Giant magnetoresistive biosensor for myoglobin immunoassay

Abstract

Sensitive and quantitative immunoassay of cardiac markers is vital for heart disease diagnosis, and myoglobin, serves as the earliest indicator of acute myocardial infarction (AMI). However, traditional methods and commercial tools for myoglobin immunoassay, which are usually based on optical techniques, have inherent drawbacks that signals could be easily interfered by background noises and the required expensive equipments are difficult to be integrated and portable. Giant magnetoresistive (GMR) biosensors, with the high sensitivity and economy, have been a promising alternative in this regard. In this study, we advance myoglobin immunoassay by integrating GMR biosensor detection system and magnetic particles with a classic sandwich strategy. A corresponding AC detection platform employing time division multiplexing and bandpass filtering techniques is developed for testing. The myoglobin of interest is sandwiched between immobilized antibody and biotinylated antibody labeled with magnetic particles. Two group assays of various concentrations with different biotinylated antibodies were performed. And a detection limit of 1 ng/mL and assay time less than 30 min were achieved. This is the first demonstration of such myoglobin assay using GMR biosensors. With its high sensitivity and simplicity of detection scheme, the GMR biosensor detection system is an excellent candidate suitable and promising for biomarker diagnosis and biomedical applications.