title: Sensitive Detection of Cardiac Biomarkers Using a Magnetic Microbead Immunoassay.
abstract: To achieve improved sensitivity in cardiac biomarker detection, a batch incubation magnetic microbead immunoassay was developed and tested on three separate human protein targets: myoglobin, heart-type fatty acid binding protein, and cardiac troponin I. A sandwich immunoassay was performed in a simple micro-centrifuge tube allowing full dispersal of the solid capture surface during incubations. Following magnetic bead capture and wash steps, samples were analyzed in the presence of a manipulated magnetic field utilizing a modified microscope slide and fluorescent inverted microscope to collect video data files. Analysis of the video data allowed for the quantitation of myoglobin, heart-type fatty acid binding protein and cardiac troponin I to levels of 360 aM, 67 fM, and 42 fM, respectively. Compared to the previous detection limit of 50 pM for myoglobin, this offers a five-fold improvement in sensitivity. This improvement in sensitivity and incorporation of additional markers, along with the small sample volumes required, suggest the potential of this platform for incorporation as a detection method in a total sample analysis device enabling multiplexed detection for the analysis of clinical samples.
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, USA.
authors.forename: Christine F
authors.initials: CF
authors.lastname: Woolley
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Hayes
keywords: Cardiac biomarker; assay optimization; micro-immunoassay; microbead immunoassay; quantitation limit; sandwich immunoassay