarkers for disease detection in a point-of-care setting. This dissertation details the development of a novel immunoassay which bridges the gap between traditional immunoassays and high density microarrays by utilizing microfluidics, immunoassays and micellar electrokinetic chromatography (MEKC). This chemistry, the Cleavable Tag Immunoassay (CTI), is a low- to medium-density heterogeneous immunoassay designed to detect up to 20 analytes simultaneously. The multi-analyte CTI is shown to be a useful tool for the detection and quantification of cardiac biomarkers in serum samples. Limit of detection and linear range are reported for all of the biomarkers with LODs on the order of low ng/mL to low pg/mL. The linear range for each of the biomarkers spans the boundary between normal and elevated levels. In addition, the use of a combination of two surfactants in the run buffer which form mixed micelles is shown to improve resolution of CTI tags. Preliminary studies of cleavage kinetics using single particles for an integrated CTI analyzer are also presented including demonstration of the ability to trap and release magnetic particles in a microchip device. Two methods for improving separation efficiency of poly(dimethylsiloxane) including the use of polyelectrolyte multilayers and a simple and effective way to generate a stable hydrophilic glass-like surface for use with microchip CE-EC and CE-fluorescence are also presented. The outcome of this dissertation demonstrates the marriage of immunoassays and microchip MEKC in the CTI shows promise as a new medium-density chemistry for rapid biomarker detection. This work is the first step towards the development of an integrated assay for rapid point-of-care analysis of AMI.
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Subject
biomarkers
cleavable tags
immunoassays
analytical chemistry